8. BRACHYPTEROUS SPHAEROCERIDAE

by O. W. RICHARDS

(Imperial College of Science and Technology)

THE Sphaeroceridae show a special development of wingless genera and species

on Mt. Elgon and to a less extent on other mountains in the same region.

An account of a number of them has already been published (Richards, 1938).

The Ruwenzori Expedition brought back three new forms together with

additional specimens of some of those already described from Mt. Elgon. It

is proposed, after dealing with this material, to give some notes on the other

wingless or short-winged members of the family, and to consider the evolutionary

and taxonomic problems which their identification raises. A key to all the

brachypterous Sphaeroceridae is included.

Mesaptilotus gen. n.

Wings and halteres absent. Eyes large, emarginate above and _ below.

Anterior ocellus absent, posterior ones quite rudimentary or in one specimen

absent. Five small interfrontal bristles, one ocellar, two superior orbitals, one

external vertical (inner vertical and postvertical so small as to be confused with

miicrochaetes) on each side. Mesonotum hardly narrower than head with eyes,

one small humeral, one moderate notopleural, one small prealar, one small and

one large postalar, one moderate posterior dorsocentral on each side. Scutellum

about twice as wide as long with four widely spaced bristles; one strong sterno-

pleural bristle. Mid-tibia with a pair of dorsal bristles at one-third, an antero-

dorsal at two-thirds, a pair of dorsals at four-fifths and an apico-ventral spur.

Abdomen egg-shaped, posteriorly rounded, nearly twice as long as broad, margin

sharp, deflexed; sternites very broad, moderately sunk into tergites; first tergal

plate (—I-+I1) considerably constricted anteriorly but the constriction overhung

by enlarged posterior part of same plate, so that neck-like portion is incon-

spicuous, no part of abdominal margin with raised border ; abdominal bristles all

short. Type of genus Mesaptilotus pollinosus sp. n.

Mesaptilotus pollinosus sp. n.

Female (Fig. 1). Black, densely brownish-grey pollinose, dull, hind tarsi a

little paler. Ocellar bristles on a dusted area which sends forwards a very narrow

triangular projection, extending half-way across frons. The interfrontal and

II, 8 (a)

$30 RUWENZORI EXPEDITION

orbital bristles are on similarly dusted, narrow stripes, but the outer stripe is

narrowly separated from the eye by a more shining area. Central region between

the stripes dark velvety.

Length 2:5 mm.

Head with mouth-cavity large, mouth parts normal, palpi normal, with

short, black bristles; vibrissa about two-thirds as long as width of vertex, set well

above oral margin which bears an irregular double row of fine hairs of which

one close to and parallel with vibrissa, and another a little farther back, and

directed upwards are a little stronger but not one-quarter length of vibrissa;

jowls dull, with very fine striation, at vibrissal angle about as high as length of

third antennal segment, about twice as high posteriorly, oral margin not raised,

occipital margin feebly defined, the two margins together forming a rounded

right-angle; eyes quite large, longitudinal diameter nearly twice vertical one,

which is little shorter than greatest height of jowls, margin ventrally broadly but

shallowly emarginate, dorsally (opposite antenna) rather deeply emarginate;

ocelli very small, anterior one absent, posterior pair at level of back of eyes; face

dull, vertical, shallowly excavated, mouth-edge little prominent, facial “‘knob”’

rather prominent though obtuse; antennae divergent, widely separated, third

segment suboval, arista three times as long as antenna, with short pubescence ;

vertex dull, velvety black, with orbits, interfrontal stripes and triangle based

on ocelli browner, central triangle extending to frontal suture anteriorly, twice

as long as broad posteriorly ; head on each side with the following bristles: five

weak interfrontals, one oceilar, two superior orbitals (anterior outwardly,

posterior inwardly directed), normal most anterior superior orbital reduced to a

minute microchaete, resembling an inferior orbital (though these appear to be

absent), one external vertical, two minute bristles perhaps representing external

occipital and postvertical.

Mesonotum in dorsal view about half as broad again as long, hardly narrower

and little longer than head with eyes, surface dull, finely pollinose with numerous

fine microchaetes (about 24 rows between prealars), a little convex, humeral calli

very weak, suture and postalar calli obsolete, depression in front of scutellum

distinct but linear, bristles on each side are one short stout humeral, one moderate

notopleural, one small prealar, one large and one small postalar, one moderate

dorsocentral just in front of scutellum; scutellum somewhat reduced but

posterior margin rounded, about twice as wide as long, lateral and median

bristles widely-spaced, each as long as scutellum or rather longer ; mesopleuron

dull, meropleurite, metapleuron and mediotergite very reduced, one moderate

sternopleural bristle.

Legs with fore femur not thickened, with short black bristles of which three

distal, postero-ventral ones are a little longer, tibia with short bristles only,

tarsus not quite as long as tibia, basitarsus as long as next two segments

together; mid-trochanter with no bristle, femur not thickened, with one stout,

BRACHYPTEROUS SPHAEROCERIDAE 831

distal antero-dorsal bristle, tibia with a pair of dorsal bristles at one-third and at

four-fifths and an antero-dorsal at two-thirds, and a short apico-ventral, tarsus

as long as tibia, basitarsus as long as next two segments together, with no long

bristles; hind femur not thickened, with no long bristles, tibia with no bristles

or spurs, basitarsus conspicuously thickened, not quite two-thirds as long as

segment 2.

Abdomen rather large, egg-shaped, twice as long as broad, dorsal surface

convex, not much constricted anteriorly except immediately before attachment

to thorax, widest at middle of second tergal plate (—III), first tergal plate

(=I-+I]) posteriorly one and a half times as wide as thorax, median length

equal to that of mesonotum, tergite III very little wider and shorter than I-+-II,

IV of about same size as III, V a little narrower and shorter, VI and VII just

visible beyond V as very short, narrow plates; tergites all with sharp-edged but

not raised lateral margins, posterior margins of II-V narrowly thinner and more

hyaline; sternites very broad, moderately sunk into tergites, dull, with rather

sparse, short bristles, I[+-II reduced, III large, IV and V a little, VI and VII

much smaller; cerci apparently reduced and retracted; tergites dull pollinose,

each with about six transverse rows of short bristles, none longer even at

margins, about 30 bristles in row on III.

Male. Differs only as follows:—Front of vertex a little and hind tarsi more

distinctly ferruginous. Forward extension of dusted ocellar area much shorter.

Length 2:25 mm. Vestige of anterior ocellus present; fore- and mid-femur a

little more thickened; abdomen similar in general shape, but tergite VI asym-

metrical (reduced on right side), VII not visible externally, genitalia large and

convex, forceps not visible; sternites with denser and more outstanding, biack

pubescence, V with its margin reflexed but rounded.

UcaAnbDA: Ruwenzori Range, Namwamba Valley, 13,500 ft., xi1.34., 1.35

(E. G. Gibbins), 9 holotype. Same place and date, 11-12,000 ft., sweeping low

herbage (F. W. Edwards), 9 allotype. Ruwenzori, above Lake Bujuka, 12,750 ft.,

2.11.49, on carrion (G. Salt), 9 paratype. The type specimens are in the British

Museum (N.H.). The ocelli seem to be variable in this species. Traces of all

three are present in the male; Salt’s female has none, whereas Edwards’ specimen

has distinct traces of the lateral ones. Salt’s specimen also has the eyes flattened

rather than emarginate below.

Binorbitalia gen. n.

Wings and halteres absent. Eyes large, ocelli, especially the anterior one,

small, whole dorsal surface, including that of head, extremely shining ; four small

interfrontals, one ocellar, two strong superior orbitals, one strong external

vertical, a minute external occipital and postvertical on each side. Mesonotum

just narrower than head with eyes, one strong humeral, one strong notopleural,

832 RUWENZORI EXPEDITION

one moderate prealar, one strong and one weak postalar, one weak prealar, two

dorsocentrals (one presutural and rather more lateral) on each side. Scutellum

oval, anterior margin being curved (convex anteriorly) and posterior margin not

quite semicircular, with four long, widely spaced bristles ; one long sternopleural.

Mid-tibia with a pair of dorsal bristles just above one-third, a pair of dorsal

bristles (with a strong central one a little below them and a weaker central one a

little above them) just below two-thirds, and an apico-ventral bristle. Hind tibia

without bristles, with a minute, apico-ventral spur less than half as long as

diameter of tibia; hind basitarsus unusually narrow for a member of this family,

not quite as long as next segment. Abdomen elongate, nearly twice as long as

broad, margin sharp, deflexed; sternites very broad, moderately sunk into

tergites; first tergal plate (=I+II) a little and only gradually contracted

anteriorly, no very distinct necklike portion, tergites I-III with slight raised

lateral margins; abdomen with long macrochaetes, nearly as long as the

intermediate plates to which they are at right angles.

Type of genus Binorbitalia mtidissima sp. n,

Binorbitalia nitidissima sp. n.

Female (Fig. 2). Black, very shining, without faintest trace of tomentum

except on ventral half of mesopleuron; anterior third of vertex, antennae, face,

jowls, legs and ventral half of mesopleuron reddish-brown, fore tibiae and tarsi

a little darker.

Length 3:1 mm.

Head with mouth-cavity large, mouth parts normal, palpi brown, hardly

clavate, with long terminal bristle ; vibrissa two-thirds as long as width of vertex,

set almost on oral margin which bears a few irregular rows of forwardly-directed

bristles, none one-quarter as long as vibrissa; jowls shining, very finely shag-

reened, at vibrissal angle a little narrower than width of third antennal segment,

three times as wide posteriorly, oral margin not raised, occipital margin not

defined, the two margins meeting in a rounded right-angle; eye large, longi-

tudinal diameter one and a half times vertical one which is little greater than

greatest height of jowls, margin ventrally broadly but shallowly, dorsally only

feebly emarginate; ocelli small but distinct, posterior pair distinctly in front of

posterior eye-margin ; face shining, vertical, moderately excavated, mouth-edge

a little upcurved, facial “‘knob”’ rather prominent; antennae divergent, rather

widely separated, third segment oval, arista four times as long as antenna,

with short pubescence; vertex strongly shining throughout, central triangle not

defined, head on each side with the following bristles, five weak interfrontals,

one ocellar, two superior orbitals (anterior backwardly and outwardly, posterior

inwardly directed; the normal most anterior one not at all developed), one

BRACHYPTEROUS SPHAEROCERIDAE 833

external vertical, one external occipital and postvertical about one-third as long

as other bristles.

Mesonotum in dorsal view as long as broad, a little narrower and nearly twice

as long as head with eyes, surface strongly shining with few (not more than

twenty-five in all) irregularly-placed microchaetes, a little convex, humeral and

postalar calli hardly defined, suture obsolete, depression in front of scutellum

moderately broad but shallow, bristles on each side are one long humeral, one

long notopleural, one short presutural interalar, one prealar, one very long and

Fics. 1-3.—General dorsal views, microchaetes omitted: (1) Mesaptilotus pollinosus Richards,

type 2; (2) Binorbitaha nitidissima Richards, type 2; (3) Aluligera montana Richards,

type 9; (3a) Mesothorax and wings of allotype g, bristles omitted. Scale line equals 1-0 mm,

one short postalar, one long dorsocentral in front of scutellum and a long

presutural one which is nearer sides; scutellum not much reduced, oval, hardly

twice as broad as long, with four long, widely-spaced bristles, lateral pair some-

what longer, rather more than twice as long as scutellum; mesopleuron shining

except for sternopleuron which bears one long bristle ; meropleurite, metapleuron

and mediotergite much reduced.

Legs with fore femur somewhat thickened with two dorsal and, in distal half,

four longer postero-ventral bristles, tibia with one distal postero-dorsal bristle,

II, 8 (a*)

834 RUWENZORI EXPEDITION

tarsus as long as tibia, basitarsus as long as next two segments together; mid-

trochanter with no bristles, femur not thickened with a stout, distal, antero-

dorsal bristle, tibia with a pair of dorsal bristles at one-third, three small dorsal

bristles at same level at three-quarters, and a longer dorsal bristle just distal to

them, apico-ventral not as long as diameter of tibia, basitarsus not quite half as

long as tibia, as long as remaining segments together, with no long bristle; hind

femur hardly thickened with no longer bristles, tibia without bristles or spurs,

basitarsus little thickened for a member of the family, as long as segment 2.

Abdomen long-oval, fully one and a half times as long as head + thorax (in-

cluding scutellum), three times as long as broad, dorsal surface convex, gradually

but not distinctly constricted anteriorly, widest at middle of tergite III, first

tergal plate (—I--II) posteriorly a little wider than thorax, its median length a

little greater than that of mesonotum, tergite III hardly wider than and two-

thirds as long as I+-II, IV a little narrower and shorter than III, V considerably

shorter and narrower, VI still smaller and VII only just visible; all tergites with

margins deflexed, sharp-edged and a little thickened ; sternites broad, moderately

sunk into tergites, shining with about four rows of widely-spaced microchaetes,

I+II reduced, III-V large and of equal size, VI distinctly shorter and VII

rather small; cerci finger-shaped but apparently partly fused, each with two long

bristles; tergites shining, II-V each with four very long, erect, dorsal bristles

in transverse row just before posterior margin, also with three or four irregular,

transverse rows of recumbent microchaetes (about thirty in row on III) which

at sides become two-thirds as long as erect bristles.

Kenya: Aberdare range, Nyeri track, 10,500 ft., x.34 (F. W. Edwards),

9 type.

Resembles Paraptilotus flavipes Richards, 1938, of Mt. Elgon, but the anterior

superior orbital is absent and the apico-ventral bristle of the mid-tibia much

shorter.

Aluligera gen. n.

Female. Wings reduced to minute scales about half size of third antennal

segment. Male wings oval, about as long as width of head between eyes pos-

teriorly, extending beneath and some way beyond scutellum, with indications of

costa and a “‘subcosta”’ to two-fifths. Both sexes. Halteres absent. Eyes large.

Ocelli, especially anterior one, minute. Two or three minute interfrontals, one

ocellar, three superior orbitals (increasing markedly in size posteriorly, the most

anterior one less than half length of next one), a moderate outwardly directed

external vertical, a small inner vertical and a small postvertical (sometimes

missing from one side) on each side. Mesonotum a little narrower than head with

eyes, one small humeral, one moderate notopleural, one small prealar, one long

and one small postalar, two supra alars (one presutural), two long dorso-

centrals (one presutural) on each side. Scutellum semicircular with four very

BRACHYPTEROUS SPHAEROCERIDAE 835

long, widely-spaced bristles; one strong sternopleural bristle. Mid-tibia with a

pair of dorsal bristles just above one-third, a pair of dorsal bristles (sur-

mounted by a small antero-dorsal) just below two-thirds, and an apico-ventral

bristle. Hind tibia without bristles or apico-ventral spur. Abdomen egg-shaped

posteriorly-rounded, nearly twice as long as broad, margins sharp, deflexed;

sternites very broad, moderately sunk into tergites; first tergal plate consider-

ably constricted anteriorly but constriction overhung by enlarged posterior

part of plate, so that neck-like portion is inconspicuous, no part of abdominal

margin with raised border; abdominal microchaetes rather long (none quite

as long as tergal plate from which it arises), recumbent.

Type of genus Aluligera montana sp. n.

Aluligera montana sp. n.

Female (Fig. 3). Orange-brown with mouth parts (except palpi), sterno-

pleuron, metathorax and fore tibiae and tarsi darker; abdomen shining black.

Dorsal surface of head and thorax shining, lateral aspects dull.

Length 1-75 mm.

Head with mouth-cavity moderately large, transverse, mouth parts normal,

palpi normal, yellowish, with one short bristle; vibrissa about three-quarters as

long as width of vertex, set on oral margin which bears an irregular double row

of fine bristles none of which is more than one-sixth as long as vibrissa; jowls

dull, not striate, at vibrissal angle half as high as width of third antennal seg-

ment, four times as high posteriorly, oral margin not raised, occipital margin

not defined, the two margins meeting together in rounded right-angle ; eyes quite

large, longitudinal diameter one and a half times vertical one which is consider-

ably greater than greatest height of jowls, margin ventrally broadly but shal-

lowly emarginate, dorsally with very slight emargination opposite antenna;

ocelli small, posterior pair well in front of level of hind margin of eye; face shin-

ing, vertical, rather strongly excavated, mouth-edge considerably upturned,

facial ““knob’’ hardly developed; antennae divergent, widely separated, third

segment suboval but considerably higher than long, arista five times as long as

antenna, with short pubescence; vertex shining, orbits hardly duller, central

triangle feebly defined, extending to frontal suture anteriorly, twice as long as

broad posteriorly ; head on each side with following bristles, two or three weak

interfrontals, one ocellar, three superior orbitals (the most anterior one not half

as long as central one), one external vertical, one very small external occipital,

one small postvertical.

Mesonotum in dorsal view as long as broad, as broad and nearly twice as

long as head with eyes, surface shining, in all about six widely spaced, longi-

tudinal rows of microchaetes, two acrostical rows more distinct and regular,

notum a little convex, humeral and postalar calli very weak, suture obsolete,

836 RUWENZORI EXPEDITION

depression in front of scutellum distinct but linear, bristles on each side are one

small humeral, one moderate notopleural, one moderate prealar, one large and

one small postalar, one small presutural, one small supraalar, two dorsocentrals

(one just in front of scutellum and one just in front of suture and somewhat more

lateral) ; wings present as a minute, somewhat crumpled scale, not quite as long

as scutellum, twice as long as broad; halteres absent; scutellum rather small,

posterior margin rounded but less than semicircular, about twice as broad as

long, with four long, widely spaced bristles of equal size; whole pleuron dull,

meropleurite, metapleuron and mediotergite very reduced, one strong sterno-

pleural bristle.

Legs with fore femur hardly thickened with one or two longer dorsal and two

or three antero-ventral bristles, tibia with short bristles only, tarsus a little

longer than tibia, basitarsus as long as next two segments together; mid-

trochanter with no longer bristles, femur not thickened, with two antero-dorsal

bristles (the more distal one twice as long as other) and a minute, distal, postero-

dorsal one, tibia with a pair of strong dorsal bristles at one-third, another at

three-quarters, one small postero-dorsal at same level as lower pair, a long

apico-ventral, tarsus a little longer than tibia, basitarsus as long as next two

segments together, with no strong bristles; hind femur not thickened, without

long bristles, tibia without long bristles or spur, basitarsus conspicuously

thickened, hardly more than half as long as segment 2.

Abdomen larger than usual, egg-shaped, somewhat flattened, twice as long as

broad, dorsal surface only moderately convex, not strongly constricted anteriorly

except just at attachment to thorax, widest at end of tergite III, first tergal

plate (=I-+II) posteriorly one-third broader than thorax, its median length

rather more than half that of mesonotum, tergite III very little wider and two-

thirds as long, IV and V each a little shorter and narrower than tergite before,

VI very short and truncate, VII hardly visible; tergites all with sharp-edged

but not raised lateral margins; sternites broad, moderately sunk into tergites, a

little dull, with rather sparse, short bristles, I+-II reduced, I1I-V subequal in

length, VI considerably shorter and VII only a narrow strip; cerci in form of

small, oval plates, each bearing two long, somewhat woolly bristles; tergites

shining but with distinct, scale-like shagreening, each tergite with transverse

row of about fourteen moderately long (about as long as notopleural), recumbent

bristles just before posterior margin, and another transverse row of about eighteen

much smaller ones more anteriorly; spermathecae three, spherical opaque

black, ducts brown, moderately sclerotised.

Male resembles the female except in the following particulars: fore tibiae

and tarsi not darker. Size a little smaller. Depression in front of scutellum

shallower, less marked; wings (Fig. 3a) oval, with distinct membrane, extending

beneath and for half scutellar length beyond scutellum, costa and one other vein

visible proximally, anterior margin distally with two small bristles; abdomen a

BRACHYPTEROUS SPHAEROCERIDAE 837

little narrower, genitalia rather large and swollen, without long bristles, outer

forceps in the form of narrow, curved hooks, anal opening long-oval, sternite

V unmodified, with a transverse row of short, stout, erect bristles just before

posterior margin.

UGANDA: Ruwenzori Range, Namwamba Valley, 8,300 ft., xii.34, 1.35

(Ff. W. Edwards), 2 type; same place, 6,500 ft., same dates, 9 allotype; para-

types, I 9 same data as type, 7 2, 5 ¢ with same data as allotype.

Ocellipsis cyclogaster Richards, 1938.

Kenya: Mt. Elgon, heath zone 10,500-11,500 ft., 9 9, 5 4, ii.35 (F. W.

Edwards). (Fig. 4.)

This species was originally described from a single female collected on Mt.

Elgon by Dr. R. Jeannel. The additional material, besides making it possible

to describe the male, enables me to correct certain statements in the original

description.

Female. Sometimes seven interfrontals, external vertical strong, external

occipital and postvertical sometimes represented by weak bristles; mesonotum

better described as square with angles rounded, bristles (correctly) are one or

two minute humerals, one moderate notopleural, one stout prealar, one small

supra-alar, one long and one small postalar, one moderate prescutellar dorso-

central on each side; mid-tibia ventrally at apex with four small, stout bristles

of equal size; hind tibia dorsally with erect pubescence somewhat longer than

tibial diameter ; abdomen of type female evidently somewhat distorted, correctly

pyriform (in dorsal view), subtruncate behind, first tergal plate (—I-+II)

posteriorly not quite twice as wide as thorax, as long as head + mesonotum;

tergites with a narrow posterior margin which is non-pollinose, moderately

shining ; cerci usually dark.

Male. Resembles female except: abdomen long oval, tergites III-V normal,

rather short, together about as long as I+I1, VI only visible as small triangular

plate on left side, VII larger but broader on left side, genitalia large and project-

ing, without long bristles, anal opening long-oval, pointed dorsally, outer forceps

represented by very small, brownish, triangular plates, inner forceps (probably)

represented by longer, triangular, brownish plates, sternites I-+II as long as

II1+IV-+-V, III and IV short, V longer at sides, but shorter and shallowly

emarginate centrally, all sternites with short, rather sparse, unspecialised

pubescence, somewhat denser along emargination of V.

Ocellipsis lonchomma, Richards, 1938.

Kenya: Mt. Elgon, heath zone 10,500-11,500 ft., 9 11.35 (f°. W. Edwards).

The species was already known in both sexes from this zone of Mt. Elgon,

838 RUWENZORI EXPEDITION

Paraptilotus chaetosoma Richards, 1938 (Fig. 6)

KEnyA: Mt. Elgon, heath zone 10,500-11,500 ft., 9 11.35 (FP. W. Edwards).

Both sexes were described from Mt. Elgon.

Paraptilotus brunneisternum Richards, 1938.

Kenya: Mt. Elgon, heath zone 10,500-11,500 ft., g 2 92 11.35 (F. W.

Edwards).

This species was previously known from two males captured on Mt. Elgon

by Dr. R. Jeannel.

Female. Longer (length 2-5 mm.) but not much broader, abdomen about

three times as long as broad. Cerci finger-shaped, black, with two long and one

short, rather woolly bristles.

Keys to the six species of Ocellipsis Richards and the three species of

Paraptilotus Richards, all confined to Mt. Elgon, will be found in Richards,

1938. Fig. 5 shows the appearance of O. verruciger Richards, one of the species

not obtained by Dr. Edwards.

TWOxOTHER NEW. APTEROUS .SPHAEROCERID GENERA

FROM:THE ETHIOPIAN: REGION

Aubertinia new genus.

Wings and halteres absent. Eyes large. Central pair of interfrontal bristles

enlarged, crossing; only two superior orbital bristles on each side, an anterior

one curving outwards and a posterior one curving inwards; external occipitals

and inner verticals present but weak. Mesonotum as broad as head with eyes;

one strong notopleural bristle; scutellum semicircular with four strong mar-

ginals; one very long sternopleural. Mid-tibia with strong bristles. Abdomen

narrower than thorax; sternites not broad; first tergal plate (=I+I1) not

narrowed at base to form a neck and without a raised lateral margin.

Type of genus Aubertinia sanctaehelenae sp. n.

Aubertinia sanctaehelenae sp. n. (Fig. 7)

Male. Head except eyes and bristles dull yellow; thorax shining yellow,

margins of mesonotum (especially at humeri) and scutellum (especially pos-

teriorly) dark brown; pleuron brownish-black with a small yellow longitudinal

stripe at top, and a broader whitish yellow one across top of sternopleuron; legs

yellow-brown with femora darker; abdomen shining black,

. Length 2:2 mm,

BRACHYPTEROUS SPHAEROCERIDAE 839

Head with mouth-cavity moderately large, mouth parts and palpi normal;

vibrissa moderately long, bristles along oral margin a little longer than usual,

those nearest the vibrissa one-quarter its length, jowls otherwise with only

microscopic hairs; jowls very narrow in front, ‘half width of third antennal

segment, very broad posteriorly but posterior margin shorter than vertical ,

diameter of eye, oral margin scarcely bordered, angle between it and back of

Fics. 4-9.—General dorsal views, microchaetes omitted: (4) Ocellipsis cyclogastey Richards,

type 2 (abdomen a little distorted); (5) O. vevrucigey Richards, type 9: (6) Pavaptilotus

chaetosoma Richards, type §; (7) Aubertinia sanctaehelenae Richards, type 3; (8) Lobeliomyia

scotti Richards, type 9; (9) Howichia trilineata (Hutton) g. Scale line equals 1:0 mm.

840 RUWENZORI EXPEDITION

head rounded; eyes large, subcircular, longitudinal diameter only a little longer

than vertical one, margin with a very small emargination just above level of

antennae, lower margin rounded, ocelli present; face somewhat white-dusted,

moderately diverging, second segment distally with long bristles (some longer

than the third antennal segment), third segment oval, arista dorsal, three times

as long as antennae, with short pubescence; vertex dull, bristle-bearing areas a

little more shining, central triangle very narrow, more than twice as long as its

posterior width, reaching to frontal suture; four or five pairs of interfrontals,

second pair from behind enlarged (as long as antennae) and crossing; on each

side two superior orbitals (one directed outwards and one inwards), one external

vertical, one weak external occipital, one weak inner vertical, one strong ocellar ;

postocular hairs very weak, in a single row.

Mesonotum as broad as head with eyes, subrectangular with rounded angles,

normally convex, humeral and postalar calli not defined, suture and prescutellar

depression normal, on each side with one moderate humeral, one strong noto-

pleural, one supra-alar, two postalars, one strong and two very weak dorso-

centrals behind the suture; microchaetes numerous in rather irregular rows

(about sixteen between the prealars); scutellum about semicircular, anterior

margin,a little wider than median length, with four strong marginal bristies of

about equal size (about one to one and a half times as long as anterior margin of

scutellum) ; pleuron bare except for one very strong sternopleural bristle, nearly

long enough to reach up to mesonotum.

Legs. Fore femora not thickened, with regular dorsal and ventral rows of

long bristles, tibia with short pubescence only, tarsi with first four segments

together as long as tibia, basitarsus as long as next two segments together ;

mid-trochanter with a rather short bristle; mid-femur ventrally with an anterior

row of about twelve minute, but rather stout bristles on basal half, and a row

of four similar posterior bristles on basal quarter, anterodorsally with a row of

about eight short bristles on distal two-thirds, a little beneath at apex two strong

anterior bristles; mid-tibia a little curved—dorsally with a pair of strong bristles

at a quarter, the anterior one surmounted by a minute one, a pair of strong

bristles at two-thirds (the posterior one a little the longer) and a very strong

dorsal at three-quarters—ventrally with an anterior comb of very short black

bristles on distal half, and a strong apical bristle ; mid-tarsi without bristles, half

as long again as tibia, basitarsus a little shorter than next two segments

together; hind femur and tibia without bristles, latter without apical spur;

second segment of hind tarsus little thickened, about one and a half times as

long as basitarsus, shorter than next two segments together.

Abdomen a little narrower than the thorax and about as long as mesonotum

with the scutellum; first tergal plate (=I-+I1) about quadrate, only alittle longer

than third tergite, fourth a fraction shorter than the third, fifth very short, sixth

not visible; tergites without sharp lateral margins, covered with rather numerous

BRACHYPTEROUS SPHAEROCERIDAE 841

microchaetes, a row of which at apices of tergites is rather larger but quite

recumbent; sternites apparently normal, not very broad, not far sunk in

beneath tergite, geriitalia small, without long bristles, details hidden.

Female. Similar ; mid-femora without the modified ventral bristles near base;

mid-tibia less curved, with no apico-ventral comb, abdomen rather longer, fifth

tergite nearly as long as fourth, cerci black, each with a short apical hair.

ST. HELENA: ¢ type, @ allotype and 1 g 1 @ paratypes; B.M. 77-104

(collector unknown; purchased from T. V. Wollaston). The specimens are

all gummed on cards.

Lobeliomyia new genus.

Wings and halteres absent. Eyes large, central pair of interfrontals not

enlarged; head with three superior orbitals, one external vertical and one inner

vertical bristles fully developed on each side. Mesonotum a little narrower than

head with eyes; one very strong notopleural bristle, scutellum twice as broad as

long, with four widely spaced bristles only; no sternopleural bristle. Mid-

tibia with weak bristles only. Abdomen nearly circular, about two and a

half times broader than the thorax; sternites very broad, not deeply sunk into

the tergites; first tergal plate not conspicuously constricted basally to form a

neck, and without a lateral margin.

Type of the genus Lobeliomyra scotti sp. n.

_Lobeliomyia scotti, sp. n. (Fig. 8)

Female. Shining black; antennae black-brown; legs brownish-testaceous.

Length 2-7 mm.

Head with mouth-cavity moderately large (as in Leptocera), mouth parts

apparently rather large, palpi not visible; vibrissa rather long, a row of fine hairs

along the oral margin, those nearest the vibrissa hardly one-quarter its length,

jowls otherwise bare; jowls rather dull, finely striate, at vibrissal angle as broad

as height of third antennal segment, about twice as broad at posterior margin;

oral margin with very indistinct raised border; eyes about normal, oval, longi-

tudinal diameter about one and a half times as long as the vertical one which is

as long as posterior margin of the jowls; upper margin of the eye broadly but

shallowly emarginate; ocelli small but distinct; face shining, mouth-edge

somewhat prominent, facial ““knob’’ not developed; antennae with third

segment oval, apex dorsally a little pointed, arista inserted a little before the

apex, probably about three times as long as the antenna, with short pubescence ;

vertex with orbits posteriorly and central triangle shining, intervening space dull

and dusted; central triangle long and narrow, reaching frontal suture anteriorly,

NN EEE OO OO eee

842 RUWENZORI EXPEDITION

nearly three times as long as its breadth at the ocelli; head on each side with the

following bristles, three very weak adfrontals, two weak anterior, outwardly

directed superior orbitals, one strong posterior, inwardly-directed superior

orbital, one strong outwardly-directed external vertical, one very weak external

occipital (inner vertical absent), one strong ocellar, postocellars very weak and

sparse.

Mesonotum in dorsal view subquadrate, a little broader than long, a little

narrower and hardly so long as the head with eyes, surface shining, a little convex,

suture, humeral and postalar calli nearly obsolete, depression in front of the

scutellum rather deep and narrow, bristles present on each side (as far as they are

still decipherable) are, one weak humeral, one very weak presutural interalar,

one very strong notopleural (fully as long as half width of mesonotum), one

strong dorsocentral just in front of scutellum, surface further with about sixteen

irregular rows of rather widely spaced microchaetes; scutellum very small and

transverse, about two and a half times as broad as long, apparently with a pair

of small basal and apical bristles which are not closely approximated to one

another; mesopleuron mostly dull and tomentose (almost woolly) with large

shining area on the “‘mesopleuron”’ (dEs2) and a narrow one on the pteropleurite,

sternopleural bristle apparently absent; central part of the mediotergite (so-

called “‘metanotum’’) practically obsolete.

Legs with fore femur a little thickened, with short bristles only, tibia without

bristles, pubescence short, tarsi a little longer than tibia, basitarsus as long as_ |

next two segments together; mid-femur without bristles except anterior one

before apex, mid-tibia with a weak antero-ventral bristle at three-quarters, a

weak dorsal bristle at just before apex and a weak apico-ventral bristle; tarsus

as long as tibia, basitarsus as long as next two segments together, without

bristles; hind femur a little thickened, femur and tibia without bristles, the

latter without apical spur, second tarsal segment not thickened, about one

and two-thirds times as long as basitarsus.

Abdomen very large, subcircular (a little longer than broad), dorsal surface

feebly convex, hardly more constricted basally than usual, widest at middle of

second tergal plate (=JII), first tergal plate (=1-+]I) at apex two and a

half times as broad as thorax, its median length about equal to that of meso-

notum; tergite III about two-thirds as long as I+-II but a little broader, tergites

IV and V successively a little shorter and narrower, VI just visible as a narrow

strip, half basal width of V, VIII not visible; first five tergites with sharp edges

but without a raised border; sternites very broad, not deeply sunk into the

tergites, lateral connecting membrane very narrow, first four plates (I--I], III,

IV and V) well-developed, shining, with sparse pubescence; sixth sternite very

narrow, apparently dull; seventh sternite just visible, cerci fused into a little

plate bearing four very long woolly hairs; tergites shining, weakly alutaceous,

with sparse microchaetes in three to four transverse rows. ;

BRACHYPTEROUS SPHAEROCERIDAE 843

ABYSSINIA: Mt. Chillalo, moorland ca. 12—-13,000 ft., 21.ix.26, from decaying

stem of Lobelia (H. Scott), 9 type.

The specimen is not in quite perfect condition, especially as regards the

bristles. It is probable that there are really two additional bristles on each side

behind the notopleural (i.e. supra-alars).

OTHER GENERA WITH APTEROUS OR BRACHYPTEROUS SPECIES

1. Copromyza (Apterina) pedestris (Meigen) of W. Europe has quite short

wings, much too reduced for flight. It is usually found on the ground in marshy

places. Guibé (1939) made a detailed study of it. He found a gene which

controlled wing-development. The dominant brachypterous and the brachy-

pterous heterozygote were the only types found in nature. The macropterous

mutant had wings of variable length and appeared to be slightly less viable.

|e!

10 i : : d eee

Fic, 2e.—General dorsal view, microchaetes omitted, of Anatalanta apteva Eaton 9. Scale

line equals 1-0 mm,

844 RUWENZORI EXPEDITION

2. Speomyia absoloni Bezzi, 1914 and Paraspeomyia hungarica Duda, 1930

may possibly be the male and female, respectively, of one genus, though the

species are probably not the same. They are both known from single specimens,

the first found in a cave in Jugoslavia, the second in a cave in Hungary. The

reduction of the eyes is much more marked than that of the wings. They are

closely related to Copromyza, hardly indeed more than subgenera of it, but the

combination of postvertical bristles with a row of bristles on the mid-tibia is

distinctive.

3. The four antarctic genera Antrops Enderlein 190ga, Penola Richards 1941,

Siphlopteryx, Enderlein 1909b, and Anatalanta Eaton 1875 (Fig. 10). The first,

discussed by Richards (1931: 73), is the least modified and can probably be

derived from the fully-winged genus, Archiborborus Duda, 1921, of the more

northern parts of that region. The single specimen of Penola eudyptidis Richards

was found in the nest of a Penguin but this may not be significant. The other

forms are not recorded to live in special habitats, though they must be exposed

to extreme climatic conditions. I have not been able to examine Siphlopteryx.

4. The New Zealand species, recorded as A pierina trilineata Hutton, 1901.

This species clearly has no affinities with A pteyina Macquart, 1835, but belongs to

an undescribed genus.

-Howickia gen. n.

Wings absent. Halteres small but stalked. Eyes large, longitudinal about

one and a half times vertical diameter, a small but quite deep dorsal emargina-

tion, ventral margin only slightly sinuate. Ocelli absent. Vertex with three

raised silvery lines, no orbitals, strong external vertical and ocellar bristles.

Mesonotum a little broader than head with eyes, one and a half times as broad

as long, subrectangular, one small humeral, one strong notopleural, one strong

prealar, one small and one moderate postalar, one strong prescutellar dorso-

central bristle each side, many rows of microchaetes; scutellum only separated

from mesonotum by a very superficial suture, except for a subcircular pit at each

side, more than twice as wide as long (much less than semicircular) but posterior

margin rounded, four widely spaced bristles, nearly twice as long as scutellum.

Mid-tibia with strong dorsal bristle at one-third, and apparently some more at

two-thirds, apico-ventral bristle very short, basitarsus with no long bristles.

Hind tibia with no bristles or spur. Abdomen nearly circular, very convex,

about as long as head and thorax, one and a half times as long as broad, margins

of tergites sharp-edged but not raised, deflexed; sternites very broad, moderately

sunk into the tergites; first tergal plate (=I- II) very little contracted anteriorly ;

abdominal bristles all short. :

Type of the genus Apterina trilineata Hutton (Fig. 9).

BRACHYPTEROUS SPHAEROCERIDAE 845

There are three male paratypes from near Auckland, Howick (Capt. Brown),

in the British Museum (N.H.). The genus is almost certainly derived from

Leptocera Olivier.

5. Brachypterous species in Leptocera Olivier, 1813. In the very large cosmo-

politan genus Leptocera Olivier brachypterous species occur in seven subgenera.

In the subgenus Limosina Macquart, 1835, there are three species, L.

pseudomivalis (Dahl, 1909), L. manicata (Richards, 1927) and L. meijerei (Duda,

1918). All three seem to be associated with the runs of moles and of rodents in

Western Europe. The first is the most modified, the second the least (the wings

sometimes practically normal); the third is derived from a different species

group to the first two (see Richards, 1930: 332).

_. The subgenus Puncticorpus Duda, 1918, with one species L. (P.) cribrata

(Villeneuve, 1917) is considerably more modified and is not close to any fully

winged species. In its wide, flattened, punctured abdomen with broad sternites

and in the small head-bristles, it shows some approach to the more modified

species. It appears to be an inhabitant of the runs of rodents.

Subgenus Pieremis Rondani, 1856

L. (P.) nivalis (Haliday, 1833) of Western Europe and three North American

species described by Spuler (1924b) (Alaska, Wyoming, Virginia), have the

wings too short for flight, with the intermedian cross-vein absent, but they are

quite close to the fully-winged L. (P.) fenestralis (Fallen, 1820). The European

species occurs, in Britain, chiefly in the runs of rodents.

Subgenus Americaptilotus subg. n.

Wings represented by a very small thickened pad, a little longer than half the

length of the scutellum. Halteres represented by minute, yellow, almost sessile

knobs. Eyes almost normal. Ocelli present. Head with three interfrontal, one

ocellar, three or two superior orbitals (the anterior one being small or absent),

no postvertical, one inner vertical, one very weak external vertical, one very

weak or no external occipital bristle, on each side. Mesonotum a little narrower

than head with eyes, one short humeral, one short notopleural, one short pre-

sutural, one prealer, one very long and one short postalar, two dorsocentral

bristles, on each side. Scutellum about as long as broad with four widely spaced

long bristles. One moderate sternopleural bristle. Mid-tibia with an antero-

dorsal bristle at one-third, a rather longer dorsal at two-thirds with a small

anterodorsal just above it, and a very short apico-ventral in female only. Mid-

tibia without bristles or spur. Abdomen little modified, tergal plates I4-I1 with

846 RUWENZORI EXPEDITION

sharp edge but no raised margin; sternites broad; abdomen not constricted

anteriorly; no long tergal bristles.

Type of subgenus Afptilotus borealis Malloch, 1913.

Besides the type species (Wyoming, Montana), there is a second one, A pierina

polita Williston, 1893 (New Mexico). They have been referred by Spuler (1924a)

and others to A ftilotus Mik but, as seen from the key (p. 847) are considerably

less modified. I have been able to examine specimens of both of them owing to

the kindness of the authorities of the U.S. National Museum and of Mr. J. R.

Malloch.

Enderlein (1938) described three monotypic genera from the island of Juan

Fernandez, off the pacific coast of S. America. I have not seen these species.

The wings are much reduced, though some of the venation is preserved, but the

halteres and ocelliare normal. I consider that Skottbergia cultellipennis Enderlein,

Phthitia venosa Enderlein, and Pterodrepana selkirki Enderlein are best regarded

as forming subgenera of Lepftocera Olivier. The first named, with its eight

scutellar bristles, five pairs of dorsocentrals the front one of which is not directed

inwards, and strong bristle on the mid-trochanter, might well be put in what I

have called the typical subgenus of Leptocera (=Paracollinella Duda, 1923).

Vimmer (1929) described a reputedly brachypterous species from Czecho-

Slovakia, Aptilomyia vStetkat. Dr. Vimmer was kind enough to lend me the

type of his species, and it is a specimen of Leptocera claviventris (Strobl, 1909) in

which the wings have been broken off near their bases and one haltere is missing.

A ptilonyia, therefore, becomes a synonym of the subgenus Limosina Macquart,

1835, and the trivial name falls to that of Strobl (syn. n).

6. Aptilotus Mik, 1898.—Wings and halteres absent. Eyes somewhat small,

shallowly emarginate below. Ocelli small but distinct. Three equal interfrontal

bristles, one ocellar, three superior orbitals, one external vertical, one external

occipital (all rather short and thick).on each side. Mesonotum a little narrower

than head with eyes, one very weak humeral, one notapleural, one very weak

prealar, one supra-alar, one rather long postalar, one very weak prescutellar

dorsocentral bristle, on each side, scutellum small, transverse, twice as broad as

long, with minute lateral and small median bristle on each side; one short

sternopleural bristle. Mid-tibia with a weak antero-dorsal bristle at one-quarter

and one at three-quarters, a dorsal a little lower, and a weak apico-ventral.

Hind tibia without bristles or apical spur. Abdomen moderately convex, oval

in dorsal view, scarcely more constricted anteriorly than usual, first five tergites

with sharp but not raised margins; sternites broad, little sunk into the tergites;

abdominal bristles all short. Type of the genus (monobasic), Aptilotus pavadoxus

Mik, 1808.

I have examined Mik’s type male from Hungary (Hermannstadt, 20.vii.1898) |

and a female from Austria (Konigstuhl district, subalpine, Holdhaus) kindly

lent to me by Dr. Zerny of the Naturhistorische Museum, Wien. Vimmer (1929)

BRACHYPTEROUS SPHAEROCERIDAE 847

described a second species, A. voubali, from Czechoslovakia, but an examination

of the type, kindly lent to me by Dr. Vimmer, shows that it is the same as Mik’s

species (Syn. n).

There is nothing so far recorded in the habits of this species to account for its

wingless condition.

7. Duda (1929) described a new genus and species as A ftilotella borgmetert.

It was very small (length 0-9 mm.), without wings, halteres or ocelli, and the

structure in many ways very specialised. The antennae have the third segment

pointed with a subapical arista, as in the fully-winged species of Anommonia

Schmitz, 1917, found with ants in Africa. The present species of which a single

male has been found in Brazil may also be a myrmecophile.

A KEY TO THE BRACHYPTEROUS AND APTEROUS GENERA OF SPHAEROCERIDAE

Leal

Wings and halteres present, at least as rudiments . ‘ : : : ; 2

— Either wings or halteres, or both, completely absent : : : : ADIN to)

2 Eyes strongly reduced. Wings not very short, with complete venation, Mr+2

extending as a thick vein to margin, cross vein 7m near margin. Hind tibia

with no apico-ventral spur. Cave species

— yes normal : F : . : : : 4

3 Ocelli absent. (Jugoslavia.) Speomyia Bezzi. S. absoloni Bezzi.

— Ocelli present. (Hungary.) Pavaspeomyia Duda. P. hungarica Duda.

4 Ocelli and ocellar bristles absent. Scutellum very narrow with two upwardly-

directed bristles. Hind tibia with a curved apical spur. (Antarctic.) Antyvops

Enderlein. A. truncipennis Enderlein.

— Ocelli present. Scutellum with at least four bristles: . . . J . 5

5 Hind tibia with a curved apico-ventral spur. Scutellum transverse with four

erect and some smaller bristles. Wing venation very reduced, wing rounded.

Halteres small. Head behind the eyes with numerous small bristles; Europe

Copromyza Fallen (subg. A ptevina Macquart). C. pedestyis (Meigen).

— Hind tibia with no apico-ventral spur. Scutellum with at least four resupinate

bristles. Head behind the eyes with one row of bristles. Leptoceva Olivier : 6

Wings pointed with venation crowded into costal egion ies nae

— Wings rounded or reduced and pad-like

7 Mid-trochanter with a strong bristle. Scutellum with eight preace Five pairs of

dorso-centrals, anterior pair not directed inwards.

Subg. Skottbergia Enderlein. L. cultellipennis (Enderlein).

— Mijid-trochanter with no strong bristles. Scutellum with four to six bristles. Fewer

dorso-centrals : : é 8

8 Scutellum with four bristles. ie Phthitia Pnderlein. L. venosa fendedemn\:

— Scutellum with six bristles. Subg. Ptervodvepana Enderlein. L. selkivki (Enderlein)

9 Wings veinless pads, only half as long as scutellum. (North America, two species.)

Subg. Americaptilotus Richards.

— Wings extending beyond the scutellum with distinct venation of the Leptoceva-

type (Mi-+2 not reaching the margin as a thick vein, cross vein im far removed

fon)

from margin) : : : c : ¢ : : . : SAE LO

10 Cross vein im absent. (One species Europe, three N. America.) Subg. Prevemis

Rondani.

— Cross vein im present : II

ir Abdomen flattened and strongly se rceited: Paoee Sube: Piniicorbus Dada.

L. cribrata (Villeneuve).

— Abdomen normally convex, not punctured (three brachypterous species, Europe).

Subg. Limosina Macquart.

RUWENZORI EXPEDITION

Traces of wings present, halteres absent. Three rather reduced ocelli present

Wings completely absent

Scutellum very narrow and transverse. Wings (2) narrow, almost thread-like,

but reaching beyond scutellum. Abdomen flattened, not much narrowed

anteriorly, posteriorly truncate. (Falkland Is.) Penola Richards. P. eudyptidis

Richards. : : ; : : 0 : . c : : é

Scutellum approximately semicircular,

Wings small and scale-like in both sexes. Abdomen oval. (Crozet Is.) Siphlopleryx

Enderlein. S. antarctica Enderlein.

Wings in 2 present as minute scales only half the size of the third antennal

segment; in ¢ oval, as long as width of head between the eyes, with costa and

one other vein. Abdomen egg-shaped, tergite—one considerably narrowed,

tergites with macrochaetes. (Mt. Ruwenzori.) Aluligera Richards. A. montana

Richards.

Halteres present though rudimentary. Top of head flattened with three lines of

silvery tomentum, only interfrontals, external verticals and ocellar bristles

present. Eyes normal, ocelli absent. Scutellum not much reduced, but posterior

margin nearly straight. Abdomen circular, sharp-edged. (New Zealand.)

Howickia Richards. H. tvilineata (Hutton).

Halteres absent . : c :

Scutellum normal, about semicircular, with four long bristles. Abdomen little

broadened, usually broadest before middle and tapering posteriorly. Mesonotum

about as broad as head with eyes. Ocelli normal, ocellar bristles well-developed

Scutellum at least twice as broad as long, the bristles often very short. Abdominal

sternites broad or very broad, tergites without macrochaetes. In Mesaptilotus

the scutellum is intermediate, but at least the anterior ocellus is absent or

very reduced.

Abdominal sternites very broad, abdomen long oval, margins sharp but deflexed,

tergites with long macrochaetes. Two superior orbitals. Interfrontals all

small. (Mesaptilotus Richards which might seem to run down here, has median

ocellus at least very small and abdomen with no macrochaetes.) (Kenya,

Aberdare range.) Binorvbitalia Richards. B. nitidissima Richards.

Abdominal sternites narrow, abdomen of normal shape, margin not sharp-edged.

Three superior orbitals. Interfrontals all small. Abdominal tergites with long

macrochaetes. (Mt. Elgon, 3 species.) Paraptilotus Richards.

Two superior orbitals. Central pair of interfrontals enlarged, crossing one

another. (St. Helena.) Aubertinia Richards. A. sanctaehelenae Richards.

Scutellum somewhat reduced but still nearly semicircular with four quite long

bristles. Ocelli absent or lateral ones present but small, or median also present

but very small. Two superior orbitals, an external vertical, and an ocellar

bristle on each side. Mesonotum hardly narrower than head with eyes.

Abdomen oval, margins sharp, sternites very broad. (Mt. Ruwenzori.) Mesa-

ptilotus Richards. M. pollinosus Richards.

Scutellum very short and much broader than long, with not more than one pair

of long bristles

Three ocelli present, even if somewhat reduced. Three superior orbitals, an

external vertical, and an ocellar bristle on each side. Mid-tibial bristles weak

Ocelli absent. Superior orbitals and vertical bristles absent. Abdomen circular,

sternites abroad

Outer pair of scutellar bristles at least twice as long as scutellum. Abdomen oval,

with short anterior stalk, about two and a half times wider than mesonotum,

which is:a little wider than head. (Kerguelen and Crozet Is., 3 spp.)

Anatalanta Eaton.

Scutellar bristles not much longer than scutellum. Abdomen not stalked.

Mesonotum a little narrower than head with eyes

Abdomen of normal shape, about one and a half times as broad as thorax, not

sharp-edged, sternites rather broad. Prescutellar pair of dorso-central bristles

short. (C. Europe.) Aptilotus Mik. A. pavadoxus Mik.

BRACHYPTEROUS SPHAEROCERIDAE _ 849

— Abdomen circular, two and a half times as broad as thorax, sternites very broad.

Prescutellar pair of dorso-central bristles long. (Abyssinia.) Lobeliomyia

Richards. L. scotti Richards.

23 No ocellar bristles. Head normal, third antennal segment rounded. Two or four

scutellar bristles, outer pair much longer than the seutellum. (Mt. Elgon and

Elgeyo escarpment, 6 species.) Ocellipsis Richards. .

— A pair of divergent, backwardly directed ocellar bristles. Head co-adapted to

thorax. Third antennal segment conical. Six very small scutellar bristles.

(Brazil.) Aptilotella Duda. A. borgmeievi Duda.

THE CLASSIFICATION OF THE WINGLESS SPHAEROCERIDAE

Bezzi (1917, 1922) has published lists of the flies known to have their wings

reduced or absent, and in the earlier paper noted the environmental conditions

under which such flies seem to be most common. The three principal types of

habitat in which brachypterous or apterous species are most often found are:

(x) Places which provide unusually good shelter without the opportunity for

much flight such as bases of dense growths of Gramineae or Cyperaceae, runs of

small mammals, nests of ants, wasps or termites, caves. (2) Places with a severe

climate and, especially, strong winds such as intertidal areas, alpine regions,

treeless antarctic islands (but not oceanic islands in general). (3) The external

surface of Vertebrates, inhabited by many Pupipara. Apparently all the

brachypterous or apterous species discussed in the present paper of whose

habitat anything is recorded live in one or other of the situations listed under

1 or 2. The Ethiopian species in particular are all found at altitudes of about

12,000 ft. in a climate which is probably rarely favourable for the flight of small

insects. Bezzi has noted that wing-reduction may take place anywhere in the

world in suitable environmental conditions, though of the 1g completely wing-

less species of Sphaeroceridae, 1m are found on the mountains of tropical

E. Africa. Loss of wings leads to consequential changes in other parts of the

body until ultimately nearly all the characters normally of generic importance

in the family are affected.

Thus the halteres become reduced or absent, especially in completely apterous

forms. This is not surprising since Pringle (1949) has shown that the halteres act

as gyroscopic organs controlling sideways turning in flight; it would perhaps

have been rather expected that more of the short-winged species which hop

but never fly should have lost them. There is a marked tendency (18/39 species)

for the scutellum to be shortened, eventually becoming narrow and transverse

with only small bristles. The mesonotum also becomes smaller, narrower than

the head or abdomen, though this feature is less easy to assess quantitatively.

Ocelli are absent or markedly reduced in 12 out of the 39 species, and only one of

these is an inhabitant of caves. The function of these organs is uncertain so that

the significance of the change is doubtful. There is a slight tendency, also, for a

reduction of the eyes, apart from two cave-species. The perimeter of the eyes is

often emarginate, especially above. In most of the more modified forms the

850 RUWENZORI EXPEDITION

abdomen tends to become oval or circular, with sharp margins, and with a slight

neck where it is attached to the thorax; the sternites become broad. This,

combined with the narrow mesonotum, gives such genera a very characteristic

appearance. Finally, there is a tendency for many of the bristles to be reduced

in size and number. The ocellar bristles usually go with the ocelli, and the

scutellar bristles with the scutellum, and sometimes other bristles are markedly

reduced. The legs show no marked changes, apart from some reduction of their

bristles. The distribution of the more important of these characters is shown in

Table I.

TABLE I

Wings Halteves Scutellum | Ocellt Abdomen

20+ 17+ ig 15+ @ ‘T4+ 14 N

| \ ort < < I— IN

UI 2+ & I+ ae IN

(| I— IN

3— 2+ < 2+ 20

iS | le 1O

.I9— | T+ t+ t= ( TG

6 5 (| Sat: | 4N

| <

| | | q 10

LO ae <0 (| 44+ | IN

| 1S) Ee | fike3/0

| < I [Saen.03@)

L 8— 8 Oor C

Explanation of Table I

Character of wings, halteres, scutellum, ocelli and abomen in the 39 species of apterous

or brachypterous sphaeroceridae. + = normal; -- = reduced;—= absent. In the abdomen:

N= normal (i.e. posteriorly narrowed); O= oval; C= circular.

It is clear from this summary: (1) that there is a general tendency for increas-

ing and correlated specialisation (mostly reduction), (2) that there are neverthe-

less many exceptions where one part is more reduced than the others; e.g.

Howickia has halteres but no wings and a normal scutellum but no ccelli,

(3) that the apterous species are more modified (apart from wings) than the

brachypterous ones.

It is clear that the reductions must have taken place on numerous separate

occasions. Even in the African region there is no reason to think that any one

of the apterous genera has been derived from another. It would seem, therefore,

that the correct taxonomic arrangement is either to put all the species in the same

genera as their probable fully-winged ancestors, though it would be difficult to

do this for such forms as Anatalanta of which the ancestor is doubtful, or else to

put each set of species in a distinct genus or subgenus, as has been done here.

BRACHYPTEROUS SPHAEROCERIDAE 851i

The species in which vestiges of wings have been retained are nearly all much

less modified, and many of them can be derived with certainty from a fully-

winged genus, often from a particular section of it. These forms have only been

separated subgenerically. The apterous species, nearly always with marked

changes in all parts of the body and in all the characters normally used in

classification, have had to be placed in separate genera. No doubt most of them

are ultimately derived from Leptocera but the differences are very marked, and

are almost certainly irreversible.

REFERENCES

Papers up to about 1929 will be found in the bibliography in my paper on the British

species (Richards, 1930). They are not separately quoted here.

Bezz1, M. 1917. Riduzione e scomparsa delle ali negli insetti ditteri. Riv. Sci. nat.

“Natura”, 7:85-182, 11 figs.

Dupa, O. 1929. Aptilotella borgmeiert g, eine neue fliigellose Borboride (Dipt.) aus

Brasilien. Natuurh. Maandbl., 13:74-76, 1 fig. 1938. Sphaeroceridae in EF. Lindner “ Die

Fliegen”’, lief. 177:1-48, 3 plates, ro figs.

ENDERLEIN, G. 1938. Die Dipterenfauna der Juan-Fernandez und der Oster-Iusel. in

“The natural history of Juan Fernandez and Easter Island’, 3:643-80, 49 figs., Stockholm.

GuiB£, J. 1939. Contribution a l'étude d’une espéce: A plevina pedestvis Meigen (Diptére).

Bull. biol. France et Belg. Suppl. 26: pp. 112, 3 plates, 33 figs.

PRINGLE, J. W. S. 1949. The gyroscopic mechanism of the halteres of Diptera. Phil.

Trans. Roy. Soc., 233B:347-84, 1 plate, 22 figs.

Ricuarps, O. W. 1930. The British species of Sphaeroceridae (Borboridae, Diptera).

Proc. Zool. Soc. London, 1930:261-345, 1 plate.

—————. 1931. Sphaeroceridae (Borboridae) in Dipteva of Patagonia and South Chile.

Part 6, fasc. 21. London, British Museum.

———. 1938. Diptera. Sphaeroceridae (Borboridae, Cypselidae) 7m Mission Sci. de

V’Omo, 4 fasc. 40:381-405, Io figs.

———. 1941. Sphaeroceridae (Diptera) in British Graham Land Expedition 1934-37.

Sci. Rep., 1, No. 7:323-26, 1 fig.

VIMMER, A.1929. Zwei neue fliigellosen Dipteren—Fam. Cypselidae. Acta Soc. ent. Cech:,

26:64-68, Io figs.