List of Fascicles issued to 22nd November, 1930 Kentanteny —

Part IV. CoLEropTerA.

Fase. |. Carabide. By H. E. ree 9 text-figures. Dytiscide. By A.

Zimmermann. 2 cena arty linide. By M. Cameron, MB. 2 text-

figures. Hydrophilide. By A Orch

Lamellicornia. By G. J. ree reall 927, 4io. 3s.

Fase. 2. Heteromera, Bostrychoidea, Malacodermata a Nee ne By K. G.

Blair, BSc. 14 text-figures. ateride. By R. H. van Zwaluwenberg. 10

text-figures. Actes ES NORE By E. Fleutiaux. rambycide. By

Chr. ae i late. ae hide. By R. Klee. 4 text-figures.

Anthribide. Kark ordan, Ph.D. 11 text-figures. Proterhinide. By

RECRE te. By Ken -R.S. Pp. 67-174. 1928, 4to. 5s.

Fasc. 3. Throscide. By K. G. Blair, B.Sc. 1 text-figure. Chrysomelids.

By S. Maulik, M.A. 18 text-figures. Pp. 175-215. 1929, 4to. 2s, 6d.

Fasc. 4. Platypodidae and Scolytidae. By C. F. C. Beeson, D.Sc. 13 text-

figures. Pp. 217-248. 1929, 4to. 2s. 6d.

Part V. HYMENOPTERA.

Fase Apoidea, Sphecoidea, and Vespoidea. By R. C. L. Perkins, DSc,

and _L, Evelyn Cheesman, F.E.S., F.Z.S. 12 text-ficures. Larride.

By Francis X. Williams. 12 text-figures. Formicidz. By Dr. F. Santschi,

9 text-figures. Pp. 1-58. 1928, 4to. 5s. ~

Part VI. Drprera.

Fasc. 1. Streblide and Nycteribiide. By L. Falcoz. 7 text-feures. Hiece

boscide. By G. F. Ferris. 6 text-figures. Pp. 1-21. 1927, 4to. 2s. 6d.

Fasc. 2. Nematocera. By F.W.Edwards, M.A. 20text-figures. Cecidomyiine.

By H. F. Barnes, B.A., PhD. 4 text-figures. Pp. 23-108. 1928, 4to. 5s.

Fasc. 3. Stratiomyiide, Tabanide and a By Gertrude Ricardo. 6 text-

sures. Larve of Stratiomyide. . A; Buxton, MLA. 2 text- ane

Dolichopodide. By C. G. Lamb, SED. 8 text-figures. Sarcophagide.

P. A. Buxton, M.A. 9 text-figures. © Muscide. By J. R. Mailoch.

Pp. 109-175. 1929, 4to. 5s.

Fasc. 4. Empididae and pees By Jj. E. Collin. 7 as

Syrphidae. By Frank M. Hull. Day neues Clustidae (Heteroneuridae)

ape Sea By J.R: Malloch. 6 text-figures. Pp. 177-213. 1929,

Fasc. 5. Ortalidae. By J. R. Malloch. 6 text-figures. Calliphoridae. By

J.R. Malloch. Pp. OG 7 1930, 4to. 2s.

Fasc. 6. Lonchaeidae, Chloropidae and elds, By J. R. Malloch. 3

text-figures. Pp. 239-251. 1930. Is.

Part VII. Ortner Orpers or INSECTS.

Fasc. 1. Isoptera: Family Termitide. By Gerald F. Hill 14 text- Suto and

1 plate. Odonata. By Lt.-Col. F. C. Fraser, IM.S., F.E.S. 5 text-figures.

Pp. 1-44. 1927, 4to. 2s. 6d.

Fasc. 2. Plectoptera. By R. J. Tillyard, Sc.D. (Cantab.), F.RS., and J. A.

Lestage. 2text-figures. Siphonaptera. By uxton, M.A. Thysanoptera.

es Richard S. Bagnall, FRS.E.,F.LS. 6 text-figures. Pp. 45-76. 1928, 4to.

ae 3. Apap By J. Hae r as DSc. 2 text-figures. Anoplura. By

Buxton. MA Trichoptera. By Martin E. Mosely. 1 figure.

aoe By P. Esben-Petersen. 1 text-figure and 2 plates. Apterygota.

By George H. Carpenter,D.Sc. 32text-figures. Pp.77-116. 1928,4to. 2s. 6d.

Part VIII. TerrestriAL ARTHROPODA OTHER THAN INSECTS.

Fasc. 1. Isopoda Terrestria. By Harold G. Jackson, D.Sc. 2 plates. Scor-

pionoidea. By P. A, Buxton, M.A. Pseudo-scorpiones. By A. Kistner.

oe ene Acarina. By Stanley Hirst. 2 text-figures. Pe: 1-27. 1927,

to . Od.

Fasc. 2. Myrionoden (Myriopoda). By C. Attems. 4 text-figures. Araignées

(Araneida). By Dr, Lucien Berland. 79 text-figures. Pp. 29-78. 1929, 4to. 2s. 6d.

Part IX. Summary ANpD INDEx. -

Fasc. 1. Description of the Environment. By P. A. Buxton, M.R.CS. 2

text-figures and 6 plates. Pp. 1-31. 1930, to. 2s. 6d.

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TMe

BRITISH MUSEUM (NATURAL HISTORY) Vs ae / XS, z

INSECTS OF SAMOA

AND OTHER SAMOAN TERRESTRIAL

ARTHROPODA

PART VI. DIPTERA

FASC. 7. Pp. 253-266

TRYPETIDAE

By J. R. MALLOCH,

WITH ONE TEXT-FIGURE

€ es a

5 DEPARTS ENT

2 Tomo?

LONDON:

PRINTED BY ORDER OF THE TRUSTEES OF THE BRITISH MUSEUM

SOLD AT

Tan British Musnum (NaturaL History), CromweLn Roan, S.W.7

AND BY

B. Quaritcx, Lrp.; Dutav & Co., Lrp,; anp Tum Oxrorpd University Pruss,

1931

Issued 28th November, 1931.] [Price One Shilling.

“INSECTS OF SAMOA ~

AND OTHER SAMOAN TERRESTRIAL

. ARTHROPODA | es

. hovel a rongeeaphy or series of pagers devine, Di hionen ait |

the land arthropod fauna of any group of islands in the South Pacific may be

expected to yield valuable results, m connection with distribution, modification ie

due to isolation, and other problems, no such work is at present in existence. _

In order in some measure to remedy this deficiency, and in view of benefits —

directly accruing to the National Collections, the Trustees of the British —

Museum have undertaken the publication of this account of the Insects and other _

Terrestrial Arthropoda collected in the Samoan _ Islands, i 1924-1925, by

Messrs. P. A. Buxton and G. H. E. Hopkins, during the Expedition of the

London School of Hygiene and Tropical Medicine to the South Pacific.

Advantage has been taken of the opportunity thus afforded, to make the studies -

as complete as possible by including in them all Samoan material of the groups _

concerned in both the British Museum (Natural History) and (by cours y: of

the authorities of that institution) the Bishop Museum, Honolulu.

Tt is not intended that Conebata to the text shall be conte to ihe Be

Muscurn Staff or to any one nation, but, so far as possible, the assistance of the

leading authorities on all groups to be dealt. with has been obtained.

The work is divided into mine « Darts” ‘Ge iB 3 of ees ae are. a

subdivided into “ Fascicles.” (Each of the latter, which appear as ready in

any order, consists of one or more contributions. On the completion of the

_systematic portion of the work it is intended to issue (in Part IX) a general

survey, summarising ihe whole and drawing from it ack conclusions as may i

be warranted.

A list of Fascicles ie! ae will be found o on pp. 3 a 4 of this wrapper.

EE. AUSTEN, «3

Ha the | Keeper of Entomology.

British Museum (Natura History), tee

CroMWELL Roan, S.W.7.

NSCs OF SAMOA

Part VI. Fasc. 7

DIPTERA

| TRYPETIDAE

By J. R. Matztocu, Bureau of Biological Survey, Washington, D.C.,

U.S.A.

(With 1 Text-figure.)

THERE is a very strong resemblance between many members of this family and

others belonging to the Ortalidae, but they may be separated from the latter

by the bristling of the frons and pleura, and less decisively by the wing venation.

The frons in Trypetidae has usually one or two backwardly sloped bristles on

the upper third of each orbit, and in front of these two or more incurved bristles,

which are placed closer to the eyes than the upper bristles; the pteropleura

always bears a quite well-developed bristle or numerous strong setulae ; and the

subcostal vein of the wing is abruptly bent forward near its apex, and almost

invariably rather poorly developed from the bend to its junction with the costal

vein. In Ortalidae the orbits are frequently entirely devoid of bristles, and

there are but few cases where an anterior incurved bristle is present ; hairs are

generally absent, and I know no member of the family which possesses a strong

bristle on the pteropleura ; where there is any doubt as to either or both of

these characters, the course of the subcostal vein may be taken as the criterion ;

this is in practically all cases almost straight, converging gradually towards the

costa at its distal extremity, with the tip well developed and distinct.

So far as our information goes, the larvae of Trypetidae are phytophagous,

many feeding in fruits; consequently some of the worst insect pests belong to

the present family. The latter is rather poorly represented in the collection

before me, there being representatives of but three genera and eight species,

VI. 7. 253

254 INSECTS OF SAMOA.

most of which are referable to the genus Dacus sens. lat. Bezzi has recorded a

total of nine genera and fourteen species as occurring in the Fiji Islands ; five of

these species belong to the genus Dacus sens. lat., but some of the records are

based upon the testimony of other workers.

I have included in this paper some records taken from material in the collec-

tion of the United States National Museum.

DACINAE.

Dacus Fabricius.

This genus, which is very widely distributed in the Old World and lacking

in the Americas, is of considerable economic importance, most of the known

species being more or less directly associated with cultivated fruits, in which

their larvae feed. The genus has been divided into several rather unsatisfactory

segregates, which at best can be classed as subgenera. In the present collection,

the greater portion of the species are referable to the subgenus Chaetodacus

Bezzi. As occurring in the Fiji Islands Bezzi has recorded five species, only

two of which were represented among the material from these islands seen by

him. He has given in his “ Diptera Brachycera and Athericera of the Fiji

Islands ” a synoptic key to all the species known to occur in the Pacific Islands

or Australia, of which I have made use in identifying the present collection. I

have also examined the type specimens of certain species described by Coquillett,

which are in the collection of the United States National Museum. Since some

species dealt with in the present paper are not included in Bezzi’s memoir, [|

present below a key to the species known or likely to occur in Samoa.

KEY TO THE SPECIES.

1. Wing with oblique fuscous submedian fascia extending from

fuscous costal striple over both cross veins to hind margin,

and with a similar anal fascia ; scutellum, except a narrow

transverse black basal line, entirely yellow ; a minute black

dot in each antennal fovea close to anterior lower angle ;

abdomen black at base, with ground colour orange-yellow,

and with a narrow central, and on each side of dorsum a

broader vitta, all shinmg deep black; prescutellar, supra-

alar, and pteropleural bristles distinct ; frons with two pairs

of anterior incurved orbital bristles; second visible

abdominal tergite with usual apical lateral fringe in male . distinctus, sp. n.

— Wing without any oblique dark fascia near middle, the anal

one inconspicuous. : : : ; s 5 : 2

TRYPETIDAE. 255

2. Apical free section of anal vein about 1-5 so long as lobe of cell,

7.e. that section of cell from angle to tip ; supra-alar bristle

lacking, prescutellar and pteropleural bristles present ;

sheath of ovipositor cylindrical, glossy black except at base ;

ground colour of abdomen orange-yellow, with a narrow

central vitta and a much broader vitta on each side of visible

tergites 2 to 4 deep black and glossy ; thorax brownish

yellow, glossy, with following ivory yellow marks: humeri,

a narrow vitta on each side of mesonotum behind suture, a

large mark on mesopleura, and a double spot on metapleura,

and in addition two narrow, submedian, densely greyish

pollinose vittae on mesonotum, beginning before suture and

extending a little beyond it ; between these vittae a rather

indistinct black line, while centre of metanotum is broadly

black ; costal streak dark brown, distinct to about midway

between tips of third and fourth veins, not extending over

second vein on to field of wing, and but slightly widened

beyond tip of that vein : . aenrgmaticus, sp. n.

— Apical free section of anal vein not so ene as Hobe of aro cell ;

supra-alar bristle generally well developed: sheath of ovi-

positor usually flattened ‘ : 3

3. Face entirely yellow, without a black spot in each amoneal

fovea . rs : P : 4

— Face with a black sa in lower nerion of sondh antennal fovea 7

4, Anterior cross vein broadly margined with fuscous : . curvipennis Froggatt.

— Anterior cross vein not margined with fuscous

5. Mesonotum and humeri deep black, a small eoaele on

posterior notopleural calli, scutellum except a narrow trans-

verse basal line, a large mark on mesopleura, and a double

spot on metapleura, ivory yellow ; abdomen entirely shining

black ; wing much as in Dacus aenigmaticus, but free section

of anal vein hardly so long as lobe of cell, costal stripe

similar to that in the other species; mesonotum with two

submedian greyish pollinose vittae, extending from anterior

margin to about eee between suture and posterior

margin : . passiflorae Froggatt.

— Mesonotum, haere and ‘gameboy onenela Blacks: ieostal

streak in wing very faint beyond tip of first vein, darker

apically ; inner cross vein slightly clouded, outer one hardly

so in case of type ; legs black, front coxae and bases of front

femora yellowish . : 3 : ‘ . melanotus Coquillett.

— Mesonotum and humeri not entirely Bisel: tdomen largely

yellow : : 6

6. Head, thorax, and silos, entirely mhameye: Fellow: portal

stripe in wing very faint, distinct only along apical margin

of wing between tips of second and fourth veins ;_ both

cross veins slightly clouded; the two anterior pairs of

incurved fronto-orbital bristles yellow, upper reclinate

pair and vertical bristles black 4 : ; : . luteola, sp. n.

256

10,

ll.

12.

13,

INSECTS OF SAMOA.

Head yellow, thorax with large black markings much as in

tryont, pleura and abdomen also with distinct black mark-

ings; scutellum sometimes with fuscous central stripe ;

costal stripe in wing narrow but distinct on entire length

as in ferrugineus, anal stripe pale brown, cross veins not at

all clouded ; all fronto-orbital and vertical bristles black .

. Humeral bristle well developed ; scutellum flattened on disc,

its apex very distinctly concave in outline, apical bristles

situate on slightly protuberant lateral angles ; costal streak

very narrow, dark brown, continued from tip of first vein

to beyond that of third, anal streak almost indistinguish-

able, and no cloud over either cross vein

Humeral bristle undeveloped ; scutellum sometimes slightly

transverse but never distinctly concave at apex, apical

bristles not situate on produced angles

. Scutellum with four bristles

Scutellum with but two bristles, basal pair feeling

. Prescutellar and supra-alar bristles undeveloped ; costal ee

in wing very narrow and rather pale, continued to apex

where it is not at all widened ; anal streak faint ; outer cross

vein not clouded on any part : :

Prescutellar and supra-alar bristles well developed: accel

streak in wing broader, in part extending over disc to third

vein; anal streak very distinct ;

Costal streak much widened from above level of puter cross

vein to apex of wing, carried over disc of wing to slightly

beyond fourth vein and connected with a broad dark cloud

which encloses outer cross vein; legs including coxae

yellow ; lower fronto-orbitals in three pairs

Costal streak not or much less widened apically, never Send:

ing over fourth vein nor connected with a dark cloud en-

closing outer cross vein ,

Costal streak in wing widened spot- ages at sees ional tires

pairs of anterior incurved fronto-orbital bristles present,

two anterior pairs very close together; mesonotum with

central yellow postsutural vitta; femora entirely yellow

testaceous; a faint dark cloud over tip of fifth vein

beyond outer cross vein, not extending upward over latter

Costal streak not at ail or very slightly widened apically ;

mesonotum with or without yellow central postsutural

vitta; femora more or less conspicuously browned or

blackened

Scutellum black, with margin narrowly rellow endl amalantile

similarly coloured ‘

Scutellum yellow, narrowly black across base or Pan Black

apical spot .

Only tips of femora blackened: ree of eeatellarn with black

mark; outer cross vein with all or almost all of its extent

clouded with pale brown

facialis Coquillett.

zanthodes Broun.

cucumis Froggatt.

chrysotoxus Hendel.

caudatus Fabricius.

kirki Froggatt.

bezzvi Miyake.

14.

15.

18.

IS)

TRYPETIDAE.

Femora with more than distal halves black ; outer cross vein

with at most its lower extremity slightly clouded

Femora blackish brown, with yellowish bases, broader in case

of hind pair ; front and middle tibiae yellowish, hind tibiae

black on inside, dark reddish on outer surface ; all tarsi

whitish at base, blackish at tip, front pair with only basal

segment whitish

Front femora almost entirely black, Pallas only at ace and

extreme tip, middle femora also black, but a little more

broadly yellow at base, hind pair with more than basal

halves whitish, remainder black; tibiae blackish, but

middle pair broadly pale in middle; middle tarsi yellow,

the other pairs dark, with basal segment whitish 3

Wings entirely infuscated except some hyaline streaks in basal,

first posterior, and anal cells ; frons clothed with short black

bristles on a blackish blotch just above antennae

Wings much less extensively infuscated; frons without a

group of short bristles on anterior margin

. Outer cross vein of wing very distinctly clouded ; cell Ry wide

apically y

Outer cross vein of wing Ot at all or finely Gleddede eal Ry

narrow apically

. Apical portion of dark costal fein fae enlace! ending

below fourth vein and connecting with dark cloud over

outer cross vein 5

Apical portion of dark costal Pople noe so melt pularced: ree

extending below fourth vein and clearly eee from dark

cloud over outer cross vein

Dark costal stripe extending to third vein andl not dusted

apically, inner cross vein broadly margined. with fuscous ;

face usually without black spots : :

Dark costal stripe not extending to third vein, inner cross vein

not at all or very inconspicuously margined with fuscous ;

face always with a pair of black spots in antennal foveae

Anterior portion of mesonotum yellow, with black median

stripe and black transverse band ; sublateral yellow post-

sutural stripes curved inwards along transverse suture

Mesonotum not coloured as above, postsutural sublateral stripes

when present not curved inward along transverse suture

. Mesonotum shining deep black in front of suture, only humeri

and posterior notopleural callosity yellow

Mesonotum partly reddish or yellowish laterally, or laterally

and centrally in front of suture

. Dark costal stripe on wing very distinct peyoud tip of Sins

vein ; sublateral postsutural yellow vitta on thorax distinct,

stopping at suture

Dark costal stripe on wing very ohn or lacking beyond oo

of first vein ; yellow sublateral postsutura] vitta on thorax

lacking

257

quadrisetosus Bezzi.

scutellaris Bezzi.

pepisalae Froggatt.

chrysotoxus Hendel.

cucurbitae Coquillett.

curvipenms Froggatt.

ornatissimus Froggatt.

Froggatti Bezzi.

258 INSECTS OF SAMOA.

22. Scutellum broadly black in centre, only sides yellow ; humeri

blackened above . : 3 F : . : . psidi Froggatt.*

— Scutellum yellow, blackened on sides ; humeri yellow . . virgatus Coquillett.*

23. No dark costal stripe on wing beyond tip of first vein. . tongensis Froggatt.

— A quite conspicuous dark brown stripe along costa beyond tip

of first vein, extending to or almost to tip of wing . : 24

24. Mesonotum with a pair of presutural submedian black vittae,

separated by a pale line about as wide as one vitta in front,

fused justin front of suture, and a blackfascia extending from

each to lateral margin, but not reaching suture ; wing with

costal stripe extending to third vein from level of end of

second vein to its tip, and ceasing at, or very slightly beyond,

end of vein ; inner cross vein close to middle of discal cell . ornatissimus Froggatt.

— Mesonotum not marked as above in front of suture ; wing with

costal stripe not extending to third vein until well beyond

level of end of second ; inner cross vein beyond middle of

discal cell. , 5 d : ; : : : 25

25. Mesonotum broadly black on disc, rusty yellow on sides, and

with a similarly coloured indentation invading each side of

dark portion at suture, dark discal portion clothed with

yellowish dust ; inner cross vein at not over one-third from

apex of discal cell, and about as long as penultimate section

of fourth vein, usually faintly clouded; outer cross vein

generally slightly clouded at lower extremity in male . obscurus, sp. n.

— Mesonotum broadly brown or red on disc, with usual two

greyish pollinose vittae, which are more or less distinctly

divided and margined on sides by darker lines, and with a

creamy yellow postsutural sublateral vitta ; inner cross vein

at distinctly more than one-third from apex of discal cell,

and more than its own length from outer cross vein, not

noticeably clouded ; outer cross vein not clouded at lower

extremity . é ‘ : : : : : . tryon Froggatt.

Bezzi has used the subgeneric name Bactrocera Guérin for the species in

which there is at least one dark fascia across the disc of the wing, Dacus umbrosus

Fabricius being the type species of the group. I have drawn up the following

key for the separation of the three species included in “ Diptera Brachycera and

Athericera of the Fiji Islands,” and have added the new one described below.

It appears worth noting that I have examined specimens of D. wmbrosus in which

the fasciae on the wings are so faint that they are barely discernible, the specimens

thus falling into the same group as D. cucurbitae Coquillett. This variation 1s

an added incentive to disregard the claim of Bactrocera to generic or even sub-

generic rank.

* D. psidii and D. virgatus are here divided by the generally accepted characters ; the author's

opinion is that they are inseparable (see page 264).

TRYPETIDAE. 259

Group Bactrocera.

KEY TO THE SPECIES.

1. Wings with or without dark costal streak, and with but one

dark fascia across disc . : 2

— Wings with dark costal streak, and to dark fenciae across an 4

2. Costa without dark streak; scutellum yellow, with dark

central stripe which is widened behind. ‘ Srauenfeldi Schiner.

— Costa with conspicuous dark brown costal streak coanected

with a similarly coloured fascia over cross veins ; scutellum

yellow, without dark central stripe : 3

3. Costal streak narrow, not extending to third vein eso at

extreme apex ; middle and hind femora marked with brown

at tips, hind tibiae largely blackish brown : albistrigatus de Meijere.

— Costal streak broader, extending distinctly over third vein

throughout its length ; legs honey-yellow, tips of hind tibiae,

and last four segments of all tarsi blackened. : distinctus, sp. n.

4, The two discal fascias on wing broad, especially that enclosing

cross veins, and distinctly separated on posterior margin of

wing ; scutellum entirely yellow . : umbrosus Fabricius.

— The two discal fasciae on wing narrower, and ponfuent before

reaching posterior margin of wing, outer cross vein not en-

closed in dark fascia ; scutellum with black discal spot . longicornis Guérin.

1. Dacus distinctus, sp. n. (Text-fig. 1).

3g. Head brownish yellow, face paler, frons dull, the two black spots in

antennal foveae very small; frons with usual two anterior pairs of incurved

bristles; a dark spot below each eye. Thorax black, with following parts

yellow: humeri; a spot on posterior notopleural angle; a sublateral vitta

behind suture ; scutellum except its extreme base; posterior portion of meso-

pleura ; a spot on upper margin of sternopleura, and a double spot on hypopleura ;

mesonotum with two broad yellowish-grey pollinose median vittae, narrowly

separated by a dark line, and a similar sublateral vitta enclosing postsutural

yellow vitta. Prescutellar and supra-alar bristles present, pteropleural bristle

outstanding. Abdomen testaceous yellow, with black fascia over basal and

anterior portion of second tergite whence emanate three black vittae, one in

centre and one on each side, extending to or close to apex ; sternites fuscous ;

third tergite fringed on lateral portions of distal margin. Legs normal, testaceous

yellow, hind tibiae slightly darkened at tip, distal portion of all tarsi from a

little before end of first segment fuscous. Sensory area on hind tibia present

260 INSECTS OF SAMOA.

but inconspicuous. we as in Text-fig. 1 ; inner cross vein more oblique and

closer to eae one than usual.

Length, 6-5 mm.

Upolu: holotype, 20.vii.1925 (Buxton

& Hopkins).

e The wing markings, closely approxi-

Text-ric. 1.—Dacus distinctus, sp. n. mated cross veins, narrow frons, and very

Wine: small black facial spots should readily dis-

tinguish this species from any of its allies.

2. Dacus xanthodes Broun.

This and all the following species of the genus included in the present paper

were placed by Bezzi, in his work on the Diptera of Fiji, in Chaetodacus Bezzi,

which was given generic rank. The separation from Dacus in the strict sense

was based upon the fact that in Chaetodacus the mesonotum bears a supra-alar

bristle and a pair of prescutellar bristles, while in Dacus sens. str. these bristles

are lacking. If we accept the presence or absence of these bristles as criteria for

the recognition of genera, then we must perforce acknowledge as equivalent groups

certain others in which either of these bristles, or others of equal importance,

e.g. the pteropleural, humeral, or basal scutellar bristles, are either present

or lacking. In species such as those now under consideration, which have the

surface of the thorax quite coarsely pitted or punctate, the bristles are rather

prone to vary in degree of development and are consequently of less significance

as indices to relationships, so that I feel not even subgeneric rank should be

accorded the various segregates, because of the existence of many intergrading

forms.

In making this generalization I do not include a consideration of the African

and Asiatic forms, because, from what I have seen of at least the species of the

first-mentioned region, it appears to me entirely probable that there may be

reasons for the separation of certain segregates from Dacus (sens. Bezzi), even as

genera. In the fused abdominal tergites of some African species one finds an

apparent specialization, and, although Bezzi noted this character in some of his

descriptions, he evidently did not attach to it the importance that it actually

possesses, since he allowed the species to remain in Dacus sens. str. because of

their similarity in thoracic chaetotaxy to the species that he wrongly cited as the

genotype, namely, D. oleae Rossi.

TRYPETIDAE. 261

The subgenus Tetradacus Miyake, erected for the reception of a Japanese

species on the basis of the duplicated supra-alar bristles, is a good group, distinguish-

able by the lack of the peculiar, more densely hairy, oval area on the postero-

dorsal surface of the hind tibia of the male (which is invariably marked off on its

upper edge by a slight carina or elevated line), as well as by a few other features.

It appears to me rather noteworthy that, when Bezzi (op. cit., p. 105)

—tedescribed Dacus xanthodes Broun, he failed to notice the presence of a well-

developed humeral bristle, although he mentioned all the other thoracic bristles.

This character, which I have seen in no other species of the genus, coupled with

the peculiar scutellum, might, had he observed it, have impressed Bezzi as having

subgeneric significance, but I accept both as merely specific characters of more

than usual dependability.

Savaii: Safune, 5, 12.v.1924 (Bryan). Tutuila: Amauli, 9.vi.1923 (Swezey

& Wilder). Upolu: Apia, 1.1925, “ jumping maggot from pawpaw ”; No. 731,

“reared from human faeces”; No. 696, xi1.1924, “ex. pawpaw (Carica)

(Buxton & Hopkins). Nineteen specimens.

The record of the rearing of No. 731 is particularly remarkable.

3. Dacus aenigmaticus, sp. n.

Q. Head ? (missing in case of type). Thorax shining brownish yellow, with

following yellow marks: humeri; a narrow sublateral vitta on each side on

mesonotum, behind suture, and a large mark on posterior portion of mesopleura ;

hypopleural spot duplicated ; scutellum not paler than mesonotum, and slightly

darker on sides than in centre; centre of mesonotum with two narrow pale

vittae, from a little in front of suture to about midway between latter and hind

margin (these stripes either yellow or yellowish pollinose, but impossible to deter-

mine definitely since mesonotum is translucent, and the stripes are visible only

when surface is seen from almost the level of its upper disc) ; bristles fuscous.

Scutellum a little longer than usual, with sides slightly emarginate, and apex

narrower than base and transverse between the two bristles; surface finely

piliferous punctate. Abdomen coloured like thorax; complex basal segment

without distinct black markings; next three segments with a narrow black central

vitta, widening slightly to hind margin of fourth; same three segments with

lateral margins broadly black, fourth (visible) segment with mark tapering

posteriorly ; sheath of ovipositor conical, yellow at base, merging into black

262 INSECTS OF SAMOA.

towards tip. Legs honey-yellow, hind tibiae dark brown, tips of tarsi slightly

infuscated. Wangs yellowish hyaline, with narrow brown costal streak, very

pale at its commencement at tip of subcostal vein, becoming darker at tip of

R,, continuing round costa to well beyond middle of first posterior cell and

sometimes as a faint line to fourth vein ; anal streak very faint, not extending

into lobe; inner cross vein slightly oblique, at about two-fifths from apex of

discal cell. Halteres yellow.

Length (approximate), 5 mm.

Upolu: Malololelei, 2,000 feet, holotype, 25.vi.1924 (Buxton & Hopkins).

As in the two preceding species, the mesonotum bears a prescutellar and

two postalar and notopleural bristles, but there is no trace of the supra-alar

bristle, and the humeral is lacking as usual. It must be noted that when Bezzi

refers to three supra-alars, placing the emphasis upon the presence or absence of

the anterior supra-alar, he includes as supra-alars the two postalars, though the

anterior supra-alar is the only one of the three entitled to the designation.

3a. Dacus luteola, sp. n.

36. Head honey-yellow, frons dull except upper orbits and narrowly along each

eye; two anterior pairs of incurved bristles yellow, and very difficult to dis-

tinguish ; third antennal segment and arista dark brown; face without black

spots. Thorax and abdomen honey-yellow, of the peculiar translucency some-

times seen in specimens of this genus, which when present renders it difficult

definitely to distinguish yellow markings; humeri apparently paler than

mesonotum. Bristles fuscous. Legs normal, coloured like abdomen, tips of

tarsi slighly darker. Wangs with costal streak a little wider than in D. aenig-

maticus, but much paler and extending to fourth vein round wing tip, where it

is darker and of uniform width as far as the vein ; anal streak reaching margin

of wing, but merely yellowish brown ; both cross veins narrowly and distinctly

suffused with brown, inner one oblique and situate about two-fifths from apex

of discal cell.

Length, 6 mm.

Society Islands: Bora Bora, holotype, 21.vi.1925 (L. E. Cheesman).

I believe I am justified in including this species in the present paper, although

it has not as yet been found in Samoa. Provided that the food of the larva

occurs in Samoa, it is quite probable that the discovery of the insect there is

merely a matter of time.

TRY PETIDAE. 263

3B. Dacus facialis, Coquillett.

A small species much resembling D. aenigmaticus and D. luteola in general

appearance. The face, however, is yellow and unspotted ; the pleura are largely

yellow, the humeri entirely so, and the scutellum is yellow except at the extreme

base; the abdomen has irregular central and lateral black markings on the

tergites. Wangs much as in D. aenigmaticus, but the costal streak ends closer

to the third vein.

Tonga Islands: Nukualofa, 15.11.1925 (Hopkins).

The specimen referred to above was compared with the type material in the

United States National Museum, and, though it differs from the type in certain

features, as do some of the specimens recorded by Bezzi (op. cit., p. 104) from the

same islands, the determination is undoubtedly correct.

4. Dacus tongensis Froggatt.

A teneral specimen, which I assign to this species, is included in the present

collection. In most characters it resembles D. aenigmaticus, but the mesonotum

bears a distinct supra-alar bristle, and there is no noticeable brown costal stripe

beyond the tip of the first vein.

Upolu: Vailima, 8.vi.1924 (Buxton & Hopkins).

4a. Dacus tryoni Froggatt.

Despite the opinion of Bezzi that D. tryoni Froggatt is merely a variety of

D. ferrugineus Fabricius, I incline to consider it a good species. I have before

me Australian examples of D. tryoni and Oriental specimens of several named

varieties of D. ferrugineus, and find differences which are apparently of specific

value. No specimens of either species are amongst the Samoan material.

5. Dacus psidiu Froggatt.

A readily distinguishable species owing to the deep shining black mesonotum,

with its broad, central, greyish pollinose vitta, and similar though less distinct

and narrower postsutural vitta on each side, the blackened upper margin of the

humeri, and the broad black central stripe on the scutellum.

Savai: 1,000 feet, one specimen, 21.x1.1925 (Buxton & Hopkins). Also

one 2 from Samoa, possibly Apia, in the United States National Museum (Doane),

and one Q, Society Islands: Papeete, vi.1928 (Tonnoiz).

264 INSECTS OF SAMOA.

5a. Dacus virgatus Coquillett.

After carefully examining the type of this supposed species in the United

States National Museum, I am convinced of its specific identity with D. psidii

Froggatt. I have included D. virgatus in my key, separating it on the only

character that is distinguishable, but the type is teneral and the pin has drawn

the contents of the thorax away from the surface so that it is partially translucent ;

thus it is difficult to determine the actual colour of certain parts, especially the

scutellum and humeral calli. I believe that the former would under normal

conditions be entirely black in the centre, and that the humeral calli show a

trace of the black upper margin, which is characteristic of D. psidiz and of no

other species known to me.

I put forward this synonymy as practically certain on the basis of my

examination of the type, and my identification of the material referred to above

under D. psidii.

6. Dacus obscurus, sp. n.

$2. Broader and duller in colour than D. ferrugineus. General colour

rusty yellow, with disc of mesonotum broadly black, as described in the key

given above. Face with the black spots rather large. Plewra sometimes

rusty yellow, with only lower part of sternopleura black ; black colour some-

times more extensive ; scutellum rusty yellow; thoracic and cephalic bristles

fuscous. Abdomen with ground colour rusty yellow, dorsum with a linear black

median stripe, and broader lateral vittae of same colour. Legs yellow, hind

tibiae and all tarsi, except basal two-thirds of basal segment, infuscated. Wangs

with distinct anal and costal brown streaks, latter but slightly widened at distal

extremity as in D. ferrugineus, and extending to about midway between tips of

third and fourth veins; inner cross vein usually faintly infuscated, outer one

shghtly clouded at lower extremity in 3.

Length, 7-8 mm.

Upolu: Apia, holotype g, 17.11.1923; Malololelei, allotype, and three

paratypes, 9.vii.1922 (Armstrong) ; Samoa, no other data, but probably Apia,

two paratypes (Doane, U.S. National Museum).

TRYPETIDAE. 265

6A. Dacus bezzi Miyake.

Bull. Imp. Cent. Agr. Exper. Sta., Japan, vol. 2, No. 2, p. 146, 1919.

Dacus scuiellatus Hendel, Suppl. Ent., Berlin, No. 1, p. 20, 1912.

I have examined some of Miyake’s material in the United States National

Museum, and consider it highly probable that his species is the same as D.

scutellatus Hendel, the type of which was obtained in Formosa. Bezzi (op. cit.,

p- 103) mentions the latter in his notes under D. quadrisetosus Bezzi, but does

not include it in his key (op. cit., pp. 100-102). I have seen a male of D. scutellatus

Hendel from Hong Kong, which justifies me in making the above suggestion as

to synonymy.

The species, although not yet taken south of Formosa, may still be found

in some of the Pacific Islands. The food-plant is not recorded.

CERATITINAE.

Hemilea Loew.

This is the genus recorded by Bezzi (op. cit., pp. 4, 107) as Ocneros, Costa,

but Costa’s genus is synonymous with Palloptera Fallén, having the same geno-

type, Musca pulchella Rossi, and consequently the name cannot be used in this

family ; Loew’s generic designation subsequently proposed has therefore a valid

claim to recognition.

There are two palaearctic species of the genus, both of which have the black

colour of the wing extending but little over the fourth vein in its distal half,

whereas in the Samoan species the black colour extends to, or almost to, the fifth

vein throughout its entire extent.

7. Hemilea punctilabris (Bezzi).

The original description of this species (Bezzi, op. cit., p. 107) is accompanied

by an excellent figure of the wing by Terzi.

Upolu: Malololelei, 2,000 feet, one (headless) 9, 19.viii.1925. This is the

first recorded female of the species.

266 INSECTS: OF SAMOA.

TRYPETINAE.

Spathulina Rondani.

8. Spathulina acroleuca Schiner.

This species occurs in Egypt, South Africa, and throughout the Indo-

Australian region, but the specimens show a certain amount of variation. A

good description, with a figure of the wing, is given in Hendel’s recent mono-

graph of the palaearctic species.*

Hendel deals with the variations of this species, but in none of the Samoan

examples does the outer hyaline mark in the first posterior cell of the wing

appear as shown in his figure, extending as it does there into the first posterior

cell. In one Samoan example the outer of the three hyaline spots in the sub-

costal cell is lacking, and in two other specimens the first, or inner, of the two

hyaline marks in the second posterior cell is in two sections. It would appear

hardly worth while to attach names to these forms, as has been done by Bezzi.

It may be worth noting that all my specimens of the species from New South

Wales have the hyaline marks larger than in the Samoan examples, the two marks

in the second posterior cell extending from margin to fourth vein.

Upolu: Malololelei, 1, 1, iv, vi (Buxton & Hopkins), vi. (Armstrong),

vu. (Wilder) ; Afiamalu, 7.xi.1925 (Wilder). Savaii: Safune, 22.v.1924 (Bryan).

Tutuila : Leone Road, 9.viil.1923 (Swezey & Wilder), and Pago Pago, 9.xi.1923.

I have also before me one specimen from the Tonga Islands: Vavau, Neiafu,

5.11.1925 (Hopkins).

* Lindner, Die Fliegen der palaearktischen Region, 49, pp. 116, 117, Taf. VII, fig. 3, 1927.

PRINTED IN GREAT BRITAIN BY WILLIAM CLOWES AND SONS, LIMITED, LONDON AND BECCLES.

INSECTS OF SAMOA

AND OTHER SAMOAN TERRESTRIAL

ARTHROPODA

LIST OF PARTS AND SYSTEM OF PUBLICATION :—

Part I. Orthoptera and Nes

1 Hemiptera.

,, III. Lepidoptera.

ca) tN Coleoptera.

Me ee OES Hymenoptera.

: » MI. Diptera.

,, VII. Other Orders of Insects,

» VIII. Terresirial Arthropoda other than Insects.

Le 9 De ‘Summary and Index. !

The work is published at intervals i in the form of numbered fascicles.

ane Kichough individual fascicles may contain contributions by more than one

author, each fascicle is so arranged as to form an integral portion of one or

aie other of the Parts specified above. ae

ae of Fascicles eae to 28th November, 1931- —

: Insects of Samoa and: other eean Terrestrial Arthropoda. Maps | and Date Issued.

_ 2 (imenvelope). 1927, 4to. 6d. : ! Bae 26th February, 1927.

Parr I. ORTHOPTERA AND -DERMAPTERA. : one Sih Ma ake

_ Fase. 1. Dermaptera. By Dr. Alfredo Borelli. Pp. 1-8. 1928, 4to. Is. 28th July, 1928.

My Dy) Fasc. 2. Orthoptera. Eye L. Chopard. 51 Hes heures: Pp. 9-58. 1929, 4to. 5s. 26th January, 1929.

BY Aine ; a i { 3

o Pari II. Pierce J | | |

ot i ae i Fulgoroidea. By F. Muir, Ys) Pan Peylide (Cherie), By |

rawford. | 4 text-figures. occide, Aphidide and Aleyrodide.

By F, Laing, MA., BSc. 3 text-figures. Pp. 1-45. 1927, 4to, 2s. 6d. 25th June, 1927.

* ke 2. Cerco idee. By V. Lallemand, MD.. 10 Peer tee! Cicadide. By

; Meer se 22 text-figures. Aquatic and Semi-aquatic Heteroptera. .~) | |)

oe Teiso sae 6 text-figures. Pp. 47-80. 1928, 4to. 2s. 6d. 23rd June, 1928.

Lae Pe 41 | ea _ By W. E. China, B.A. Gere 28 text-figures

930, 410. 5s, | Oe ace Aes aa dente ul 19308

iy Part ne ‘Lepiporrana. |

qe race A Baittertiesid Sanba andl hbpurhe lender ENS

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: Fas sc. 2. Se By Edward Meyrick B.A., F.R.S. Pp. 65-116. 28th May, 1927.

1927, 4to

ae 3. Geometnd By Loui B. Prout, FES. eee k d 1 pt

Petrie.” 1928, fio: Bb o TO aOR E ON QAiB Matahs (928.

List of F ascicles issued to 28th November, 1931 (ontnal)

Part IV. CoLEoPTERA. eA nt

Fase. 1. Carabide. By H. E. Agdeewes, He rg face Die ie NG cp piled

eoAnimencanne ie ae ‘Staphylinide. By M. Cameron, MB... Qitextel jin:

ene Hydrophilide. ayer le neers Ceeone and: sai

Lamel licornia. By G. J. rele 13 text-pures, 1927, 4to. 3s.

Fasc. 2, Sot Ha Bostrychoidea, eos a ae Beko G.

Blair, B 14 text-figures. Elateride. H. van Zwaluwenberg. 10

Por haute ec uelneide cece maids By a Fleutiaux. Cerambycide, By

hr. Aurivilli i tes ot hides By R. Kleine. 4 text-figures.

Anthribide. Kart ordan, Ph.D. 11 text-figures. Proterhinidee. (By ctinns

R. C. L. Per Ge DS, RS. be BF-174. 1928, 4to. 5s.

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By S. Maulik, M.A. 18 text-figures. Pp.175-215. 1929, 4to. 2s.6d.

Fase. 4. Platypodidae and Scolytidae. By C. F. Cc. ‘Beeson, DSc. we text-

~~ figures. Pp. 217-248. 1929, 4to. 2s. 6d. ey

Fasc.5. Curculionidae. By Sir Guy Marshall, CMG, DS, FR

figures. Pp. 249-346. 1931, 4to. pe ie

Part V, HyMeENopTERA.. we Nappe climes SE DE OE .

_ Fase. ie Apoidea, Sphecoidea, ar Veqtides By R 1 Relkides DSc ee

., and. a Evelyn Cheesman, BES. iiZ.9: 12 teach res. Larride.

By Francis. pat aie. 12 text-figures. Formicide.. ee

9 text-figures.. 158. 1928, a 5s. ie

Part VI. ee A al ee are ey ees

Fasc. 1. Streblide a Ngeeaeide ‘By |e Pie 7 eee Hippo. Oe

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figures. Larve of esac hd _By P. A, Buxton, M.A. 2 text-figures

Dolichopodidee, SoD. 8 text-figures, BR Nel By

P. A. Bux ” MA. ‘9: cereigure, Mascige. - Malloch.

Pp. 109-175. "1929, Ato,

Fasc. 4. Em ididae and Pipuneitidac® oo ape E. Collin. 4 ae

Syrphidae. By Frank M. Hull. 2 text-figures, Clusiidae (Heteroncundas)

ad Sapromyzidac. ‘By/J. R. Malloch. ie ies) Pp. W213, We

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Fasc. 7. Trypetidae. By]. R. Malloch. I text-figure. Pp. 253-266. 153, Ato. ee

Part VII. OTHER Orpers OF INsEcTs..

Nee 1. Isoptera : Family Termitide B Gerald F. Hill, “14 ae and)

plate. ‘Odonata. By Lt.-Col. C. Fraser, IM oh FES. iD text-figures.

Pe 1-44. 1927, 4to. ee iy

Fasc. 2. Plectoptera. R. J. Tillyara, ScD. ‘Cantab.), me RS, na 1) Aye x

linet Richard S. Bagnall, F R

Lestage. poate shonay tera. By P. A. Buxton, \ Thysanoptera. ne

eke E'S. Gtext-fgures. Pp. B16" TRO. ot

fen 7 Mallph By Naterston DSc. 2, texe-Aeures.. ee |

Buxton, MA ‘vichoptera. By Meme Le Mosely: 1 figure.

Nice By P, Eshen-Petersen, { text-Aigure an lates. asec

By George H. Gee oee 32 text-figures. “Pp. Wie 1928, Ato. 2s. 64.

Part VIII. Trrrestriat ARTHROPODA OTHER THAN INSECTS. ust -

Fasc. 1. Isopoda Terrestria. By Harold G. Jackson, DSc. of plates. ome

pionoidea. By uxton, M.A. Pseudo-scorpiones. By A. Kastner. _ 1

text-figures. Acarina. By Stanley Hirst. 2 fetmanes Pp. i nee isz7,

4to. 2s. 6d. a

Fasc. 2. Myriopoden (Myriopoda By Ne 4t hein ‘Ar. ées ss ae

(Araneida), By Da lacion ae Pret: figure, Po. 2i-78 4 i vee 2nd tie 1 929.

Part i SUMMARY AND INDEX.

Fasc. 1. Description of the Fe yronmienk: By P. A Buxton, MRCS. 2

meseaeiee and 6 plates. Pp. 1-31. 1930, Ato. 2s. oS