the dipterous genus zygothrica of wiedemann.

THE DIPTEROUS GENUS ZYGOTHRICA OF WIEDEMANN.

A. H. Sturtevant, Of Columbia University,

New

York City.

In the year 1830

Wiedemann

^{^}describeda Brazilianfly underthe

name

ofAchiasdispar,thegenus Achiasbeing placed ⁱⁿthe family Diopsidae. This specieswasso placedonaccount ofitsbroad head with conically produced eyes.

Wiedemann

stated that this char- acteris

much

more

marked

in themale than in the female. Inthe

same

year he publisheda revisionofthe speciesof thegenusAchias., inwhichhe

made

A. dlspar the onlyspeciesof a

new

genus, called ZygothHca.^

Two

years later

Gray

^{^} published a figureof the species. Itwas againfiguredbyMacquart.* Macquart^ discussed the species, and placed it doubtfully in his family Lauxaniidae. It does not seem certain from his account that he had seen a specimen.

The

figure isperhapsacopyofthatof Gray,andthe description

may

havebeen takenfromthatof

Wiedemann.

The

next referenceto Zygothrica was by Loew.*'

He

hadseen a specimenthat

was

perhapsZ. dispar,and onthebasisof thatspeci-

men

referred the genus doubtfully to the Drosophilidae. Bigot^{^} tabled the genus

among

the Diopsidae, apparently without having seenit. Osten Sacken^{^}statedthathe

had

seenaspecimenthat

made

on

him

the impression ofaDrosophilid.

Hendel" mentioned ^thegenus in connection with Plagiocephalus

Wiedemann. The

^latteris an Ortalidgenusthat wasalsobasedon aBrazilianspeciesfirstdescribedby

Wiedemann

asanAchias.

Hen-

del

had

apparently not seenZygothrica^ but suspected thatitmight possibly be an Ortalid.

Two

^{years later,} however," he

had

seen

»Aussereurop.Zweifl., vol. 2,p. 556.

"Achias Dipt., Genus10,p. 3.

sAnimal Kingdom,vol.2, p.774, 18.32.

*Dipt. Exot.,vol. 2, pt. 3, pi.34,fig.2, 1843.

5Idem.,p.409.

«Mon. N. Amer.Dipt., vol.3, p.23,1873.

'Annales,p.91,1880.

8Dipt.MalayArch.,p.90, 1881.

»Gen.Insect., p. 113,fasc. 52,1911.

lODeutsch. Ent.Zeit.,p. 633,1913.

ProceedingsU.S.National Museum,Vol.58-No.2330.

155

156 PROCEEDINGS OF THE NATIONAL MUSEUM.

^vol.58.

specimensfrom Peru that he identified as Z. dispar.

He

referred the genus to the Drosophilidae, and redescribed and figured it.

Later^{^} he added a few notes, attributed Wiedemann's figure to Meigen.

De

Meijere^{^}comparedthegenus withhis

new

genus Sphyrnoceps^

which he concluded is distinctbecause neither sex has as broad a head as that of the male of

ZygothHca

dispar.

Both

Zygothrica and Sphyrnocepsare referredto laterbyde Meijere^, and Hendel's figureisreproduced.*

Ihaverecentlyexaminedalargeseriesof specimensinthe United States National

Museum

that are evidentlyZygothricadisparWiede- mann,towhichspeciestheyweretentativelyreferredbythelateMr.

F. Knab. These leave no doubt that the reference to the Droso- philinaeiscorrect. Since theycomefrom

Panama,

theyaddanother genus tothe ^"North American^" list.

Both

sexes agree in having a verylongproboscis,thathas not been describedbyearlier authors.

Itissometimesretractedandnoteasilyobserved,whichprobablyac- counts forthis oversight.

The

females agree wellwiththedescrip- tion of Drosophilura caudata Hendel.^ This genus (and species)

was

based onfemale specimens fromBolivia,whileHendel

had

seen onlymales from Peru thathe referred to Zygothrica dispar.

The

most strikingcharacter described forDrosophilura is the long pro- boscis, whichHendel

had

overlooked in his males. Anotherdiffer- ence is that Zygothrica is stated to have two orbital bristles,

Drosphilura three. Just this sexual difference occurs inthe series of specimens that Ihaveexamined.

Thereisanotherspeciesinthe samelotthat Ihavehere described asa

new

species ofZygothHca. In this form both sexes have the head shaped asitisinthe female of Z.dispar. Icanfind noother significant differencebetweenthetwo^forms,andtherefore have put them inthe same genus. This makesit probable that Sphyrnoceps de Meijereisa

synonym

ofZygothHca;but amore detailed descrip- tion, especially of the structure of the proboscis, will be necessary beforethisconclusioncan beadoptedas certain.

We may

tabulateanddefinethegenusasfollows

:

Genus

ZYGOTHRICA

Wiedemann.

ZygothricaWiedemann, 1830,AchiasDipt., Genus16, p.3,

DrosophiluraHendel,1913, Ent. Mitth.,vol.2,p.387.

ISphyrnoceps de Meijere,1915,Tijtls.v. Ent., vol. 58,suppl., p. 58.

Aristaplumose;two or threeorbitals; vibrissae present; postver- ticalslarge;faceprominent;carina large;headbroaderthanthorax

;

»Abhandl.k.k.zool.-bot. Ges.,vol.8,p.219,1914.

"Tijds.V.Ent,vol.58, suppl.,p.59, 1915.

«Diptera, inBronn's Klassenund Ordnungen5,vol.3,p.45, 1916.

*Idem,pi.2, fig.13.

BEnt. Mitth.,vol.2, p.387, 1913.

No.2330.

DIPTEROUS GENU8 ZYG0THBICA—8TURTEVANT. 157

proboscis longerthanheadishigh; noprescutellars; preapicalsevi- dent on second and third tibiae; discal and second basal cells con- fluent_;costalvein reachestoapexof fourthvein.

Wiugsclear; eyes laterallyproducedto a sliarp liorizoutal edge inthe male;

mesonotum brown Z. dispar.

Wings ornamented; eyes of male not produced; mesonotum shining black Z. aldricMi.

Wingsclear;eyes notproducedinthemale; mesonotum brownZ. {?) brunnea.

ZYGOTHRICA DISPARWiedemann.

DrosopMliiracatidataHendel, Ent. Mitth., vol. 2,3913,p. 387.

Both

sexes have been fullydescribed by Hendel.

The

preapicals are evidentonthe second and thirdtibiae; other than thishis cle- scrij)tionsfitthematerialIhaveseen.

The

species is,however,vari- able in color.

The

descriptions of this character given by Wiede-

mann

and by Hendelinhistwo

papers can all be matched in theseries,but thedarker types are mostfrequent.

Specimens examined: Trini-

dad

River (over 150 specimens, 11 of them bred from "white toadstool"),Alajuelo (4 speci- mens),

Panama

(A.Busck).

Recorded from Peru (Hen- del), Bolivia (Hendel), and Brazil (Wiedemann).

ZYGOTHRICA ALDRICIIII,newspecies.

Male.

—

^Arista withabout six branches aboveand twobelow.

Antennaeyellowishbrown. Front about halfwidth ofhead above, narrowerbelow. Threeorbitalbristles. Frontshining yellowbelow

;

orbits and triangle reddish brown, frontal lines black. Postverti- cals large. Eyes nearly bare. Carina large. Face protuberant, yellow.

One

large oral bristle. Proboscis longer than height of head;itandpalpiyellow. Cheeksyellow.

Acrostichal hairs in six rows.

Mesonotum and

scutellum shining black. Pleurae andlegspaleyellow.

Abdomen

shiningblack.

Wings

withthreeblackspots

—

^abasal one extendingonthe costal marginto justbeyondtheapexof thefirstvein,and reachingtothe fifth vein,thus including theanterior crossvein; oneonthe anterior marginextending froma point above theposterior crossvein tothe apex ofthe fourthvein; one around the posterior crossvein. Costa witha breakatthehumeralcrossveinandanotheronejustbefore the

Fig. 1.—ZYGOTHRICA DisrEE Wiedemann. Up- per, HEAD OP MALE FROM ABOVE; LOWER, HEADOFMALE FROMINFRONTANDA LITTLE BELOW.

158 PROCEEDINGS OF THE NATIONAL MUSEUM.

^vol.58.

apex of the first vein. Costal index about 1.9; fourth vein index about1.3;5xindexabout1;4c index about0.8. Firstposteriorcell slightly narrowedatitsapex.

Length,2.5

mm.

Type.—

Male, Cat. No. 22725, U.S.N.M., from Trinidad River,

Panama

(A.Busck).

Female.

—

^Proboscis, lower part ofpleurae, and second and third coxae shining blackishbrown. Otherwiseasabove.

Allotype.

— ^Same

locality as type.

Paratypes.

—

^Thirty-one specimens taken with the type and allo- type. Threeofthesewerebredfrom"whitetoadstool." Thisseries

was

takenwiththe largeseriesof

Z

dispar referredtoabove.

Some

of the paratypes are distinctly palerin color than thetype, appar- ently having been pinned

when

younger. In these specimens the

wing

spotsare smallerorevenabsent,andthemesonotum,scutellum, and

abdomen

arebrownishoryellowish.

The

speciesis

named

for Prof.J.

M.

Aldrich, to

whom

I

am

in- debted forseveralof thereferences tothegenusandfor otherfavors.

(SPHYRNOCEPS) ZYGOTHRICA (?) BRUNNEA deMeijere.

Sphyrnoceps hrunnea deMeijere,Tijds. v.Ent.,vol. 58,1915,suppl.,p.58.

Eyes roundedinbothsexes. Thorax, dark

brown

above, paleyel- lowbelow.

Wings

clear.

Describedfromtheisland ofSimalu,offSumatra.

NOTE.

Since the foregoing

was

written I have examined a series of specimens takenonadecaying agariconrotten log, at

Emperor

Val- ley,Portof Spain, Trinidad,

West

Indies; January, 1913, by Prof.

Roland Thaxter. This series, which is preserved in alcohol, in- cludesnumerousspecimens ofZygothricadisparand ofZ. aldrichii.

An

examinationof thespecimens of Z. disparand reexamination of some of the United States National

Museum

material shows that the males of this speciesare quitevariable in the structure of the head.

A

^fewof

them

have roundedeyesand three orbital bristles, exactly as in the females. There is a continuous series connecting theseformswith those thathavevery long pointed eyesand nosecond orbital bristle. This observationserves to strengthen the view that Z.aldrichiiandthegenusSphyrnocepsshouldbe placedinthesame genusasZ. dispar.