J. Bequaert.
New Nemestrinidæ (Diptera) from Rhodesia and New Guinea.
Psyche 32:4-22, 1925.

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4 Psyche [February
NEW NEMESTRINIDB (DIPTERA) FROM RHODESIA AND NEW GUINEA
BY J. BEQUAERT.
Department of Tropical Medicine, Harvard University Medical School.
The curious and apparently archaic family Nemestrinidse is rather abundantly represented in South Africa, but very few species are known north of the Orange and Limpopo Rivers. It is, therefore, of much interest to record three new forms, of the genera Prosceca and Stenobasipteron, which have been re- cently discovered in Southern Rhodesia. I wish to thank Dr. G. Arnold, Curator of the Rhodesia Museum, Bulawayo, for the opportunity of studying these insects. On this occasion I shall also describe a new species of A yrtnrimyia, from New Guinea, entrust,ed to me some time ago by the Paris MuL aeum.
Prosoeca rhodcsiensis sp. nov.
Type female from Matopos, Southern Rhodesia, April 17, 1923 (R. Stevenson Coll.); allotype male from Mt. Bambata, Matopos, Southern Rhodesia, March 23, 1924 (without collector.) Both in the collection of the Rhodesia Museum, Bulawayo. A robust, black species, covered with dull grey tomentum; vertex and dorsum of thorax with short black hair; pilosity otherwise greyish white, very long and dense on the under side; a dorsal row of brownish black, dull spots on the middle of ab- domen; legs dark clove brown. Wings of normal shape in the male, with all longitudinal veins turned up at apex; brownish along costa and gradually fading into the hyaline hind margin. Female: Inteffument black, faintly clove brown at extreme lower apex of face. Antenna, palpi, and proboscis black; the proboscis faintly clove brown toward' the base. Legs very dark clove brown, the tarsi and claws almost black. Body short pilose above, densely hairy on the ventral side. Vertex with erect, black hairs as far as the anterior ocellus; the remainder of the head with white pile, which is extremely short



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19351 New Nemestrinidos from Khffdesia and New Guinea 5 on the front, longer on the face and posterior orbits, and very long and dense on the cheeks, Dmsum of thorax with moder- ately long and rather spame, erect, black pile; scutellum with similar, but somewhat longer, black hair, except behind its posterior margin; where the pilosity ie greyish white; sides and ventral face of thorax densely covered with long, soft, greyish white hairs, which extend as a distinct white stripe above the base of the wing. Abdomen dorsaUy with sparse and short, erect, black pile; at the bask and along the hind margins of the segments there is a mixture of greyish white hairs; ventrally the piloisity is longer, denser, greyish white, and generally appresse-d, Cox= and femora with long,.greyish white hairs; the pilosity of the tibiae and tarsi extremely short, black; the longer 5etse at the tip of the tibise also black. Except where the pilmity is very long and dense, the integument is covered with a dull, isfey grey bloom; on this, one may see, in the proper light, two wide, longitudinal stripes of blackish pruinescence in the anterior half of the thoracic dorsum, on each side of, and close to, the middle line. Brownish black pruinescence also form's a row of median, rounded, dull spo& on the second, third, and fourth abdominal tergites; each spot "being located close to the anterior margin. In the female I have seen, these spots are quite well marked. Head large, flattened, much broader thm the thorax; semi-eIUptical in profile; kidney-shaped and nearly one and one-half times as wide as high when seen in front. Front rather narrow, widest at the insertion of the antennae, where if mekes about half the width of the eye ; the inner orbits converge dis- tinctly toward the ariterior ocellus, where the front is only half svs wide as at the antenme. Vertex nearly parallel-sided. Ocellar protuberance elongate and low, but slightly separated from "the inner orbits, with a transverse, saddle-shaped depression in the middle; oceE placed in an isosceles triangle, the posteriw ocelli being only about half as far from each other as from the an- tenor ocellua. Eyes bare. Antenna short, email, placed on the sides of the face, close to the inner orbits; basal segment subcylin- dried, slightly longer than wide, broadly truncate and m e - what emarginftte at apex; second segment nearly as long as wide, about two-thirds the length of the first, aqaardy truncate



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6 Psyche [ ~ e bruar
at apex, with rounded edges; third segment flattened, pear- shaped, but little shorter than the first and second segments together, twice as long as wide, broadest in its basal half and thence gradually narrowed to the truncate and slightly sinuate apex. Style longer than the whole antenna, very sharply three- jointed; the two basal divisions thick, of about equal length, together about two-thirds the length of the third antenna1 seg- ment. Front slightly convex between ocelli and antennae. Face moderately swollen as a whole, gradually slanting from between the antennae to the oral margin, without grooves. The lower part of the head distinctly excavated between the cheeks. Proboscis of medium length, reaching about to the hind margin of the scutellum if supposed folded beneath the thorax; rather thick, especially in its basal half; directed downward, with a slight posterior slant. Palpi short and thick, three-jointed; the second segment much the longest; the apical segment bluntly truncate. Body quite broad and heavy. Thorax distinctly broader than thick; dorsum slightly wider than long; transverse suture quite deep on the sides over one-third of the width of the dorsum, continued as a shallow, oblique depression to near the scutellum. Scutellum large, semi-elliptical, cushion-shaped, its posterior margin separated from the disk by an impressed line. Abdomen broad and flat; the four basal segments together shorter than wide; the succeeding apical segments much nar- rower, decreasing in width, partly retractile within one another to form a telescope-shaped ovipositor; the last segment ends in two short, slender, straight, bluntly pointed lamellae which are wider in their basal half (in profile). Legs stout and long; the tarsi especially thick; the hind basitarsus but little narrower than the hind tibia.
Wings rather long and narrow, much longer than the body, over three times as long as wide. Costal cell and extreme base of wing, as far as the branching of the fourth and fifth longitudi- nal veins, infuscate, with a brownish yellow tinge; then fading into greyish in the first basal and subcostal cells and also along the costa to the tip of the wing; the remainder of the wing, in- cluding the alula, nearly hyaline. Veins dark clove brown or nearly black. Epaulet and basicosta clove brown; the epaulet



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19251 New Nemestrinidce from Rhodesia and New Guinea 7 with a tuft of long, appressed, white hairs. Venation of the usual Prosceca-type; all the longitudinal veins turned upward to end before the apex of the wing; no cross-veins between the terminal branches of the fourth vein nor between the second and the
upper branch of the third; fourth posterior cell sessile. Length not including ovipositor (to apex of tergite 4)) 16.5 mm; greatest width of abdomen, 8.5 mm; length of proboscis, 8.5 mm; length of wing, 21 mm; width of wing, 6 mm. Male. Very similar to the female in every respect. The abdomen is more clove-brown than black, but this is probably due to the fact that the greyish bloo111 is not as well preserved in the specimen in hand; the dull, black spots on the middle of the abdomen are present, though not quite as distinct as in the female. The vertex is just a trifle narrower at the anterior ocellus than in the female; but the ocellar triangle is still much longer than wide behind. The wings are slightly wider and a little more infuscated than in the female; but there is no pro- minent thickening of the costa beyond the middle and the passage to the nearly hyaline hind portion of the wing is quite gradual. The venation is as in the female. Total length, 18.5 mni.; greatest width of abdomen, 9 mm.; length of proboscis, 9 mm.; length of wing, 23 mm.; width of wing, 6.7 mm.
This species is closely related to Prosceca beckeri Lichtwardt, of which it was at first tlhought to be but a variation. Owing to
the kindness of Dr. H. Brauns, I was able to examine a male of P. beckeri from Montagu Pass, George, Cape Province. It differs from the Rhodesian male in several structuril peculiarities which, however, could not be gathered from published accounts. Thus
the wing of P. beckeri is, in the male, prominently widened beyond the middle, the costa being there considerably thickened (length of wing, 21 mm.; width of wing, 6.5 mm.); the wing being shaped somewhat like that of the males of Ommatius (Asilidae) and of Stenobasipteron (Nemcstrinidse) . Such a struc- ture of the wing is not found in the male of P. rhodesiensis. In addition, P. beckeri has the wing much darker in its anterior half; the vertex is quite broad, the ocellar tubercle shorter than wide, the two posterior ocelli being somewhat farther from each



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8 Psyche [February
other than from the anterior ocellus; the style is much shorter, being about as long as the whole antenna; there are also minor differences in the color of the pilosity, the hairs of the dorsum of the thorax being to a large extent greyish white, and there are two rows of blackish spots on the abdomen, instead of one row as in P. rhodesiensis.
Stenobasipteron arnoldi sp. nov.
Type female from Mt. Bambata, Matopos, Southern Rhodesia, March 23, 1924 (without collector) ; paratype female from the same locality and date. The type in the collection of the Rhodesia Museum; the paratype in my collection. A slender black species, covered with dull, cinereous tomen- turn; head and under side of abdomen paler; antennae and legs dirty straw yellow; pilosity sparse; longer and denser on the ventral side; proboscis considerably longer than the body. Wings very long and narrow, with the usual venation for the genus, very slightly sn~oky, more infuscate in the costal cell. Female. Integument black on upper part of head and on dorsal face of thorax and abdomen.
Face pale clove-brown.
Sides of thorax blackish, with indistinct, yellowish brown blotches. Ventral face of abdomen pale dirty yellow. Antennae yellowish brown, the last division of the style black. Palpi clove-brown. Proboscis black. Legs entirely pale testaceous; claws black.
Pilosity sparse (probably but partly preserved in the two specimens seen). Vertex, front and face with very few, but long, erect, black hairs; cheeks and posterior orbits densely covered with long, greyish white pile. Dorsum of thorax and scutellum with sparse, but rather long, erect, black hairs; sides and ventral face, as also under side of scutellum, with more abundant and longer, somewhat yellowish white pilosity. Dorsally on the abdomen the hairs are mostly black, except at the extreme base; the anterior third of the second tergite has a sparse, erect, long, black pilosity; the remainder of the dorsal side bears many scattered, extremely short, slanting, rather stiff, black hairs. Ventrally the abdomen is but poorly covered; there are a few,



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19251 New Nemestrinidce from Rhodesia and New Guinea 9 short, appressed, somewhat silvery white hairs, which are more abundant toward the sides. Coxse and femora with long, yellowish white pile; that of the tibiae and tarsi extremely short, white; the under side of the tarsi with more abundant, reddish brown pile. The integument of the entire body is covered with a dull, dark ashy grey bloom; on the front and face the pruines- cence has a slight yellowish tinge, and it is much paler, nearly white on the ventral side of the abdomen; there are no spots nor stripes on thorax or abdomen.
Head moderately flattened, much broader than the thorax; semi-elliptical seen from above; triangular in profile, due to the conically projecting face; kidney-shaped and nearly twice as wide as high in the middle, when seen in front. Front rather
narrow, widest at the insertion of the antennae, where it measures about half the width of the eye; inner orbits distincttly converg- ing toward the anterior ocellus, where the front is but half as wide as at the antennae. Sides of the vertex slightly diverging behind. Ocellar protuberance short and low, about as wide as long, but slightly separated from the inner orbits; ocelli placed in an equilateral triangle; anterior ocellus over twice the size of each of the posterior ocelli, transversely elliptical, occupying more than half the width of the front. Eyes bare. Antenna (Fig. la) short, small, placed on the sides of the face, close to the Fig. 1. Stmobasipleron.
Right antenna drawn from the inner side: a, 5. a~noldi; b, S. difficile; c, 5. gracile.




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10 Psyche [February
inner orbits; basal segment cylindrical, nearly one and a half times as long as wide, squarely truncate at the apex; second segment a little over half the length of the first, about as long as wide, slightly broader at the apex which is broadly rounded off; third segment slightly flattened, short pear-shaped, but little longer than the first, and slightly over one and one-half times as long as wide, widest in its basal t,hird and thence grad- ually narrowed to the straightly truncate apex. Style about twice the length of the whole antenna, sharply three-jointed; the two basal divisions together but little shorter than the second and third antenna1 segments; the second division some- what longer than the first. Front very feebly convex between anterior ocellus and antennae. Face much swollen, projecting anteriorly as a blunt cone, without grooves. The lower portion of the head is deeply and broadly excavated in the middle between the cheeks, the eyes continuing for about one-quarter their length below the oral margin. Proboscis very long and slender, reaching considerably beyond the tip of the abdomen when folded beneath the body, in which position it is in the type; while in the paratype it is directed downward with a slight anterior slant; labella thin and elongate. Palpi short and slender, distinctly three-jointed; the two apical segments much longer and of about equal length; the third truncate at apex. Body slender. Thorax about as broad as thick; dorsum dis- tinctly longer than wide; transverse suture deep on the sides over less than one-third t,he width of dorsum, continued back- ward to near the scutellum. Scutellum large, semi-elliptical, cushion-shaped; its posterior margin faintly separated from the disk by an impressed line. Abdomen flattened dorsally, slightly wider than the thorax; the four basal segments together about as long as wide; the succeeding, apical segments much narrower, gradually decreasing in width, partly retractile as a telescope-shaped ovipositor. The last segment ends in two short, slender, straight, bluntly pointed lamellae. Legs long and thin; femora slightly swollen toward the base. more distinctly so on the front legs; tips of tibiae faintly thickened. Wings very long and narrow, much longer than the body, over four times as long as wide. Costal margin nearly straight;



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19251 New Nemestrinidce from Rhodesia and New Guinea 11 the posterior margin much constricted in its basal quarter, where a very narrow trace of the alula extends from the axillary excision to the base of the wing. Wings very faintly infuscate all over; more distinctly yellowish grey in the costal cell and at the extreme base. Veins dark clove-brown; epaulet and basicosta nearly black; the epaulet mostly covered with black pile. Venation of the usual type of the genus; fourth posterior cell with a long petiole at base; sixth longitudinal vein faintly undulate (more so than in S. gracik Lichtwardt); no "bulla" at base of second vein; axillary vein not developed beyond axillary incision.
Length not including ovipositor (to apex of tergite 4)) 10.5 mm.; greatest width of abdomen, 4.5 nim.; length of proboscis, 14.5 mm.; length of wing, 14 mm.; width of wing, 3.4 mm. In the paratype these measurements are respectively 11 mm.; 5 mm.; 16 mm.; 15.5 mm.; 4 mm.
This species is allied to Stenobasipteron gracile Lichtwardt, also of Southern Rhodesia. From published accounts alone, it would have been difficult to point out the differences. For- tunately, I was able to compare specimens of the two species. The proboscis is decidedly longer in S. arnoldi, being always much over body length; the wings are narrower (in a female of 8. gracile they measure 14 by 4 mm.) and much less infuscated; the third segment of the antennae is decidedly shorter (in S. gracile it is about twice as long as wide at base and amply as long as the two basal segments together). Stenobasipteron diff icile sp. nov.
Type female from Cloudlands, 6,000 ft., Vunibu Mts., Southern Rhodesia, 6 to 17 April, 1923 (without collector). In the collection of the Rhodesia Museum.
A medium-sized, rather thickset, black species, covered with cinereous tomentum on the under side, with a black bloom on the upper side, the dorsal surface of the abdomen somewhat shiny. Antennae and legs reddish brown; the last antenna1 segment and the hind tarsi darker. Pilosity moderately long and dense on head, thorax and base of abdomen, yellowish white



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12 Psyche [ ~ e bruar
ventrally, pale russet dorsally. Proboscis about as long as the body. Wings moderately long, uniformly smoky all over. Female. Integument black even on the face; scutellum clove-brown. Two basal segn~ents of antennae reddish clove- brown; the last segment much darker; the style black. Palpi clove-brown. Proboscis brownish black. Legs reddish clove- brown; the tip of the tibiae and the tarsi more infuscated; the hind tarsi almost black; claws black.
Pilosity rather long and abundant on head, thorax, and base of abdomen. Vertex, front, and face with numerous, erect, black hairs; cheeks and posterior orbits with a long and dense beard of greyish white pile. Dorsum of thorax and scutellum uniformly covered with loose, erect, moderately long, reddish yellow pile, more russet on the scutellum; sides and ventral face with long and dense, greyish white hairs, more yellowish below the wings. Dorsally the abdomen bears on the first and basal half of second tergites long, erect, reddish yellow pile, similar to that of the thoracic dorsum; the remainder of the dorsal side bears many scattered, short and more or less appressed, black hairs; and in addition a very sparse, long, erect, black pilosity; ventrally there is on the sides a dense, yellowish white, matted pile, but the largest part of the sternites has but a very few, short, appressed, white hairs. Coxse and femora with long, erect, greyish white pile; the hairs on the tibiae and tarsi very short and black. The ground color of the integument on the ventral side of thorax and abdomen is completely hidden by a dull, cinereous white bloom. On head and dorsum of thorax the pruinescence is dull and very dark brown, somewhat more cinereous on the sides of the dorsum and on certain areas of front and face. The sides of the face rather shiny. On the
dorsal face of the abdomen the pruinescence is velvety black, with a somewhat oily sheen, and there are two transverse, ill- defined spots of a yellowish grey, dull bloom near the anterior margin of the second, third and fourth tergites, so that the abdomen appears quite distinctly spotted. Head moderately flattened, much broader than the thorax; semi-elliptical seen from above; in profile the face is moderately projecting, much less so than in S. arnoldi; when seen in front



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19251 New Nemestrinidce from Rhodesia and New Guinea 13 the head is kidney-shaped and nearly twice as wide as high in the middle. Front rather wide, broadest at the insertion of the antennae where it measures a little over half the width of the eye; inner orbits moderatlely converging toward the anterior ocellus, where the front is slightly over half as wide as at the antennae. Sides of the vertex parallel. Ocellar tubercle short and flat, with a slight transverse depression below its middle, hardly separated by a notch from the inner orbits; ocelli placed in a short isos- celes triangle, the posterior ocelli distinctly, but slightly, closer to each other than to the anterior ocellqs; anterior ocellus larger than, though not quite twice the size of, a posterior ocellus. short elliptical, occupying a little less than one-third of the width of the front.
Eyes bare. Antennae (Fig. 1b) short, small, placed on the sides of the face, close to the inner orbits; basal segment cylindrical, nearly one and a half times as long as wide, squarely truncate at apex; second segment but little shorter than the first, slightly longer than wide, broadly truncate at apex; third segment much flattened, very elongate pear-shaped, over twice as long as wide, much longer than the two basal segments together, widest in its basal half and thence rather rapidly tapering to the straightly truncate, narrow apex. Style
about the length of the whole antenna, only two-jointed; the basal division a little shorter than the second antenna1 segment. Front very feebly convex between anterior ocellus and antennae. Face moderately swollen, forming a low, blunt cone, without grooves. The lower port'ion of the head is but slightly and very broadly excavated in the middle between the cheeks. Proboscis very long and slender, reaching about the tip of the abdomen when folded beneath the body; in the specimen in hand it is directed vertically downward, with the apical third curved forward; labella very thin and elongate. Palpi short and slender, three-jointed; the two apical segments much longer and of about equal length; the third obtuse at apex. Body rather thickset. Thorax about as wide as thick; dorsuni nearly square; trans- verse suture deep on the sides over about one-third of the width of dorsum, continued backward to near the scutellum. Scu- tellum large, semi-elliptical, its posterior margin distinctly separated from the disk by an impressed line. Abdomen flat-



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14 Psyche [~ebruar~
tened dorsally, much wider than the thorax; the four basal segments together much shorter than wide; the succeeding, apical segments much narrower, gradually decreasing in width, partly retractile as a telescope-shaped ovipositor. The last segment ends in two coniparatively wide, long, straight, bluntly pointed lamellae. Legs moderately heavy; femora slightly thickened, more distinctly swollen on the forelegs. . Wings moderately long and narrow, not quite four times as long as wide. Costal margin nearly straight*; the posterior margin gradually narrowed in its basal quarter, where a narrow, but distinct alula extends from the axillary excision to the base of the wing. Wings distinctly and uniformly smoky; veins dark clove-brown; the epaulets and basicosta black; the epaulet with a few black hairs. Venation of the usual type of the genus; fourth posterior cell with a short petiole at the base; sixth longi- tudinal vein very slightly undulate (nearly as in arnoldi); no "bulla" at base of second vein; axillary vein not developed beyond axillary incision. '
Length not including ovipositor (to apex of termite 4), 11.5 mm.; greatest width of abdomen, 6.5 mm.; length of proboscis, 11.5 mm.; length of wing, 15 mm.; width of wing, 4 mm.
This species is exceedingly close to Stenobasipteron gracile Lichtwardt, much more so than S. arnoldi. There are, however, a number of differences: the body is more thickset; the legs are stouter; the anterior ocellus is smaller, not quite twice the size of a posterior ocellus; the third antenna1 segment has a different shape; the style is only two-jointed; the sixth longitudinal vein is quite straight; the lamella of the ovipositor are broader, etc. It is difficult to believe that these discrepancies are all due to individual variation. Moreover, the unknown male may show further characters.
Stenobasipteron gracile Lichtwardt
The original description of this species (Deutsch. Ent. Zeitschr., 1910, p. 615) is extremely brief and is reproduced here for the benefit of Rhodesian entomologists. It is said to be so



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19251 New Nemestrinidce from Rhodesia and New Guinea 15 similar to S. wiedernanni Lichtwardt, that only the differences are noted: "Smaller and more elegant in the whole build of the body; the color is markedly paler than in S. wiedemanni and has a more greyish tinge; while, the uniformly colored surface of the wing is also more smoky grey, showing but a narrow,-yel- lowish-brown stripe along the anterior margin. Sharp dif- ferences are the absence of the "bulla" in the wing of both sexes; the inequality in size of the ocelli, of which the anterior one is