Onchopelma brevifasciatum Evenhuis

Evenhuis, Neal L., 2002, Review of the genus Onchopelma Hesse, with descriptions of new species (Diptera: Mythicomyiidae), Zootaxa 64, pp. 1-12 : 3-5

Onchopelma brevifasciatum Evenhuis , sp.n.

( Figs. 1, 2 , 10 )

DIAGNOSIS. Males of this species are most similar to O. pulchellum , but can easily be separated from it by the absence of a hook on the hind basitarsus (present in pulchellum ). Females are most similar in appearance to O. majus , sp.n. but can be distinguished from that species by the presence of lateral black spots on the abdominal tergites (these spots absent in majus , sp.n.) and the frons yellow to white on the lower half and black on the upper half (all yellow in majus , sp.n.).

DESCRIPTION. Female. Length: 2.90–3.25 mm. Head ( Fig. 2 ) higher than long; eyes dichoptic, separated at vertex by 1.5 x distance between lateral ocelli; vertex black; occiput black dorsomedially, white ventrolaterally and ventrally, with sparse white hairs, densest laterally; frons white on lower half, black on upper half as extension of black color from vertex; face and tip of oral margin white; antenna with scape short, subtrapezoidal, yellow­white with some brown color dorsally; pedicel subrectangular, slightly longer than wide, brown; first flagellomere linear, length ca. 4 x than width, brown; second flagellomere linear­ovate, slightly shorter than first flagellomere, brown with small transparent apical style; proboscis brown, length slightly less than head length; labrum sclerotized, stiff, pointed apically; palpus not evident.

Thorax. Mesonotum white with black patterning as in Fig. 2 , short sparse white hairs on humeral and prescutellar areas; pronotum black; scutellum white with sparse white hairs; pleura white except for black on katepisternum, meron, and mediotergite; coxae and legs white; halter stem and knob white.

Wing. Hyaline; veins pale yellowish; costa ends slightly beyond end of R4+5; vein Sc incomplete; M1 and M2 evanescent toward wing margin; crossvein dm­cu closing cell dm absent; CuA1 closing anal cell before wing margin leaving stalk; stalk length slightly less than length of crossvein bm­cu; fringe of hair on posterior margin of wing in alular lobe and anal lobe areas sparse.

Abdomen ( Fig. 2 ). White; tergites with black transverse bands on segments 1­3, black on remaining segments as medial spots and lateral black spots; tergites with sparse short white hairs dorsally, longer and denser laterally; venter yellowish white.

Genitalia ( Fig. 10 ). Spermatheca unsclerotized, long, flared toward apex, reminiscent of the shape of some Nepenthes ; spermatheca with small basal bulb leading to apical duct; apical spermathecal duct very thin, transparent, length ca. 1.5 x length of spermatheca; sperm pump very short, with mushroom­shaped basal valve (sclerotized brown) and transparent flat, disc­shaped apical valve; basal duct short, slightly sclerotised brown.

Male ( Fig. 1 ). Same as female except for the following: eyes holoptic; head and abdomen predominantly all black; thorax black except for yellow­white humeral areas (not evident in dorsal view).

Types. Holotype male and one paratype female from: NAMIBIA [OMARURU]: Brandberg: Hungorob Valley , 1180 m, 21°11.40'S, 14°31.69'E, 05–16.iv.1999, S. van Noort & S.G. Compton, yellow pan trap, bushy Karoo­Namib shrubland. NA99­Y90 ( NMNW) . Other paratype: 1 female, KHORIXAS: Tweespruit 712: Khoadi/Hôas D4 , 20°05'59"S 14°12'26"E, 25–28.v.2001, E. Marais & A. Kirk­Spriggs, yellow pans ( NMNW) . Holotype and paratypes deposited in NMNW. Holotype, one topotypic paratype, and the Khorixas paratype preserved in spirit. One Brandberg paratype used for dissection pinned on point; female genitalia preserved on slide no. 20020811­1.

Etymology. The species epithet derives from the Latin brevis [= short] + fascia [= line] and refers to the relatively short black transverse stripes of the abdominal tergites in the female.

Figures

FIGURES 1 ­ 4. Onchopelma, dorsal view (wings removed), showing color pattern of head, thorax, and abdomen. 1. O. brevifasciatum, sp. n., male. 2. O. brevifasciatum, sp. n., female. 3. O. irwini, sp. n., female. 4. O. karooanum Hesse, female paratype.

FIGURES 10 ­ 11. Onchopelma female genitalia. 10. O. brevifasciatum, sp. n. 11. O. majus, sp. n.