7 8 T. OKADA 



Drosophila (Hirtodrosophila) tripartita sp. n. 



(Text-figs. 262-267, p. 90) 



o\ $. Body about 2-2 mm. Head as broad as thorax. Eyes deep red, fusiform in lateral 

 aspect, with thick pilosity. Antennae orange-yellow ; third segment fuscous at tip, oval, much 

 broader than second segment, slightly longer than broad. Arista with about four dorsal and two 

 ventral branches and a large terminal fork. Palpus yellowish orange, with an apical seta. 

 Ocellar triangle small, deep reddish brown. Periorbit glossy grey-brown, anteriorly somewhat 

 curved inward, posteriorly slightly broadened and paler. Front orange-grey, paler anteriorly, 

 nearly parallel-sided, frontal triangle fuscous, anteriorly broader than length down middle, 

 posteriorly about four-sevenths as broad as head width. A few frontals present. Clypeus dark 

 brown. Carina long, low, broadened below to reach buccal margin. Cheeks orange-yellow, 

 broad, about two-fifths as broad as the greatest diameter of eye. Occiput yellowish brown, 

 ventromedially fuscous. Postvertical very long, much longer than outer vertical. Anterior 

 reclinate orbital about one-third as long as posterior reclinate, slightly nearer to proclinate than 

 to posterior reclinate. Proclinate slightly shorter than posterior reclinate, inside others. Only 

 one pair of long vibrissae, second oral one-fourth as long as vibrissa. 



Mesonotum glossy dark reddish brown. Scutellum dark reddish brown, unicolorous. Thor- 

 acic pleura paler than mesonotum. Two humerals, lower longer. Acrostichal hairs in six rows. 

 No prescutellars. Anterior dorsocentrals nearly half as long as posteriors ; distance between 

 anterior and posterior dorsocentrals about five-ninths distance between anterior pair. Anterior 

 scutellars divergent, longer than posteriors, which are nearer to each other than to anteriors. 

 Sterno-index about 05 ; sternopleurals situated close to each other. Legs yellow ; all meta- 

 tarsi as long as other segments together. Male fore leg without sex-combs ; mid leg without 

 hooked scaly bristles. Preapicals on all legs ; apicals prominent on mid leg. Wings hyaline, 

 crossveins clear. Costa reaching M. i? 2 + 3 gently convex at middle, gently curved to costa at 

 tip. ^? 4 +5 and M parallel. C-index about 38 ; 4.V-index about i-6 ; 4.C-index about o-6 ; 

 5x-index about 17 ; Ac-index about 21. Ci-bristles two ; C3-fringe on basal three-eighths. 

 Halteres yellowish orange, stalk paler. Abdominal tergites mostly dark brownish black, some- 

 what glossy ; iT and 2T anteriorly yellowish orange ; terminal T greyish white. 



Periphallic organs : Genital arch pale yellowish orange, setigerous and pubescent, dorsally 

 gently narrowing, medially swollen, ventrally tapering triangularly. Clasper dark brown, 

 oblong, with a sinuous row of about thirteen black pointed teeth occupying nearly entire length 

 of outer margin, and with a few short fine setae on inferior surface of distal half. Anal plate 

 pale yellowish brown, fusiform, separated from genital arch, pubescent and shortly setigerous, 

 lower tip pointed ventrally and with about five strong black bristles in a clump. Phallic organs 

 yellowish brown. Acdeagus rod-shaped, hairy, apically somewhat broadened, proximally 

 much swollen. Anterior paramere slender, curved, tapering, orange-brown, basally contiguous 

 with hypandrium. Posterior parameres fused to form a large quadrate flap, distal and proximal 

 margins medially concave. Ventral fragma triangular, pale brown, with deep median notch. 

 PI = 2-3. p.f. = aBcDEf gHiKlMN. Egg-guide lobe triangular, proximally narrowing, 

 yellowish orange, with about seventeen marginal and twenty-two discal short scattered yellowish 

 orange bristles on distal half. Subterminal hair short but distinct. Basal isthmus short. 



Holotype $. East Nepal : Taplejung District, Sangu, mixed vegetation by- 

 stream in gully, c. 6,200', xi. 1961-1.1962 (R.L.C.), BMNH. 



Allotype $. Same locality as holotype, ix-x.1961 (R.L.C.), BMNH. 



Paratypes : Taplejung District, 1 £, same data as holotype ; 1 £, between Sangu 

 and Tamrang, mixed shrubs in deep gorge, c. 5,200', x-xi.1961 ; 1 $, above Sangu, 

 mixed vegetation in dried-up ravine, c. 6,800', 16. ii. 1962 (R.L.C.), BMNH, (2 <J), 

 and at the Tokyo Metropolitan University (1 <$, between Sangu and Tamrang). 



