S VST K OPUS. 293 



ninth segment (which latter is peculiar to the <$ only, in accord- 

 ance with Osten-Sacken's views in the Biol. Cent.-Amer., Dipt, 

 i, p. 157), consists of an orange process bearing an upper pair of 

 jet-black conical claspers, there being also an orange-coloured 

 plate projected from the eighth segment, bearing a very small pair 

 of black conical claspers at the tip. Legs. Coxae : fore pair wholly 

 pale } r elIowish white, bare ; middle pair yellowish white, with a 

 large black mark on the outer side, on the basal half, and bearing 

 a few dark hairs ; hind pair black, with a little pale colour on inner 

 side below. Femora: fore pair pale yellowish white, with a dark 

 brown streak behind, about the middle ; middle pair black, ex- 

 treme base and tip pale yellowish white ; hind pair with basal 

 half pale 3 r ellow. deepening to orange on the apical half, extreme 

 base black above. Tibia? : fore pair pale yellowish white, bare ; 

 middle pair similar, but with a few very black spines at the tip ; 

 hind pair yellowish orange, streaked here and there with black 

 above, with irregularly-placed black spines, and with a circlet of 

 some short black spines at the tip. Tarsi : anterior ones pale 

 yellow, upper side blackish on apical half ; hind pair black, 

 minutely pubescent, slightly yellowish at extreme base, and with 

 a row of minute black spines below. Wings light brownish grey, 

 unmarked ; halteres lemon-yellow. 



Length, 17-23 mm. 



I described this species as nigricaudus from a S and § in the 

 Indian Museum from Soondrijal, Nepal, and Mussoorie respec- 

 tively, and a second $ in the Pusa collection also from Mussoorie. 

 Further specimens from Ivalimpong, Darjiling Distr., 600-4500 ft., 

 24. iv.-lu. v. 1915 {Gravely): Peshoke Spur, Darjiling Distr. 

 (Lister); Mussoorie, ix. lyOo ; Shillong, 4900 ft,, 27. vi. 1918. 



After the careful examination of several specimens there seems 

 no doubt that my nigricaudus is identical with opliioneus, which 

 appears to show considerable variation in the extent of yellow in 

 the antennae, the size and extent of the thoracic spots and their 

 frequent, union by short connecting-bands, and in the presence 

 or absence of the streak on the middle tibiae, besides minor 

 differences. 



In the type of nigricaudus (Nepal) the ] st antennal joint and 

 basal half of 2nd is yellow ; the thoracic spots, three on each side 

 of the dorsum, quite separate, the humeral one reaching down to 

 the front coxae ; the scutellum is wholly black ; the 1st abdominal 

 segment also all black ; the four anterior femora have more than 

 the basal half black ; the fascia on the middle tibiae is not obvious, 

 but the inner side from base to tip bears minute black bristles. 

 In another specimen (Darjiling) the first two antennal joints are 

 yellow ; the spots on the humeral, prealar, and posterior calli are 

 joined by a distinct yellow band, the anterior spot extending 

 broadly to the fore coxae ; the scutellum is all black, except for a 

 distinct yellow hind margin ; the first abdominal segment all 

 black ; the fascia on the middle tibiae absent. In a third specimen 

 (Kalimpong, Darjiling District) the antennae are black, except the 



