Spect&s of African Simuliidse. 73 



in others on hexagonal plates. In one species — S. gilvipes, 

 Pomeroy — the membrane is covered with crescent-shaped 

 nodules arranged in rows. In three species which have 

 pupse with four-branched filaments the resemblance in the 

 arrangement of the chitin is remarkable, since one species 

 (S. bracteatum, Coq.) is found in N. America, another 

 (S. aureum, Fries) is a British species, and a third {S. aureo- 

 simile, Pomeroy) is found in theKamerun, W. Africa. The 

 writer has not made any histological investigation into the 

 subject, aud some considerable work needs to be done before 

 any definite conclusion can be reached ; but from superficial 

 observation under a low power the characters seem to be 

 too important to be overlooked. 



In the following descriptions of new species the pupa? 

 have been correlated with the adults, by dissecting adult 

 males which were almost ready to emerge from the pupal 

 skin and comparing their genitalia with those of specimens 

 bred in the streams at the same time and place. 



Simulium cervicornutum, sp. n. 

 (PI. III. fig. 3 ; PI. IV. fig. 3.) 



Male. — Length 1/5 mm. 



Antenna black, covered with a short greyish pubescenc. 

 Thorax velvet-black, covered with thick golden pubescence, 

 in freshly emerged specimens entirely so. Pleura brown, 

 lacking the patch of soft hairs. Wings hyaline, veins brown, 

 radius unforked. Abdomen velvet-black, first segment with 

 a fringe of dark purple-brown hairs ; a diagonal perlaceous 

 stripe on each side of the abdomen across the fifth, sixth, and 

 seventh segments, rather more iridescent blue in some lights. 

 Legs : front legs, coxas dark brown ; femora, apical ends 

 dark purple-brown, remainder covered with shining light 

 yellow hairs; tibite, apical third dark purple brown, re- 

 mainder covered with light yellow hairs; tarsi almost black. 

 Hind legs: coxse dark purple-brown; femora dark purple- 

 brown ; tibiae, basal third covered with light shining yellow 

 hair ; tarsi purple-black, second tarsal joint with excision 

 near base. Genitalia: basal pieces large; claspers about 

 one-third the length of basal piece, having one finger-like 

 process at the apex ; anal plates, the lateral plates very long, 

 exceeding the length of the claspers, with a few short bristles 

 at the apex, the centre plate large ; adminiculum rather 

 broad, with a fringe of short hairs and some very irregular 

 short spines at the apex of the trough ; arms, the arms end 

 mesally with a pair of spines, the outer one very long, the 

 inner verv short. 



