pupal stages of west african culicid.e. iij 



The Lower Lip. 



This part is very similar in botn Anopheline and Ciilicinc larvse, being 

 a striking, much chitinisod, serrated shield, which lies in the median line o£ 

 the under side of the head (PI. lY, 6o-. ?)). 



The Face. 



This part, the dorsal front of the head, varies in size and character, as well 

 as in the number of the plumes ; pigment-spots are often present, especially 

 two half-moons near the bases of the brushes. 



There are usually six plumes on the fore part of the head, each haA'ing 

 from three to eight hairs ; and behind these are four minute stellate hairs,, 

 flanked by two longer plumes (PL IT, fig. 11). 



The Eyes. 



The eyes are variable in shape ; in some stages of the Anophelines 

 examined they were reduced to small round bodies, but in others they are of 

 a sub-lozenge or half-moon shape, and have often a small pigmented mass 

 of eye-structure behind. As, however, the eyes appear to undergo great 

 changes in the larval moults, these characters are unreliable, and it is best 

 to record only the condition of the mature forms. 



The Thorax. 



The relative size of this part undergoes many changes, particularly in the 

 Anopheline larva?, but the plumes on it are fairly constant. It must be 

 examined on both sides ; the dorsal anterior edge has many plumose hairs 

 which often reach forward, quite over the head, and there are two pairs of 

 plumes behind these and two on the shoulders (PI. II, fig. 11). 



The majority of the plumes are on the ventral side, and three or four 

 hairs usually spring from a chitinous tubercle. All these plumes in some 

 measure accentuate the three segments of the thorax (PI. II, fig. 10). 



In the mature larvre of Pyretoplwrus costalis, Lv>^_, there is a regular and 

 geometric pattern on the ventral side, and this character appears confined to 

 the mature larval stage (PL YI^ fig. 1) . 



The Abdomen. 



The abdomen consists of nine segments of which the first two bear plumes, 

 usually of a similar character to those on the thorax. The dorsum is studded 

 with innumerable combinations of small and large stellate and other hairs, 

 but except when the part is unusually hairy, as in Stegomyia africcuia, Theo, 

 (PL III, fig. 7), the characters are rarely specific. The eighth segment is, 

 however, a striking exception, as it bears on each side a patch of spines 

 known as the comb and on the dorsum the highly important siphon or 

 respiratory tube ; the ninth or anal segment is also of great use on account 

 of its appendages. On the posterior side of the siphon, and usually on the 

 membrane between the eighth and anal segments, are two plumes, usually 



