PUPAL STAGES OF WEST AFRICAN CITLICID.E. 27 



5. Stegomyia africana, Theo. 



Lap A' A. 



The head is rather small and peculiar in shape, dark in colour and very 

 chitinous. Viewed both dorsally and ventrally, the brush, which is so pro- 

 minent in the Anopheline and other larvae, does not show, or is only partially 

 visible. The antennae are without plumes, and only carry a few short hairs 

 at the end. Face without plumes, and with only short stellate hairs on each 

 side o£ the median line, and two longer ones, which appear to be split at their 

 ends, or they may possibly be two hairs ; all these are simple. 



Thorax rather small, with the usual plumes, but these are of simple hairs ; 

 the dorsal anterior hairs are short, and also simple. Some of the side plumes 

 are slightly pubescent at the base. The plumes on the ventral anterior sides 

 or ends of the thorax have chitinous sockets and a rather prominent bristle 

 at the base. 



The abdomen is long and thin, and is symmetrically studded with an arrange- 

 ment of short triple hairs on the dorsum, and several long simple hairs on 

 each segment (PL III, fig. 3). It is very difficult to get a view of the sub- 

 siphonal and siphonal plumes, but they consist of but a few simple hairs in 

 the usual places ; the relative proportions are the same as usual, the siphonal 

 being smaller than the sub-siphonal. Yiewed dorsally the combs appear as a 

 series of short spines on each side of the eighth segment, but a lateral view 

 shews them as a single row of about ten scales. 



The best way to see the lateral view of the siphon is to projj the larva up 

 with a piece of fine bent wire or entomological pin. It is only slightly over 

 twice the length of the base ; the spines run in a curve, very close to each 

 other, and are at least 12 in number ; at their upper end is a double hair ; 

 the valves are small (PL III, fig. 4). 



The anal segment is short, with the papillae a little longer, subequal and 

 with very stout bases ; the hairs on the dorsal edge are long, but the ventral 

 beard is scanty, consisting of only a few simple hairs. 

 Larva about 4 mm. in length. 



The following is a description of two immature larvae of the same species : — 



Head very large, dark and chitinous ; in one specimen it is darker than in 



the other, which is much lighter. Antennae small and without plume ; no 



plumes on the face, only single or stellate hairs ; it has also the two split hairs 



found in the previous form, which it much resembles in the head. 



Thorax rather small ; instead of the anterior hairs it has four large stellate 

 hairs ; it is also studded with simiLar hairs on all the sides, and has longer 

 single hairs standing out from the shorter stellate ones. These single hairs 

 are also collected, as in the mature stage, into plumes with a strong bristle at 

 their base, and are shghtly pubescent on their lower part (PL III, fig. 7) ; 

 they occur in both stages also on the ventral side. 



