142 



A. INGRAM AND J. W. S. MACFIE. 



developed, extending all the length of the ventral surface of the segment. The hairs 

 on the dorsal end of the anal segment are quadruple above and single below on each 

 side. 



This larva may be distinguished from the other known African Ochlerotatus larvae 

 (Edwards' key, Bull. Ent. Kes., hi, p. 376, and Bull. Ent. Res., vii, pp. 5-6) by its 

 possessing multiple mid-frontal hairs with a pecten of only 9-1 1 spines. 



Breeding place. — The larvae were found in a variety of situations, namely, in small 

 cavities washed out by the sides of cement drains running across an open and wind- 

 swept golf-course, in an empty grave in the Accra cemetery, in broken pipes, earth 

 drains, pools and crab-holes. Associated with them, A. costalis and C. thalassius 

 were frequently found, and once C. fatigans. 



Fig. 2. Larva of Ochlerotatus albocepJialus, Theo. ; head and end of abdomen ; 



a, mental plate. 



The larval stage appeared to be passed through very rapidly, as some of the 

 samples in which pupae predominated were taken from pools that could not have 

 been in existence more than three or four days. The attitude of the larvae when 

 at the surface of the water was characteristic, the body and the siphon tube being 

 almost in line or forming an exceptionally obtuse angle. 



Ochlerotatus minutus, Theo. (fig. 3). 



The head is small, narrower than the thorax (52 : 80), and not so highly chitinised 

 as the head of 0. albocephalus. The antenna is curved, slender and covered with 

 spicules ; it carries a tuft of subplumose hairs at its middle. The mid-frontal hairs 

 are peculiar in that they are delicately branched ; they are multiple, numbering 

 6-8. The ante-antennal tuft is composed of 9-10 plumose hairs. The mental plate 

 has a small median tooth and 9 lateral teeth on each side. 



