33 



which they are enabled to maintain their position against the 

 strongest current. Frequently they will leave their support and let 

 themselves out into the stream anchored by threads of silk and 

 enabled by them to return. 



" When full-fed, they pupate in small pocket-shaped cocoons 

 attached to the support on which the larval stage has been 

 passed. 



" The adult emerges in a bubble of air and, having gained the 

 surface, at once takes wing. 



" Swarms usually consist almost entirely of females. The 

 males are not blood-suckers and are rarely seen in any numbers 

 far from their breeding-haunts. Sometimes, however, the first 

 swarms of the season are made up largely of males this was the 

 case in 1906. 



" The powers possessed by even the females of actually blood- 

 sucking are very limited, so far as human beings are concerned, as 

 they appear to be unable to pierce the skin except in places such as 

 immediately behind the ear, the forehead, etc. I have never seen 

 them gorged with blood even from these situations. They 

 nevertheless cause intense annoyance both by their habit of crawling 

 into the eyes, ears and nose, and also by continually pricking the 

 skin in their ineffectual efforts to obtain blood. 



" They feed mainly on birds and animals. 



" On alighting upon a suitable host e.g., a donkey the fly 

 creeps down through the hair until it reaches the skin, whereupon 

 it inserts its proboscis and commences to suck blood. In a short 

 time its abdomen becomes enormously distended and the insect 

 then makes its way back out of the hair and attempts to fly. 

 Usually, owing to the quantity of blood it has imbibed, it is unable 

 to proceed more than a few yards before falling to the ground. It 

 then hides itself among the vegetation until the immediate effects 

 of its feast have passed away. 



" When walking over a smooth surface, the Nimitti wave their 

 forelegs, apparently using them as feelers. This habit is common 

 to many of the larger Tabanidce. 



' The first swarms usually make their appearance towards the end 



p 



