HUMAN TRYPANOSOMIASIS 



145 



full growth in the ovary, and after being passed do not 

 feed but pass into the ground and become pupae. As the 

 larvae are still, motile and only ready to pupate, the flies 

 are rather larviferous than pupiparous. 



G. palpalis can be easily distinguished from other 

 common Glossinae, as the last four joints of the hind legs 

 are entirely black. Two other species have this character, 

 G. pallicera and G. uiaculata, whilst in G. tacliinoides the 

 last four joints, though black, are not entirely so. The 

 commoner species, G. morsitans, has only the last two 

 joints of the hind legs black. 



FlG. 43. Glossina morsitans. 



Without going into detail, then, Glossinae are flies which, 

 when alive, are readily recognized by the straight, long 

 proboscis projecting out in front of the head, and by the 

 crossed position of the wings of the insect when at rest. 

 These wings are always longer than the abdomen, and 

 projecting beyond it give the insect the appearance of 

 being longer than it really is (fig. 43). 



Glossinae bite mainly in the daytime, though some species 

 also bite at night. The bite is painful at the time, feeling 



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