that spi^ead Disease. 



25 



grown. The maggot of G. j)al'j)ali8 is dropped by the mother in a 

 shady place near water, where the soil is loose or sandy, moderately 

 dry, and often consisting of crumbling vegetation. On being 

 deposited, the maggot buries itself in the loose earth; its skin 

 then becomes dark in colour, contracts, and hardens into a barrel- 

 shaped puparium or case, within which the change to the pupa or 

 chrysalis takes place. A female fly of this species may produce 

 from eight to ten larvae altogether, one at a time at intervals of 

 nine or ten days. 



Fig. 6.— a Tsetse-Fly that speeads Sleeping Sickness, 

 Glossina palpalis, female, X 5. 



Specimens of Glossina palpalis are shown in the attitude in 

 which they rest. X resting tsetse-fly can be distinguished from 

 any other blood-sucking fly with which it could possibly be 

 confused by the fact that the wings, instead of diverging at the 

 tips, lie closed flat over one another down the back like the blades 

 of a pair of scissors, while the proboscis with which the bite is 

 inflicted projects horizontally in front of the head. 



Glossina morsilans Westw. is a widely distributed tsetse-fly 

 (see map), spreading nagana among domestic animals, and i 

 Nyasaland and Northern Rhodesia conveying to man th 



