MUSCIDiE: THE BLOOD-SUCKING MUSCID^ 171 



These suitable conditions include shade of some sort, a 

 shade-temperature of about 85° Fahr., and the proximity of 

 water to provide a fairly humid atmosphere. Though shade 

 is indispensable, the fly is not active after sunset or in cloudy 

 weather; though a moist atmosphere is indispensable, a 

 water-logged soil is obnoxious, since the pupa has been 

 shown, by Bagshawe, to require a light well-drained crum- 

 bling soil for its development ; and though the propinquity of 

 water is essential, the fly is known to follow travellers, both 

 by road and rail, for a considerable distance from its riverside 

 haunts. 



Glossina palpalis is said to feed on the blood of any kind 

 of mammal, and also to attack birds, reptiles, amphibia, and 

 even amphibious fishes like certain gobies. 



As regards reproduction, Roubaud, from observation of 

 captive flies, found that the first larva was dropped about 

 three weeks after coupling, and that other larvae followed at 

 intervals of nine or ten days. He also noticed that the 

 larva transformed to a pupa in about three-quarters of an 

 hour; that the pupal stage lasted, in suitable conditions, 

 thirty-two to thirty-five days ; and that pupae were killed by 

 prolonged burial in damp earth, or by several hours exposure 

 to a hot sun even though covered with 2 inches of dry earth. 

 Bagshawe observed that, in nature, pupae of G. palpalis were 

 to be found, more than an inch below the surface of the 

 ground, in well-drained humus, sheltered by trees or bush, 

 within 25 yards — commonly within 10 yards — of water; twice 

 he found pupse in crevices in rock, and twice between the 

 buttress-roots of fig-trees. On the shores of Lake Victoria 

 Nyanza, Marshall and Fraser found the pupae in sand. 



It is no part of our scheme to summarise the existing 

 knowledge of this species as a pathogenic medium. It is 

 sufficient to mention that whatever other species of Glossina 

 may, in some particular locality, be hereafter shown to be 

 implicated, G. palpalis is the species that the illustrious 

 Bruce and his coadjutors first proved to "carry" the 

 trypanosome of sleeping-sickness, and that is now believed, 

 with good reason, to be the usual infective agent in spreading 

 that appalling disease. Kleine followed with proof presump- 

 tive that the part played by the fly is not chiefly a mechanical 



