FLIES 315 



abundant in some parts of the country. So that the 

 islands would appear to be unfavourable to them. 



One large species was found on Damba under a stone 

 at the very water's edge, so that the tiniest ripple must 

 have surrounded it. 



DiPTERA. 



The most important fly on the islands, namely Glossina 

 palpalis, has had a chapter to itself. Other biting flies 

 {Tabanidae) were less common on the islands than on 

 the mainland, but T. variabilis a small black and white 

 species, and Chrysops brucei were occasionally seen, with 

 one or two species of Hcematopota. 



Mosquitoes, of course, were to be reckoned with, and 

 they were particularly abundant on Damba Island, 

 perhaps because it was covered with low lying forest. 

 But the Anophelines, carriers of malaria, were so 

 scarce that the numbers of times one was seen could 

 be counted on the fingers, so that the health of the party 

 was excellent. The Simuliidae, or " Buffalo gnats," have 

 been alluded to as particularly troublesome on certain 

 islands when rain was threatening ; they frequent rocky 

 open shores, and when abundant render such spots un- 

 approachable. The species found on the islands was 

 not the same as the one I had previously met at Jinja, 

 S. damnosum, called " Embwa " by the natives ; the 

 island Simulium is smaller and rather prettily coloured 

 with golden pubescence. Both leave a severe burning 

 and itching sensation, but whereas S. damnosum attacks 

 particularly the lower extremities, the island species 

 makes for one's head and neck, and especially the ears. 



The parasitic Tachinidae, which lay their eggs on the 

 surface of living insects, have been briefly alluded to as 

 enemies of " protected " insects. 



On one occasion a species was observed in the act of 

 oviposition. 



