398 



W. M. ADERS. 



Tabanus prodticticornis, Aust. One specimen captured on the sea-shore near a 

 mangrove swamp. 



Tabanus albipectus, Big. A few specimens obtained from a sandy bank near the 

 sea-shore. 



Aegophagomyia pinigens, Aust. A common species along the littoral of both 

 islands. These insects seem to have a marked preference for damp sandy patches, 

 often alighting to drink ; in comparison with other species they are but little affected 

 by high wind. I have no record of their attacking man, but on several occasions 

 they have been noticed feeding on goats. 



Adersia oestroides, Karsch. Similar in its habits to Aegophagomyia jningens ; numbers 

 have been taken in close proximity to carcases of cattle. Never known to bite man. 



Haematopota decora, Walk. The only species of this genus taken in Zanzibar. 

 It is prevalent throughout the whole year on both islands, and generally feeds on 

 the hocks and withers of cattle ; engorgement averages 2\ minutes. This insect 

 lives moderately well in captivity, and has been used on many occasions for trans- 

 mission experiments. 



Chrysops longicornis, Macq. A very common species in both islands, persistent 

 throughout the year. Many specimens were taken in a deep shady valley in Pemba ; 

 as many as thirty were captured in a few minutes on one donkey, its withers and 

 hocks being smothered. Once they have started feeding nothing disturbs them, 

 and they must almost be brushed off. Fully engorged specimens are slow of flight, 

 proceeding a few yards, then settling on any convenient foliage. They readily 

 attack man, inflicting painful bites round the ankles. 



The following is a chart showing the seasonal incidence of the common Tabanidae. 

 In all cases the collections were made from two water-buffaloes, two hours being 

 devoting to collecting. The majority were obtained from the Bububu district. 



0-31 

 0-88 

 2-58 

 4-22 

 3-20 

 1-31 



