Rhodesian Asilidae (Diptera) and their prey collected by Mr. C. F. M. Swynnerton

1. The collection was made in 1911 and 1912 by Mr C. F. M. Swynnerton in pasture land, coffee plantations, forest and forest outskirts at 3800-3900 ft. on Mount Chirinda, South-east Rhodesia; a description of the locality is given. 2. 498 individual insects are recorded as the prey of 16 species of Asilidae. 3. The structural adaptations of the Asilidae for the capture of prey are described, and considered in relation to the size and texture of the insects captured. 4. The preponderance of Orthopterous prey (211 specimens) is largely due to the records for Alcimus setifemoratus and Philodicus swynnertoni. It is most probably the result of local abundance, method of hunting and structural adaptation for the capture of large-sized insects rathern than preferential selection. The Hymenoptera (89) consist chiefly of Aculeata. Diptera (74) are represented by only four families, the Asilidae and Bombyliidae predominating. The Lepidoptera (56) are mostly butterflies. The Hemiptera (35) included nineteen Cicadidae and the Coleoptera (23) representatives of six families. The remaining orders are poorly represented (3 Neuroptera, 2 Mecoptera, 2 Odonata and 1 Isopteron). 5. The records suggest that Alcimus setifemoratus especially attacks Lepidoptera. 6. Many of the insects captured as prey are species considered to be specially defended against the attacks of Vertebrates. 7. Male and female captors occur in approximately equal numbers, but this is largely due to an excess of males in three species; apart from these the remaining species show the same predominance of females noted in previous investigations.