152 



R. W. CROSSKEY 



97 



99 



101 



102 



103 



104 



105 



107 



Figs. 96-107. Form of the ventral plate of $ genitalia in subgenera and species-groups of 

 African Simulium. 96-98, Pomeroyellum, alcocki-group. 99, Pomeroyellum, cervicorn- 

 utum-group. 100, Eusimulium, latipes-group, 101, Eusimulium, ruficorne-group. 102, 

 Eusimulium, aureum-group. 103, Eusimulium, loutetense-group. 104, Xenosimulium. 

 105, Lewisellum. 106, Phoretomyia. 107, Byssodon. 



