Immature stages of some eastern Nearctic Tabanidae (Diptera). I. Introduction and the genus Chrysops Meigen.

During the past four years, approximately 1100 larvae and pupae of horse and deer flies were collected from 9 States in the south-eastern United States and adults of 29 species in 6 genera were reared from them. Immature forms of 11 species lent to the author were also studied. Descriptions of the larva and pupa of Chrysops flavidus subsp. reicherti Fairchild, of the larva of C. divisus Wlk. and of the pupa of C. atlanticus Pechuman are presented, together with comments on 8 additional species of Chrysops. Keys to the genera of the known larvae and pupae are given. The keys and introductory material refer not only to the present paper but also to at least two future ones in which elements within the subfamily Tabaninae will be discussed.