Abstract

The 1st blind, depigmented, aquifer-adapted water beetle of the family Dytiscidae is described from North America. Haideoporus texanus Young and Longley (n. genus, n. sp.) is superficially similar to Morimotoa phreatica Uéno from Japan, but differs in possessing minute, apparently nonfunctional eyes, and in sensory setal vestiture and structure of the tarsi and external male genitalia. The remarkable similarity of the fore and middle coxae and the relationship of the prosternal process to the metasternum among Haideoporus, Morimotoa, and Siettitia (a cave-adapted genus from southern France) is thought to be due to convergence as an adaptation to subterranean life parallel to the condition seen in many cave carabids (Coleoptera: Carabidae). The world fauna of subterranean aquatic beetles and the associates of Haideoporus are discussed.