Abstract
The genus Gryon Haliday in North America is revised. Twenty-seven species are recognized, 12 of them new to science: G. aculeator, G. acutiventre, G. atrum, G. chelinideae, G. elatior, G. longipenne, G. obesum, G. radiculare, G. stewarti, G. triangulum, G. vitripenne, and G. xanthosoma. The tribe Gryonini is discussed, and a key to North American genera of the tribe is included. A generic diagnosis of Gryon is given, and seven species-groups are discussed and(or) proposed. A key, diagnoses, relationships, and bionomics of species in North America are given. New terms for additional characters found on the posterior surfaces of the head are defined and figured.