Description of adults of Labiobaetis apache (Ephemeroptera: Baetidae) with additions and corrections to the inventory of Colorado mayflies

Male and female adults of Labiobaetis apache are described from specimens collected in northwestern Colorado, USA. Biological notes for this species are given and a key separating the male adults of the six North American species of Labiobaetis is provided. Additional Colorado distributions fort dardanus and Baetis notes are given. Cinygmula tarda is reported for the first time in Colorado.