Orohermes crepusculus

Orohermes crepusculus can be distinguished from other western North American Corydalidae by its relatively small size within the family and specific genitalic characters. Males possess distinctive claspers that differ from congeners such as Orohermes maximus and Orohermes arizonensis. The forewings are relatively broad with characteristic venation patterns typical of the genus, including numerous crossveins and a well-developed anal area. Separation from the closely related genus Dysmicohermes requires examination of male genitalia and wing venation details.

Western North America, with records from the southwestern United States including Arizona and adjacent regions. The distribution appears to overlap with other Orohermes species in the arid and semi-arid regions of the American Southwest.

Adults have been observed to be attracted to artificial light sources, a common behavior in Corydalidae. The species name suggests potential crepuscular (twilight) activity, though this has not been explicitly documented in published sources.

Larvae of Corydalidae, including Orohermes, are predatory aquatic insects that occupy rocky stream habitats. They function as intermediate predators in freshwater food webs, consuming smaller invertebrates and serving as prey for fish and other aquatic vertebrates.

• Orohermes maximusLarger congener with overlapping distribution in western North America; distinguished by size and male genitalic morphology
• Orohermes arizonensisSympatric congener in Arizona; requires genitalic examination for reliable separation
• Dysmicohermes spp.Closely related genus with similar overall morphology; distinguished by wing venation and male genitalic characters

• Megaloptera
• Corydalidae
• fishfly
• western North America
• aquatic insect
• predatory larva

• BugGuide
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life