Dolichopus tonsus

Identification to species within the genus Dolichopus is difficult and typically requires microscopic examination of male genitalia, specifically the claspers and other terminalia which protrude forward from the abdomen tip. Males of most Dolichopus species, including D. tonsus, possess modified front tarsi with special scale-like ornaments that may resemble tiny flags; these are used in courtship dances. The genus can be distinguished from other dolichopodid genera by a combination of leg proportions and wing venation, though specific characters for D. tonsus are not well documented in general sources.

Documented from North America; specific range details are sparse in available sources. The genus Dolichopus is broadly distributed across the continent.

• Other Dolichopus speciesNearly indistinguishable without examination of male genitalia; all share metallic coloration, elongated legs, and predatory habits.
• Condylostylus speciesAlso common metallic green dolichopodids, but Condylostylus species have different leg proportions and lack the modified front tarsi of male Dolichopus.
• Hydrophorus speciesSurface-skating dolichopodids with shorter legs and different habitat preferences; Hydrophorus species are more commonly associated with water surfaces.

• Diptera
• Dolichopodidae
• predatory fly
• long-legged fly
• metallic fly

• BugGuide
• GBIF taxonomy match
• iNaturalist taxon
• Catalogue of Life
• Bug Eric: Long-legged Flies