Condylostylus tonsus

Difficult to distinguish from other Condylostylus species without examination of male genitalia. The genus Condylostylus is recognized by metallic coloration, long legs, and typical dolichopodid body plan. Within the family, Condylostylus is distinguished from Dolichopus by the absence of specialized tarsal scales on the male forelegs used in courtship displays. From Medetera, it differs in habitat preference (foliage vs. tree trunks) and leg proportions.

Small fly with metallic green, copper, or bronze coloration typical of the genus. Body length approximately 5 mm or less. Long, slender legs characteristic of Dolichopodidae. Males possess forward-protruding clasping appendages at the abdominal tip, visible as curled structures beneath the abdomen.

Found in gardens, along forest edges, and similar sunny habitats with vegetation. Associated with foliage where it actively hunts small prey.

North America; specific records include Illinois. Distribution details beyond this are not well documented in available sources.

Predatory on other small insects. Prey captured using modified labellum (extendable lower lip with opposable lobes) rather than beak-like mouthparts.

Larval biology unknown for this species. Larvae of related dolichopodids are generally predatory, with many species having aquatic or semi-aquatic larvae.

Highly active, rarely pausing movement. Rapid, darting flight over leaves in sunny conditions. Sensitive to disturbance, including camera pre-flash, often resulting in immediate departure. Males display to females using genital claspers in complex courtship.

Predator of small insects in vegetation communities. Potential biological control agent in garden and agricultural settings.

Valued as beneficial garden ally due to predatory habits. Subject of interest for macrophotography, though challenging to capture due to rapid movement and sensitivity to disturbance.

• Dolichopus speciesLack specialized ornamented foretarsi in males; Condylostylus males lack the scaled tarsal flags used in courtship displays by Dolichopus
• Medetera speciesAssociated with tree trunks rather than foliage; Medetera species adopt distinctive 'tiptoe' posture on vertical surfaces
• Hydrophorus speciesAssociated with water surfaces, skating on puddles and lake margins; Condylostylus is strictly terrestrial on vegetation

• predatory
• metallic
• beneficial insect
• difficult to photograph

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