St Mark's Fly vs Mountain Midge

Side-by-side species comparison

Attribute St Mark's Fly Mountain Midge
Scientific Name Bibio johannis Deuterophlebia coloradensis
Order Diptera Diptera
Family Bibionidae Deuterophlebiidae
Size 6-10mm 3-5 mm
Habitat Underground Mountains
Diet Root Feeders Herbivores
Regions Europe North America
Conservation Least Concern Least Concern

St Mark's Fly

A small black fly that swarms in May. Males have large heads with huge eyes that almost meet on top.

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Did You Know?

Often confused with the larger Bibio marci but emerges slightly later and has entirely dark legs.

Mountain Midge

A tiny midge whose larvae cling to rocks in fast-flowing alpine streams with suction discs.

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Did You Know?

Adults have bizarre fan-shaped wings that are useless for flight.