Glacier Midge vs St Mark's Fly

Side-by-side species comparison

Attribute Glacier Midge St Mark's Fly
Scientific Name Diamesa steinboecki Bibio johannis
Order Diptera Diptera
Family Chironomidae Bibionidae
Size 3-5 mm 6-10mm
Habitat Rivers & Streams Underground
Diet Detritivores Root Feeders
Regions Europe Europe
Conservation Data Deficient Least Concern

Glacier Midge

A remarkable midge that completes its entire life cycle in glacial streams at temperatures near 0C. Represents one of the coldest habitats inhabited by any insect.

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Did You Know?

This midge lives its entire life in water barely above freezing — its larvae graze algae on glacier surfaces where temperatures hover around 0C year-round.

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.