St Mark's Fly vs Cuckoo Wasp

Side-by-side species comparison

Attribute St Mark's Fly Cuckoo Wasp
Scientific Name Bibio johannis Chrysis ignita
Order Diptera Hymenoptera
Family Bibionidae Chrysididae
Size 6-10mm 6-12 mm
Habitat Underground Underground
Diet Root Feeders Nectar Feeders
Regions Europe Europe, Asia
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.

Cuckoo Wasp

A stunning metallic jewel-toned wasp that lays eggs in other wasps nests. Can curl into an armored ball when attacked. Its iridescent colors are among the most vivid in nature.

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Did You Know?

Cuckoo wasps have an armored concave underside — when discovered by the host wasp, they curl into a perfect shiny ball that the host cannot sting through.