St Mark's Fly vs Bristly Tachinid Fly

Side-by-side species comparison

Attribute St Mark's Fly Bristly Tachinid Fly
Scientific Name Bibio johannis Nowickia ferox
Order Diptera Diptera
Family Bibionidae Tachinidae
Size 6-10mm 12-16 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.

Bristly Tachinid Fly

A large, heavily bristled tachinid fly with a gray-checkered pattern on the abdomen. It is conspicuously spiny and frequently visits flowers in late summer.

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Did You Know?

Its exceptionally long and stiff bristles are thought to help prevent birds from swallowing it.