St Mark's Fly vs Firefly

Side-by-side species comparison

Attribute St Mark's Fly Firefly
Scientific Name Bibio johannis Photinus pyralis
Order Diptera Coleoptera
Family Bibionidae Lampyridae
Size 6-10mm 10-14 mm
Habitat Underground Underground
Diet Root Feeders Nectar Feeders
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.

Firefly

Famous for bioluminescent signals produced by a chemical reaction in their abdomen. Each species has a unique flash pattern used for mate recognition.

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Did You Know?

Firefly light is the most efficient in the world — nearly 100% of the energy is emitted as light, compared to only 10% for an incandescent bulb.