Fever Fly vs Caterpillar Tachinid

Side-by-side species comparison

Attribute Fever Fly Caterpillar Tachinid
Scientific Name Dilophus febrilis Lydella thompsoni
Order Diptera Diptera
Family Bibionidae Tachinidae
Size 5-7 mm 5-8 mm
Habitat Farmland Farmland
Diet Nectar Feeders Parasites
Regions Europe, Asia Europe, North America
Conservation Least Concern Least Concern

Fever Fly

A small, shiny black march fly with spiny front tibiae used for digging. It was once believed to cause fevers in humans, hence its common name, though it is completely harmless.

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Did You Know?

Its spiny front legs are used by females to dig into soil for egg-laying, an unusual adaptation among flies.

Caterpillar Tachinid

A small gray parasitic fly that attacks European corn borer larvae. It was introduced to North America as a biological control agent.

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Did You Know?

Females deposit live larvae rather than eggs directly onto the host caterpillar.