Yellow Swarming Fly vs Viennese Ground Beetle

Side-by-side species comparison

Attribute Yellow Swarming Fly Viennese Ground Beetle
Scientific Name Thaumatomyia notata Carabus fabricii
Order Diptera Coleoptera
Family Chloropidae Carabidae
Size 2-2.5 mm 22-30 mm
Habitat Grasslands Forests
Diet Predators Predators
Regions Europe Eastern Alps, Carpathians
Conservation Least Concern Least Concern

Yellow Swarming Fly

A tiny yellow fly famous for forming enormous hibernation aggregations in buildings, sometimes numbering millions. Larvae are predatory on root aphids in grassland.

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Did You Know?

Can form hibernation clusters of millions in attic spaces, with individual aggregations weighing several kilograms.

Viennese Ground Beetle

A large metallic ground beetle of mountain forests and alpine meadows. It is a powerful predator of earthworms and snails.

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Did You Know?

It can spray a pungent defensive fluid from glands near its abdomen.