Ichneumon Wasp vs Large Square-headed Wasp

Side-by-side species comparison

Attribute Ichneumon Wasp Large Square-headed Wasp
Scientific Name Megarhyssa macrurus Ectemnius cephalotes
Order Hymenoptera Hymenoptera
Family Ichneumonidae Crabronidae
Size 25-50 mm body plus 100+ mm ovipositor 12-18 mm
Habitat Woodlands Woodlands
Diet Parasitoids Wood Feeders
Regions North America Europe
Conservation Least Concern Least Concern

Ichneumon Wasp

A large parasitoid wasp with an extremely long, thread-like ovipositor that can exceed the length of its body. Females drill through solid wood to reach their host larvae deep inside.

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Did You Know?

The female can somehow detect horntail larvae vibrations through several centimeters of solid wood and then drill her flexible ovipositor to reach them with remarkable accuracy.

Large Square-headed Wasp

A large solitary wasp that nests in dead wood and provisions its nest with captured flies. Has a distinctively large, square-shaped head. Common in gardens and woodland.

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Did You Know?

Nests in old beetle holes in dead wood, stocking each cell with paralyzed flies for its developing larvae.