Japanese Alderfly vs Hellgrammite

Side-by-side species comparison

Attribute Japanese Alderfly Hellgrammite
Scientific Name Sialis japonica Nigronia serricornis
Order Megaloptera Megaloptera
Family Sialidae Corydalidae
Size 15-25 mm wingspan 40-60 mm wingspan
Habitat Rivers & Streams Rivers & Streams
Diet Predators Predators
Regions Japan, East Asia Eastern North America
Conservation Least Concern Least Concern

Japanese Alderfly

A medium-sized alderfly found in ponds and slow streams across Japan. It is one of the most common megalopterans in East Asian lowland waters.

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Did You Know?

It is one of the few megalopterans adapted to living in rice paddy fields.

Hellgrammite

A dark-colored dobsonfly whose larvae, known as hellgrammites, are prized as fishing bait. Adults are smaller than Corydalus and have serrated antennae.

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Did You Know?

Hellgrammite larvae are so effective as fishing bait that they are commercially collected and sold to anglers.