Large Alderfly vs Large Oak Cynipid

Side-by-side species comparison

Attribute Large Alderfly Large Oak Cynipid
Scientific Name Sialis nigripes Cynips quercusfolii
Order Megaloptera Hymenoptera
Family Sialidae Cynipidae
Size 15-20 mm 2.5–4 mm
Habitat Rivers & Streams Woodlands
Diet Herbivores Herbivores
Regions North America Europe
Conservation Least Concern Not Evaluated

Large Alderfly

A relatively large alderfly with dark wings and black legs found near rivers in eastern North America. Adults rest on streamside vegetation during the day.

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Did You Know?

Alderfly larvae breathe through feathery gills along their abdomen and a single long tail filament that acts as an additional gill.

Large Oak Cynipid

A gall wasp that induces cherry-sized galls on the undersides of oak leaves. The galls turn from green to red as they mature in autumn.

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Did You Know?

The colorful galls were historically known as 'oak cherries' and were sometimes mistaken for real fruit by children.