The triangle (Heterogenea asella) is a species of moth of the family Limacodidae.

It is found in most of the Palearctic realm.

[2] Adults are on wing from the end of May to mid July in one generation per year.

The larvae feed on Acer, Corylus, Fagus and Quercus species.

This article about a taxon in the moth family Limacodidae is a stub.