Most species have at least partially metallic, patterned coloration and are diurnal, sometimes swarming around the tips of branches with an undulating flight.

About 50 species occur in Europe, of which most widely noted is the green longhorn (Adela reaumurella) which can sometimes reach great abundance; due to climate change[2] its peak flying season is shifting towards spring.

In general, they are more plentiful in the Northern Hemisphere, but the family occurs in the Neotropics, sub-Saharan Africa, South-East Asia and Australia too.

[3] Adelidae appear in certain plants, in which the females insert their eggs or just lay among leaf litter, and the caterpillars make a case, completing their development on the ground.

But like other Heteroneura, they already possess the apomorphic sucking proboscis – usually considered a defining feature of Lepidoptera, but the most ancestral moths still live on solid food which they chew.