Owlflies look like dragonflies outfitted with butterfly heads. Dragonfly shaped and sized, they have long, clubbed antennae and large, bulging eyes. Some rest with their abdomens angled away from the perch, making their bodies look like twigs.
You can distinguish the two genera in North America by looking at the eyes: Those in genus Ululodes have a groove or crease in each eye; those in genus Ascaloptynx lack the groove. Then, if you’ve found the latter, you know the species, too, since there’s only one owlfly in that genus in North America, A. appendiculata, a beautiful insect with gold highlights.
The larvae are flattened, oval, segmented, gray, brown, or black insects with a distinct head and a pair of caliper-like mandibles that are usually held wide open. They look a lot like antlion larvae but their bodies have a fringe of tiny finlike extensions along the two sides. Some species glue detritus to their backs for camouflage.