Worldwide over 6000 species of Caddis Flies have been described. In Holland some 177 species of caddisfly exist. In Britain some 190 and in Belgium well over 200 species have been found. Best known are the larvae which live in water and build cases around them. The produce a kind of silk to which they stick whatever they find in the water. These cases differ with each species, even though closely related species make more or less the same case. The cases sometimes are apparently randomly made of whatever the animal was able to find, rather like some of the cases used by the bagworm moths, or the way the larvae of Green Lacewings camouflage themselves. Others are meticulously constructed of twigs, pebbles or shells of the same size and colour. Other species build a case on a flat stone. The silk is sometimes also used to build a net to catch prey. While some species are carnvivores, most will eat almost anything. The adults are all brown, dull looking animals. The wings are big and hairy and folded like a roof over the body. They are not among the best of flyers, yet often found far from water. They are easily attracted by light. Some of them will eat some nectar, but most imagines don't eat at all. The antennae are often very long, thin and wire like.
Most species are just brown. They are hard to identify. Besides, good (field)guides are lacking. In most general fieldguides beautiful pictures of the larvae and their constructions are presented, but there is baffling little on the adult flies. Molanna angustata is one of those brown species. There are no markings, apart from a slightly lighter smear near the loweredge of the wing.