The Hydroptilidae are a large family of caddisflies (Trichoptera) with a worldwide distribution.

Their larvae do not build a protective case until the final instar of their growth.

At that time however, they build a typically Purse-shaped case, either portable or stuck to the substrate, in which the larva finishes growth and pupates.

They are traditionally placed in the suborder Spicipalpia, which do not seem to be a natural monophyletic group, but rather an evolutionary grade of moderately advanced caddisflies.

[1] More often, the Hydroptilidae are placed in a monotypic superfamily Hydroptiloidea, either in the Spicipalpia or – probably more appropriately considering the present state of caddisfly phylogeny – incertae sedis in the Trichoptera.