Purse-case
Guides
Hydroptilidae
Microcaddisflies, Purse-case Caddisflies
Hydroptilidae is the largest family of caddisflies (Trichoptera), comprising over 2,600 species in 76 genera and six subfamilies. Adults are minute, rarely exceeding 5 mm in length, making them the smallest caddisflies. They are characterized by simple hypermetamorphosis in larvae: early instars (I–IV) are caseless and free-living, while the final instar (V) constructs a distinctive purse-shaped portable case and develops a greatly enlarged (physogastric) abdomen as the primary feeding and growing stage. The family has a worldwide distribution, with subfamilies showing distinct regional patterns. Adults are strongly attracted to ultraviolet lights and may congregate in large numbers.