British Insects: the families of Caddis flies (Trichoptera)


L. Watson and M. J. Dallwitz

Hydroptilidae Stephens

Adults. Adults minute. Antennae much shorter than the fore-wings to about as long as the fore-wings (shorter in females than in males); stout; with a short first segment. Ocelli present, or absent (varying from genus to genus). Maxillary palps 5 segmented; filiform, with cylindrical segments; the terminal segment inflexible, not multi-articulated, not annulated, and not much elongated. The mesoscutum without warts. The scutellum without conspicuous warts.

The fringes of the wings longer than the maximum width of the hind-wings (the wings relatively long and slender, generally with acute apices). The fore-wings (1.5–)2.5–4(–4.5) mm long; without a discoidal cell; apical forks 0–3 (? - the neuration often being hard to interpret), or 3 (with Agraylea and Allotrichia exhibiting forks 1, 2, and 3). The hind-wings narrower than the fore-wings; without a discoidal cell; apical forks 0–3 (? - the neuration usually hard to interpret), or 3 (Allotrichia having forks 2, 3 and 5), or 4 (Agraylea with forks 1, 2, 3 and 5).

Front tibia 0 spurred. Middle tibia 2 spurred, or 3 spurred. Hind tibia 4 spurred.

Larvae. The larvae constructing and living in transportable cases (in the last instar only, making a silken, transportable case sometimes with sand or plant fragments attached), or case-less and free swimming (in the first four instars). The larval case very small, and seed- or flask-shaped. The larvae campodeoid. The mesonotum sclerotized. The metanotum sclerotized; divided longitudinally into two sclerites. Abdominal segment 1 without retractable papillae. The larva with the terminal abdominal prolegs free of one another.

British representation. 29 species. Genera: Agraylea, Allotrichia, Hydroptila, Ithytrichia, Orthotrichia, Oxyethira, Oxytrichia, Tricholeiochiton.

Illustrations. • Orthotrichia angustella imago and Hydroptila maclachlani larva.

To view the illustrations with detailed captions, go to the interactive key. This also offers full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. British insects: the families of Caddis flies (Trichoptera). Version: 29th December 2011.’.