| | Insects of Britain and Ireland: the families of Trichoptera (caddis flies) |
Including Goeridae.
Adults. Antennae about as long as the fore-wings (to only slightly shorter); stout; with an elongated first segment (usually), or with a short first segment. Ocelli absent. Maxillary palps usually very pubescent or pilose, (1–)2–3 segmented (in the males, where they vary in form but are always upturned in front of the face), or 5 segmented (in females, in which unlike those ot the males they are conventional in form). The maxillary palps of males (1–)2–3 segmented. Maxillary palps filiform, with cylindrical segments, or thick; the terminal segment inflexible, not multi-articulated, not annulated, and not much elongated (at least in the female). The scutellum exhibiting a large median wart (Goerinae), or exhibiting a pair of warts.
The fore-wings (6–)8–15 mm long; with a discoidal cell; apical forks 2 (male Lepidostoma, with only 1 and 3), or 4 (commonly, with 1, 2, 3 and 5), or 5 (female Brachycentrus with 4 as well). The hind-wings similar in width to the fore-wings; with a discoidal cell, or without a discoidal cell; apical forks 1 (only fork no. 1 in Lepidostoma), or 2 (1 and 5, in male Brachycentrus), or 3 (commonly, with 1, 2 and 5), or 4 (Goera and female Brachycentrus with 1, 2, 3 and 5).
Front tibia 2 spurred. Middle tibia 2 spurred, or 4 spurred (Goerinae). Hind tibia 3 spurred (Brachycentrus), or 4 spurred.
Larvae. The larvae constructing and living in transportable cases (the cases of sand or stones); eruciform. The mesonotum sclerotized; entire, or divided longitudinally into two sclerites, or divided into four sclerites, or divided into eight sclerites (Silo). The metanotum sclerotized, or entirely membranous; when sclerotized, divided into four sclerites, or divided into six sclerites. The metasternum with no more than a median pair of bristles. Abdominal segment 1 with retractable papillae; 8 with a lateral comb of fine spicules (these sometimes very pale). The larva with the terminal abdominal prolegs fused basally, forming an ostensible tenth segment.
Comments. The larvae of Goera and Silo are parasitized by the ichneumonid, Agriotypus armatus Curtis.
British representation. 10 species. Genera: Brachycentrus, Crunoecia, Goera, Lasiocephala, Lepidostoma, Notidobia, Sericostoma, Silo.
Illustrations. • Crunoecia irrorata Curtis (Many-spotted Caddis-fly: B. Ent. 544). • Species type description: Crunoecia irrorata (B. Ent. 544, legend+text). • Crunoecia irrorata (B. Ent. 544, text cont.). • Sericostoma personatum var. analis: Stephens VI, 1835 (as Potomaria analis). • Sericostoma spencii (probably = S. personatum), and palps: Stephens VI, 1835. • Goera, Lasiocephala, Lepidostoma, Notidobia and Sericostoma: wings and palps. 1, Sericostoma personatum, fore- and hind-wings of male. 2a and 2b, Notidobia ciliaris, male: fore- and hind-wings, and palps (labial drooping, maxillary ascending). 3a and 3b, Goera pilosa: wings and maxillary palp of male. 4a-4c, Lepidostoma hirtum: wings (4a) and head (4b) of male, the latter showing the base of an antenna, a labial palp (drooping) and a modified, ascending maxillary palp; and wings of the female (4c). 5a-5d, Lasiocephala basalis: wings (5a), base of antenna (5b), and palps (5c, maxillary above) of male; and wings of female (5d). Apical forks of wing veins numbered. From Mosely (1939). • Wings of assorted Trichoptera. Trichopteran wings. PHRYGANEIDAE: 1, female Oligotricha clathrata (fore-wing); 2, female Phryganea grandis (fore-wing); 3, female Phryganea striata (fore-wing); 4, female Phryganea varia (fore-wing). LIMNEPHILIDAE: 5, male Glyphotaelius pellucidus (fore-wing); 6, female Glyphotaelius pellucidus (fore-wing); 7, Rhadicoleptus alpestris (fore-wing); 8, Potamophylax latipennis (fore-wing); 9, Halesus digitatus (fore-wing); 10, Chaeropteryx villosa (fore-wing). SERICOSOMATIDAE: 11, male Lepidostoma hirtum ( hind-wing); 12, male Silo nigricornis (hind-wing). LEPTOCERIDAE: 13, Mystacides longicornis (fore-wing). HYDROPSYCHIDAE: 14, Hydropsyche instabilis (fore-wing). POLYCENTROPIDAE: 15, Plectronemia conspersa (fore-wing). PHILOPOTAMIDAE: 16, Philopotamus montanus (fore-wing). RHYACOPHILIDAE: Rhyacophila dorsalis (fore-wing). From Mosely (1939, with approximate wing lengths added). • Brachycentrus, Lepidostoma and Silo: larvae and cases. 1a, Brachycentrus subnubilis larva, and 1b the case from which it has been removed. 2, Lepidostoma hirtum, larva in its case. 3, Silo pallipes: 3a, pro-, meso- and metanota and (lowermost) the first abdominal segment); 3b, the larval case. From Hickin (1952).
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, 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. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. Insects of Britain and Ireland: the families of Trichoptera (caddis flies). Version: 27th July 2019. delta-intkey.com’.
