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Insects of Britain and Ireland: the families of caddis flies (Trichoptera)

L. Watson and M.J. Dallwitz

Conventional key

If you are serious about identification, you should use the interactive key. It is far superior, with flexible choice of characters, character notes and illustrations, error tolerance, full taxon descriptions, and taxon illustrations.

1(0).
  • Ocelli present ... 2
  • Ocelli absent... 7

2(1).
  • Front tibia 0 spurred ... 3
  • Front tibia 1 spurred... 4
  • Front tibia 2 spurred... 5
  • Front tibia 3 spurred... Rhyacophilidae Stephens

3(2).
  • The fore-wings with a closed discoidal cell; adultfore-wings more than 4 mm long; the scutellum exhibiting a pair of warts; the fringes of the wings shorter than the maximum width of the hind-wings; the hind-wings wider than the fore-wings ... Limnephilidae Kol.
  • The fore-wings without a closed discoidal cell; adult fore-wings up to 4 mm long; the scutellum without conspicuous warts; the fringes of the wings longer than the maximum width of the hind-wings;the hind-wings narrower than the fore-wings... Hydroptilidae Stephens

4(2).
  • The hind-wings similar in width to the fore-wings;the maxillary palps of males 5 segmented; apical forks in the fore-wings 5; the larvae campodeoid; the mesonotum of the larva entirely membranous ... Philopotamidae Wallengr.
  • The hind-wings wider than the fore-wings; the maxillary palps of males 1 to 3 segmented; apical forks in the fore-wings 4; the larvae eruciform; the mesonotum of the larva sclerotized at least to some extent... Limnephilidae Kol.

5(2).
  • The maxillary palps of males 4 segmented; the larvae eruciform ... Phryganeidae Burm.
  • The maxillary palps of males 5 segmented; the larvae campodeoid... 6

6(5).
  • The larvae constructing and living in transportable cases ... Glossosomatidae Ulmer
  • The larvae constructing fixed, silken tubes... Philopotamidae Wallengr.
  • The larvae case-less and free swimming... Philopotamidae Wallengr.

7(1).
  • The fore-wings with a closed discoidal cell ... 8
  • The fore-wings without a closed discoidal cell... 14

8(7).
  • Middle tibia 2 spurred ... 9
  • Middle tibia 4 spurred... 11

9(8).
  • The maxillary palps of males 1 to 3 segmented ... Sericostomatidae McLach.
  • The maxillary palps of males 5 segmented... 10

10(9).
  • The hind-wings with a closed discoidal cell; hind tibia 4 spurred; apical forks in the fore-wings 5; apical forks exhibited by the hind-wings 4; the larvae constructing fixed retreats of stones and vegetable dèbris ... Hydropsychidae Curtis
  • The hind-wings without a closed discoidal cell; hind tibia up to 3 spurred; apical forks in the fore-wings 2 to 3; apical forks exhibited by the hind-wings 1 to 3; the larvae constructing and living in transportable cases... Leptoceridae Leach

11(8).
  • The hind-wings narrower than the fore-wings ... Psychomyiidae Kol.
  • The hind-wings similar in width to the fore-wings... 12
  • The hind-wings wider than the fore-wings... Odontoceridae (Wallengr.) Ulmer

12(11).
  • Front tibia 2 spurred; the larvae constructingand living in transportable cases; the larvae eruciform; the mesonotum of the larva sclerotized at least to some extent ... 13
  • Front tibia 3 spurred; the larvae case-less and free swimming; the larvae campodeoid; the mesonotum of the larva entirely membranous... Polycentropidae Ulmer

13(12).
  • The maxillary palps of males 1 to 3 segmented;the larval case not made of sand grains and curved, the hind extremity not covered by a dark membrane with a central slit ... Sericostomatidae McLach.
  • The maxillary palps of males 5 segmented; the larval case made of sand grains and slightly curved, the hind extremity covered by a dark membrane with a central slit... Odontoceridae (Wallengr.) Ulmer

14(7).
  • The fringes of the wings longer than the maximumwidth of the hind-wings; front tibia 0 spurred; the larvae campodeoid; the metanotum of the larva sclerotized ... Hydroptilidae Stephens
  • The fringes of the wings shorter than the maximum width of the hind-wings; front tibia 2 spurred; the larvae eruciform; the metanotum of the larva entirely membranous... 15

15(14).
  • Middle tibia 2 spurred; the larval case not ofsand grains and shield-shaped with wing-like extensions ... Beraeidae Wallengr.
  • Middle tibia 4 spurred; the larval case shield-shaped, and made of sand grains, with wing-like lateral extensions... Molannidae Wallengr.

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’.

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