Insects of Britain and Ireland: the genera of Lepidoptera-Geometridae

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L. Watson and M. J. Dallwitz

Chesias Treitschke


Adults. Diurnal, crepuscular, and nocturnal. Antennae of males simple; simply-ciliate.

Wingspan 34–38 mm. Forewings relatively narrow-elongate. The outer margin of the forewing convexly curved. Forewings rather dark brown or light fuscous; without a clear discal mark. Hindwings plain; grey or brownish grey, sometimes terminally darker; with a clear discal mark, or without a clear discal mark; faintly transversely lined (C. rufata), or without transverse lines.

Vein 10 of the forewings arising independently of 9; arising independently, anastomosing with 11 and 9 to form a double areole. Hindwings exhibiting a tubular vein 5. Vein 5 of the hindwings arising from about the middle of the transverse vein, or arising from below the middle of the transverse vein (?). Vein 8 of the hindwings approximated to or anastomosed with the upper margin of the cell to the middle or beyond. Hindwing veins 6 and 7 stalked.

Posterior tibiae of males 4-spurred.

Early stages. Larvae feeding on Cytissus.

British representation. 3 species; South-east England, Central-southern England, South-west England, English Midlands, Northern England, Southern Scotland, Northern Scotland, Wales, and Ireland. Living adults found September and October. C. legatella (The Streak), C. rufata (Broom-tip).

Subfamily. Larentiinae.

General comments. The forewings relatively elongate, the front tibiae with a horny apical hook.

Illustrations. • C. legatella (The Streak) and C. rufata (The Broom-tip), with Acasis, Aplocera, Asthena, Carsia, Discoloxia, Euchoeca, Hydrelia, Lithostege, Lobophora, Minoa, Odezia, Pterapherapteryx, Trichopteryx: Newman 1869. • C. legatella and C. rufata, with other Larentiinae: Kirby 49.

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. Insects of Britain and Ireland: the genera of Lepidoptera-Geometridae. Version: 8th June 2016.’.