Insects of Britain and Ireland: the families of Lepidoptera
Adults nocturnal; relatively medium-bodied; medium built (wingspan more than 8 and less than 15 times the thoracic width) to heavily built (wingspan less than 8 times the thoracic width); wings in repose packed with the forewings directed backwards to cover hindwings and abdomen.
Antennae very short to of medium length; extending to about 0.45–0.55 times the length of the forewing. Antennae of males dentate, or simple (then filiform); non-ciliate (when filiform), or simply-ciliate. Ocelli absent. Chaetosemata absent. Maxillary palps well developed, or much reduced, or absent; 1 segmented, or 3 segmented. Labial palps porrect; 3 segmented. Proboscis absent.
Wingspan 16–32 mm; 7–10.6 times the thoracic width. Forewings broad; 1.6–2.1 times as long as wide. The outer and hind margins angled at 100–105 degrees. The outer margin convexly curved; forewings apically blunt. Hindwings broadly rounded; similar in breadth to the forewings; with a rounded apex; the upper surfaces plain; with neither discal spot nor transverse lines; with a frenulum.
Neuration of forewings and hindwings dissimilar. Forewings 13 veined; with 2 anal veins. The anal veins of the forewings comprising 1b and 1c. Forewings exhibiting a tubular vein 1c. Vein 1b of the forewings furcate proximally. The transverse vein complete. Discal cell of the forewings containing a tubular media (M) vein (likewise that of the hind-wings). Hindwings 10 veined; with 3 anal veins. The anal veins of the hindwings comprising 1a, 1b and 1c. Hindwings exhibiting vein 1a; exhibiting a tubular vein 1c. Vein 1b of the hindwings simple. The transverse vein complete. The hindwing cell emitting more than six veins, or emitting no more than six veins. 7 veins arising from the hindwing cell (including the anastomosed vein 8). The cell-derived hindwing veins 6+7 proximally joined (connate). Vein 8 of the hindwings joined to the cell only by a bar (Heterogenea), or anastomosing with the upper margin of the cell (Apoda); not approximating to vein 7.
Fore-legs without a tibial epiphysis. Tibiae of middle legs without spurs (rarely), or 2-spurred. Posterior tibiae without spurs, or 2-spurred, or 4-spurred.
Tympanal organs absent.
Eggs, larvae and pupae. Eggs markedly flattened (scale-like); smooth or minutely pitted. Larval prolegs 0 (lacking altogether). Larvae with urticating hairs, or without urticating hairs; exposed feeders. On Quercus, Fagus and Populus.
Pupae concealed; above the ground (in a cocoon attached to a leaf). Empty pupae protruded from place of concealment.
British representation. Genera 2; 2 species. Apoda limacodes (Festoon), Heterogena asella (The Triangle).
Classification. Macromoths. Suborder Ditrysia. Superfamily Zygaenoidea.
Illustrations. • Apoda limacodes (Festoon: Newman). • Apoda limacodes (Festoon: Kirby). • Apoda limacodes, neuration. • Heterogenea asella (Triangle): Stephens II, 1830. • Sterrhopteryx fusca (male and apterous female): Stephens II, 1830.
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Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. Insects of Britain and Ireland: the families of Lepidoptera. Version: 16th May 2016. delta-intkey.com’.