British Insects: Pug moths (Lepidoptera-Geometridae)
Adults. Thorax with a white posterior spot. Posterior tibiae of males 4-spurred. Wingspan 21–23 mm. Forewings distinctly elongate to not noticeably elongate; the outer margin convexly curved; the costa more or less straight to arched; apically somewhat pointed.
Forewings relatively conspicuously patterned to dingy; whitish-grey, conspicuously striped by markedly angulated dark grey striae and light-and-dark fasciae, veins marked briefly blackish on the edges of the postmedian fascia, the the subterminal line inconspicuous and incomplete towards the tornus; or largely unpatterned in melanic forms. The forewing patterning more or less confined to the dark discal spot (f. nigra), or not restricted to dark discal or costal and discal spots. Forewings with a dark discal mark. The discal mark dot-like; not whitish-edged; black and distinct. Forewings without a tornal spot. Forewing fringes somewhat chequered.
Hindwings whitish grey in the typical form, dark in others; less conspicuously patterned than the forewings, or patterned similarly to the forewings (in melanics); conspicuously patterned, or rather plain; quite conspicuously dorsally and postmedianly transversely striated, or without transverse striation (i.e., unpatterned in some forms); with a clear discal mark; the fringes conspicuously chequered to not conspicuously chequered.
The abdomen conspicuously patterned; neither ringed nor banded nor white-based; with lateral series of black spots.
Neuration. Forewing and hindwing neuration layout revealed in detail by conspicuous darkening (including the outlines of the cells, in f. nigra), or not conspicuously darkened.
Genitalia. The male abdominal plate in the form of a single sclerotized patch with retuse apex. The bursa copulatrix ornamented over most of its surface; densely scobinate, without spines.
Early stages, ecology. Botanically specialised. Foodplants Gymnospermous; Pinaceae. The larvae found on Larix europea and other larches, and in captivity Picea abies; feeding on leafy shoots (on the needles).
Months of appearance, distribution. Adults abroad May to September; larvae found late June to September. South-east England, Central-southern England, South-west England, English Midlands, Northern England, Southern Scotland, Northern Scotland, Wales, and Ireland (locally common throughout, except Orkney).
Melanism. Melanic imagines frequent. Melanics of E. tripunctaria, E. trisignaria, E. subfuscata, E. virgaureata and E. lariceata are not reliably separable without resort to the genitalia. Dark forms with all markings obsolete except the discal spots (e.g., the widespread E. lariceata f. nigra) are frequent.
Special key characters. Forewings not dominated by double ante- and postmedian lines. The subterminal line not whitish throughout. Hindwings whitish, or fuscous, or pale grey.
General comments. Typical adults similar to E. subfuscata, but differing in the somewhat more elongated forewings with lighter ground colour and no reddish tinge, the darker and more angulated striae and black-marked veins, the larger discal spot, and the somewhat longer cilia of the male antennae.
Illustrations. • E. lariceata (Larch Pug), with larva: Barrett. • E. lariceata, E. subfuscata, E. tripunctaria and E. pimpinellata, with larvae: Barrett. • E. lariceata (Larch Pug), with other pugs: South. • E. lariceata(?), with 9 other pugs illustrated by Hubner (1790–1817). • E. lariciata (Larch Pug), with other Pugs: Swain (5).
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: Pug moths (Lepidoptera-Geometridae). Version: 29th December 2011. http://delta-intkey.com’.