Insects of Britain and Ireland: the families of Coleoptera

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L. Watson and M. J. Dallwitz

(Variant) Drilidae (males)

General appearance. Body (of males) not noticeably widest either behind the thorax, or at the rear.

Detailed morphology. Labrum mostly moderately to heavily sclerotized. Antennae about half the insect's head to tail length (males); pectinate (males).

The pronotum with lateral keels (pronotal carinae). Scutellum conspicuous; posteriorly narrowly rounded or acute. The prosternal process present; complete, or incomplete; falling short of the mesoventrite. The fore-leg coxae countersunk in ‘procoxal cavities’. The fore-leg coxal cavities open behind externally; broadly open; strongly transverse; without lateral extensions; internally open. The mid-leg coxae countersunk in ‘mesocoxal cavities’; separated by in males, less than the shortest diameter of the cavity. The mid-leg coxal cavities in males, contiguous, or narrowly separated; not or scarcely oblique; open laterally. Hind-leg coxae contiguous or narrowly separated; extending laterally to meet the elytra. Tarsal segmentation formula 5, 5, 5. The tarsi exhibiting bilobed segments. The penultimate segment not distinctly shorter than the antepenultimate one.

Elytra present (males); elytra (of males) covering most to all of the abdomen. Elytra apunctate, irregularly punctate, or each with fewer than 6 longitudinal lines of punctures or impressed striae. Wings well developed (males). Abdominal sternites 6–7 (males); all articulated and moveable. The male external genitalia trilobate.

Adult habitat, ecology. Land-dwellers; predacious (on gastropods).

Illustrations. • Drilus flavescens, male and female (with unrelated taxa): Fowler 4, 116 (1890). • Fowler 4, 116 (1890): original legend.. • Drilus flavescens (Rye & Fowler).

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 families of Coleoptera. Version: 16th May 2016.’.