Denticollis linearis (Linnaeus, 1758)

Occurs throughout England and Wales with scattered records across Scotland except from the far north. Common throughout Watford in a range of habitats; parkland, mixed woodland and scrub/moorland (Croxley Common). Adults appear in early June, being found by sweeping long, dry grass or beating low shrubs and trees on woodland margins and parkland. They soon become adventitious having been found on July mornings in Watford town centre (outside the market where there are a very powerful series of MV lamps.) The omniverous larvae feed on insect larvae as well as live wood beneath the bark, generally in deciduous wood but also recorded from pine. The species also develops on moorland, larvae being active in shallow peat or moss (Alexander). Pupation takes place in the spring.

9-13mm. Unique among the Elaterids in having very prominent eyes but see Ctenicera cuprea Fab. where they are moderately so. This character, along with the produced pronotal hind angles will identify the insect. Females have shorter antennae and their elytra are somewhat dilated behind the middle when compared with males. Joy describes colour differences but these have proved unreliable unless very distinctive forms are found i.e. Female with elytra black with yellow borders or male entirely yellow with head mostly black.

Description from 4 Watford specimens at X20