Trechus quadristriatus (Schrank, 1781)

Very widely distributed and generally common throughout England and Wales including the Isle of Wight, Scilly, Lundy, Angelsey, and Man although records from the western half of the country and Wales are more scattered and much less frequent. In contrast to the west, the east coast is more or less continuously recorded from Sussex to Angus in Scotland. But for the southeast, Scottish records are few and scattered but the species occurs to the northernmost parts including the Western Isles, Orkney and Shetland. Generally a species of open and dry habitats including agricultural land but also in urban or built up areas; parks, gardens etc. Common throughout our Watford area; we have recorded them, often inlarge numbers and usually in company with Bradycellus verbasci, at light in several town centre gardens and in Casiobury park. During July and August they are common under the sodium lights along the Radlett road open space. We have not recorded them from pitfall traps or from extractions from a wide variety of habitats nor from any diurnal recording. The species is an autumn breeder and at this time large swarms are sometimes recorded in the east of England (Luff, 1998), we recorded something approaching this during the mid 1980's when many hundreds of specimens occured at light (filament bulbs) in a domestic garden at Eastcote in Middx.

3.5-4.1mm A broad and flat species with weakly rounded and somewhat parallel elytra, pale brown with head and sometimes the pronotal disc darker. Head shiny black with indistinct isodiametric microsculpture (X40), eyes convex and protruding, frontal furrows converging to between the eyes then diverging semicircularly behind eyes and through temples. Two punctures beside eyes, the anterior very close; within its own diameter to the inner margin of the eye. Terminal segment of maxillary palps long and pointed, as long as penultimate. Antennae and palps testaceous. Pronotum smooth and shiny, transverse (around 5:8) with sides rounded to distinct (or at least evident) hind angles. Basal margin flat medially, oblique laterally. Elytra pale brown or lighter laterally and at shoulders, irridescent with very fine microsculpture which is just visible at X40. Lateral margin produced over humeri but not reaching scutellum. Striae become fine laterally; normally with four well developed and finely punctate striae from suture then one or two very fine and interrupted striae lateral to these. Sutural striae recurved then deeply impressed before apex. Third interstice with three setiferous punctures, these can be very difficult to see and sometimes it is easier to manipulate a specimen under strong light and look for the setae, the posterior of these is often at the apex of the third striae but always lies within the area bordered by the recurved sutural striae. Wings full (diagnostic), these are often visible through the elytra. Legs entirely testaceous. Front tibiae with a strong subapical notch and a single long spur inside at apex. Male with two dilated protarsal segments.

Description from 4 Watford specimens at X40