Nalassus Laevioctostriatus (Goeze, 1777)

Widely distributed throughout England and Scotland although scarce in the north. Can be common where found; under loose bark, logs or in rotten wood, often in groups or many individuals over a few metres of suitable habitat. In woodland but also around isolated dead wood on moors. On heathland at the base of heather and under debris on exposed cliffs and high ground. Active at night when it can be found grazing on Pleurococcus algae on tree trunks. In the absence of trees they feed on lichen thus obtaining the associated algae.
By no means common around Watford, we can only qualify this by saying that over the last few years (2004-7) we have examined a huge amount of bark by day and night. Found occasionally in Whippendell wood during the summer; once at M.V. (2006) and once on Betula at night (2007). During March 2007 we found a large colony (around 50 specimens) under dead Oak bark in Scots wood, all were dead and hosting to varying degrees a soft white felt like fungus, and all were assembled around a funnel spider's web, the spider being present. It seemed obvious at a glance that the spider had spent the winter feeding on them.

6.5-12mm, width 3-5mm. Dark reddish brown to almost black, usually with a weak metallic reflection. Entire upper surface punctate and shining, without pubescence. Reminiscent of carabidae but count the tarsal segments (5-5-4). Head evenly rounded in front of eyes above antennal insertion, fronto-clypeal margin not emarginate. Antennae long, reaching back beyond base of pronotum, third segment at least twice the length of the second. Pronotum completely bordered, evenly rounded from front to hind angles, front angles weakly projecting. Elytra with 8 weakly punctate striae. Basal segment of hind tarsi shorter than 2-4 together, all tarsi light red with two strong claws. Basal segments of pro and meso tarsi dilated and pilose below in male, simple in female.

Description from 2 Watford specimens at X20