Eulagius filicornis (Reitter, 1887)
Native to North Africa and southern France, this species has spread north into Europe over recent decades and has become established at many sites; the first European record beyond the species natural range was from England in 1993, it was first recorded from Spain in 2007 and from Belgium in 2008 and is now known from many sites in central Europe. Since the first UK record from Berkshire the species is now known from many widely scattered records across the south of England and it is now probably locally common throughout the area e.g. we find it regularly in our local woodland and parks in south Hertfordshire. Adults usually occur under bark or in wood in the vicinity of the fungus Stereum hirsutum (Willd.) Pers. (1800) in which the larvae are presumed to feed, often on oak but also other deciduous trees; we have found then on beech and hawthorn trunks and in extractions of debris from beneath oak bark. Adults are nocturnal and may be seen running on bark or wedged between bark crevices, they usually occur in numbers and often along with other mycetophagids.
This species is quite distinctive among our fauna due to the characteristic elytral markings. 3.3-3.9mm. Elongate and rather parallel-sided, head and pronotum brown with various diffuse darker areas, elytra pale yellowish-brown with the area around the scutellum and a large U-shaped marking around the disc dark brown or black, legs pale brown and antennae dark brown with the base and the tip of the terminal segment paler, entire dorsal surface finely punctured and pubescent. Head transverse; smoothly convex with protruding and asymmetric eyes, antennae filiform with all segments elongate. Pronotum transverse, broadest near the base and smoothly curved to a straight apical margin, the anterior angles hardly visible from above, basal margin sinuate and finely bordered laterally, surface smoothly convex and without basal fovea. Scutellum widely transverse, sinuate laterally and weakly curved across the broadly truncate apical margin. Elytra with rounded shoulders, straight laterally and continuously curved apically, finely and randomly punctured throughout and lacking striae. Legs long and slender, the tibiae only slightly broadened beyond the base and with tiny apical spurs. Tarsi 4-segmented in the female, 3,4,4 in the male, basal segment of front and middle tarsi about as long as the terminal segment, basal segment of hind tarsi longer than the terminal segment. Claws smooth and without a basal tooth.