Trox scaber (Linnaeus, 1767)
This is the most frequently recorded of our Trox species, occurring locally throughout southern and central England and Wales and sporadically north to southern Scotland. Adults and larvae occur in bird nests, especially those in hollow trees e.g. owl nests that contain pellets and animal detritus. Adults may be attracted to light, carrion or old bones.
5-8mm. A long-oval and very convex species; entirely black or dark brown except for the antennae, and sometimes the anterior pronotal margin, which are pale to dark red. Head transverse; shiny, weakly microsculptured and covered with wide and shallow punctures. Eyes visible from above, outside a weakly expanded canthus. Margins with long and pale setae. Antennae inserted on the side margin in front of the eyes; the 2 basal segments broadly expanded and with long, pale setae, 3-7 small and 8-10 forming a wide and finely pubescent club. Pronotum transverse; laterally explanate and fringed with broad, pale scales. Broadest behind the middle, front angles strongly protruding and hind margin sinuate. Surface punctation as on the head, disc with 3 pairs of depressions; the 2 median ones may form a longitudinal channel. Sides of the scutellum curved, central part raised. Elytra very convex; the apex not visible from above. Sutural stria narrower than adjacent interstices. Lateral margin bordered to the apex and fringed with short, pale scales. Interstices 1, 3 and 5 with small but strongly raised tubercles, those on the remaining interstices much smaller, all covered with short, raised scale-like pubescence. Between these are 2 very fine longitudinal raised lines which continue to the apex. All tibiae with strong teeth on the outer margin and expanded apically beyond the insertion of the tarsi. Front tibia with a single apical spur, middle and hind tibiae with two. Tarsi 5-5-5. Segments 1-4 with fine setae at the apex. Claws smooth and gently curved.