Amphicyllis globus (Fabricius, 1792)
POLYPHAGA Emery, 1886
STAPHYLINOIDEA Latreille, 1802
LEIODINAE Fleming, 1821
AGATHIDIINI Westwood, 1838
Amphicyllis Erichson, 1845
This widespread Palaearctic species occurs continuously from Spain to the far east of Russia, in Europe it is present on most of the Mediterranean islands but seems to be absent from Corsica, Sicily and Crete, and extends north to the UK and to the Arctic Circle in Scandinavia. In the UK it is very local across southeast and central England and sporadic and rare further north to the Scottish border and in Ireland. Typical habitats are broadleaf, conifer and mixed woodland and wooded parkland with plenty of older trees in various staged of decay. Adults occur from April until late in the autumn and peak in abundance during May and June, they are often associated with various fungi, especially Fomes fomentarius (L.) Fr. 1849, in which the larvae are thought to develop. Searching sporocarps is the best way to sample them but they often occur randomly while working wood; they are crepuscular and nocturnal and so may be found by nocturnal searching. They are often active by night on the surface of branches or trunks and they sometimes visit sap runs but they spend the day hidden among leaf-litter and fallen pine needles etc. or in soft decaying wood or under dead bark. Care needs to be taken when searching at night as when disturbed they will fall to the ground, roll into a sphere and remain still for long periods, they usually occur as single specimens but pairs are common early in the season and at this time if one specimen is found then another is likely to be nearby. On the continent hey have been recorded from wood and bark of a wide range of broadleaf and conifer trees, sometimes in burnt areas, and so it is likely that any fallen timber or trees in the right habitat are worth searching.
2.5-3.5 mm. Glabrous, strongly convex and almost hemispherical, typically with the head and elytra black and the mouthparts, pronotum and appendages pale reddish-brown. Head transverse, very finely punctured and almost flat between weakly convex eyes, temples strongly converging and frontoclypeal suture weak. Antennae inserted laterally in front of the eyes, 11-segmented with a long 4-segmented club. Pronotum strongly transverse, broadest at obtuse posterior angles and narrowed to widely rounded anterior angles, surface evenly convex and very finely punctured. Elytra quadrate, very convex, randomly punctured throughout, a little more strongly so than the pronotum, although irregular longitudinal series are often present on the disc, lateral margins sinuate and finely bordered. Ventral surface red with the metasternum and abdomen black, in f. ferrugineum Sturm the entire underside is red. Tarsi 5-5-4 in males, 4-4-4 in females, in males the front tarsi are strongly expanded. Similar in colour and habitus to Agathidium nigripenne (Fabricius, 1792) but here the antennal club is 3-segmented (a feature that will distinguish globus from all similar UK species) and the head is pale.