Triphyllus bicolor (Fabricius, 1777)
This is a widespread but generally very local species throughout western and central Europe, extending north to the UK and the very southern provinces of Norway and Sweden and south to the Mediterranean although it is absent from some of the south eastern countries, it is present on various Mediterranean islands and extends east through Asia Minor and into western Russia but is absent from North Africa. In the UK it is locally common throughout lowland England and Wales though absent from the far west, typical habitats are deciduous woodland and wooded parkland with plenty of mature trees in various stages of decay, adults occur from early in the year until October or November, they are nocturnal and will generally be found in the vicinity of fungal fruition bodies on older trees , stumps or larger fallen branches, they usually occur in numbers although they fly well and on warm spring and summer nights individual specimens may occur away from typical habitats. Mating occurs in the spring when adults emerge from their overwintering quarters, this occurs at night and usually among bark or on fungi and females oviposit in fruiting bodies soon afterwards, the most frequently recorded host is beefsteak polypore (Festulina hepatica (Schaeff.) With (1792)) but larvae have also been reared to adults from chicken-of-the-woods (Laetiporus sulphureus (Bull.) Murrill (1920)) and adults have been recorded from a wider range of fungi including the appropriately-named common stinkhorn (Phallus impudicus L. (1753)), oyster mushroom (Pleurotus ostreatus (Jacq ex Fr.) P. Kumm (1871)) and P. ulmarius (Bull.) Fr.). Larvae develop within the fungus through the spring and early summer and when fully-grown they drop to the ground and burrow into the soil to pupate. New-generation adults appear during August and September and these are usually active for a while before entering the ground beneath host trunks etc to overwinter although they will occasionally occur among extraction samples of bark and debris during the winter. Adults may be sampled by beating likely sporophores over a net but they are easily spotted at night by torchlight and might occur among extraction samples at any time of year.
3.5-4.0 mm. Easily recognized by the bicoloured dorsal surface; typically with the forebody pale brown, elytra pale brown with a wide transverse dark band which extends more narrowly to the apex, legs pale brown and antennae darker brown, in most specimens the elytral colours are well demarked and the pattern is distinctive but this varies and the dark marks may be very reduced and diffuse. Elongate-oval and convex, dorsal surface shiny and without obvious microsculpture, moderately strongly and densely punctured and with fine golden pubescence. Head transverse with small convex eyes, vertex and frons flat and without sculpture, frontoclypeal suture strongly impressed and anterior clypeal margin curved and produced about the middle, labrum wide and truncate. Antennae inserted laterally in front of the eyes, 11-segmented with an abrupt 3-segmented club. Pronotum strongly transverse, broadest at rounded posterior angles and narrowed to a curved apical margin, the anterior angles absent or barely suggested, basal margin weakly sinuate and with only a hint of a border towards the angles, surface evenly convex and without basal fovea or impressions. Elytra long-oval and convex, the lateral borders not visible from directly above, broadest about the middle and gently-curved to finely-rounded humeral angles and a continuous apical margin that completely covers the abdomen, across the base distinctly narrower than the width of the pronotal base, without striae and evenly punctured throughout. Legs long and slender, the femora only narrowly visible in normal setting, tibiae smooth and hardly widened from the base, each with several short spines at the apex but without distinct apical spurs, the front tibiae with several small spurs among the pubescence along the outer margin. Tarsi 4-segmented in the female, 3-4-4 in the male, the segments not obviously lobed and the basal segment of the hind tarsi at most as long as the terminal segment, claws long and slender, smooth and without a basal tooth.