Malthinus

Within the Cantharidae, members of the subfamily Malthininae are characterised by the short, soft elytra which leave the hind wings and the apical segments of the abdomen exposed. In Britain the subfamily consists of only two genera; Malthinus and Malthodes, these can be separated by the presence of a strong tooth on the inner margin of the mandibles in Malthinus (fig.1), in Malthodes the mandibles are simple. This character is obvious but can be very difficult to see. As both genera can be very fragile manipulation of set specimens should be kept to a minimum so it is best to view this character from the underside before setting to isolate the correct genus. Although potentially subjective the two genera can also be separated by the distance of the antennal insertions from the eye, being more distant in Malthinus and closer in Malthodes.

Fig.1

Malthinus consists of only four species in Britain and can be separated by the following key.

1 Head and thorax black, dull and shagreened (front of head yellow in male). Elytra longer almost covering abdomen, entirely pitchy or only obscurely yellow at apex. frontalis - Head and thorax shining, in some part yellow. Elytra short exposing hind wings and apical segments of abdomen. Bright yellow at apex. 2 2 Elytral with obsoletely punctured striae. flaveolus - Elytra with distinctly punctured striae. 3 3 Front of head yellow, remainder black. seriepunctatus - Head black with a small orange mark between antennal insertions. balteatus

M.frontalis (Marsham, 1802) 3-3.5mm. Easily separated from the other Malthinus spp. by the unicolorous black upper surface although the male has a yellow forehead (Fowler, 1887) and the legs are reddish in both sexes. In the male the antennae are much longer than the female. Care should be taken to eaxamine the mandibular tooth as this species can be confused with the darker Malthodes spp. Fowler states they can be recorded by beating fir trees although Alexander (2003) states 'it appears to be associated with large, old, native broadleaved trees'. M.flaveolus (Paykull, 1799) 4.5-5.5mm. The largest of the genus and with the yellow forehead, scutellum and legs could, in the field, be confused for a large M.seriepunctatus however the all orange pronotum and the obscurely punctured elytral striae will serve to separate this species. M.seriepunctatus Kiesenwetter, 1852 3-3.5mm. Head black with forehead yellow. Thorax orange with a central black mark extended the entire length sometimes contracted centrally. Scutellum variously yellow. Elytra light grey darkening towards the bright yellow apical spots. Legs yellow in both sexes. M.balteatus Suffrian, 1851 Head black with a small orange spot between antennal insertions. Thorax as M.seriepunctatus but with the black mark sinuate laterally or gentley constricted rather than 'hourglass'. Elytra darker with a transverse band of grey about middle. Scutellum dark. Hind legs fuscous although Fitton (1973) suggests this is only so in the female. References Fowler, 1887. The Coleoptera of the British Isles L.Reeve and Co Alexander, K.N.A. 2003. Provisional atlas of the Cantharoidea and Buprestoidea of Britain and Ireland. BRC