Notoxus monoceros (Linnaeus, 1760)
This locally common species occurs throughout the entire Palaearctic region from Portugal to the far east of Russia, China and Japan and extends south into India and South Korea, it is present in South Africa but absent from western Mediterranean Africa, it occurs throughout Europe except for the extreme north but is generally absent from the Atlantic islands. In the UK it is locally common around the coasts of England and Wales and very sporadic inland with most records from the Kent, East Anglia and around the southern Welsh border. Here the typical habitat is dry sandy coastal sites with sparse and patchy vegetation but it frequently occurs inland on dry sandy or clay soils among early successional vegetation, sometimes on set-aside fields, in Kent and East Anglia. Adults occur between April and October, they frequent dry situations on wasteland and field margins but are most readily recorded among plant roots on sand dunes or among strandline debris. They are active on the surface and may also be seen in flight during the warmest days and they may occasionally be found in large numbers; once a few have been spotted on the surface it is usually easy to sieve many specimens from dry sand or among grass roots, they are saprophagous, feeding upon decaying vegetation etc. but may also be found on various flowers where they consume pollen. Larvae develop within sand or soil, usually near the surface and sometimes under stones or debris; they feed on decaying organic material and are fully-grown by the autumn but overwinter in the final instar and pupate within the soil in the spring. Adults obtain the defensive chemical cantharidin from Oil beetles (Meloe spp.) and some flower beetles (Oedemeridae) and will cling to them in order to consume their secretions; they probably detect their hosts by chemical means as dead meloids (M. variegatus Donovan, 1793 and M. violaceus Marsham, 1802) have been used by continental collectors to attract large numbers of adults.
Very distinctive among our UK fauna due to the unique structure of the pronotum. 4.0-5.3mm. Entirely pale brown or yellowish-brown with various dark markings to the elytra; typically around or below the scutellum, laterally in the anterior half and broadly along the suture connecting to a subapical band, but very variable and entirely dark or pale specimens sometimes occur, entire dorsal surface with long semi-erect or erect pubescence. Head elongate with large convex eyes rounded temples, vertex convex, frons and clypeus flat, labrum evenly curved anteriorly. Antennae 11-segmented and filiform, with all segments elongate and more-or-less equal in length, inserted laterally towards the clypeal apex. Pronotum very convex, broadest about the middle and rounded laterally, without angles when viewed from above, strongly raised anteriorly and produced into a horn which projects over the head to the anterior margin of the eyes; this is flattened towards the apex and has a dentate margin. Pronotal surface usually smooth and very finely punctured but at least some transverse wrinkles or impressions are usually evident. Elytra long and only weakly curved laterally, basal margin straight and shoulders rounded, apical margins separately rounded and rather truncate, in the male distinctly notched, surface finely and evenly punctured throughout and lacking striae. The elytra usually cover most of the abdomen but gravid females can become very swollen and have the abdomen substantially visible beyond the elytral apices. Legs long and slender; the femora and tibiae without obvious teeth or apical spurs. Tarsal formula 5-5-4, basal segment of the middle and, especially, hind tarsi much longer than the others, segments 3 and 4 bilobed on all tarsi.