than one-fifth of the subfamily, it has a Holarctic and Afrotropical distribution, although some pest species are now near-cosmopolitan, and is by far most diverse in the Palaearctic region; about 70 occur in the Nearctic region and about 150 in Europe, several species and groups of species have been removed and now form distinct genera, it is a very difficult genus and likely to be split further, it is also certain that many more species will be added. Most of our UK species form part of a much wider continental distribution and in most cases represent only a small part of much larger genera, the greatest diversity here is in Wales and the south of England and most habitats are likely to host at least some species.

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Description

Species within this subfamily are generally easy to recognize and with a little experience will be obvious; they have a distinct rostrum, usually at least twice as long as wide, and the apices of the mesepimera (in the vast majority of species, including all those occurring in Europe)are visible from above between the pronotal base and the elytral humeri. The rostrum can be held ventrally in a wide groove extending between the pro-coxae and in many species with a moderately long or very long rostrum the meso- and metasternum are also impressed between the coxae, these grooves are simple and do not have the raised margins or keels seen in the Cryptorhynchinae Schoenherr, 1825, another subfamily with a well-developed rostral channel. Size varies between 1.2 and 7mm although the majority are 1.5-3.5mm (among our UK fauna the largest is Mononychus punctumalbum (Herbst, 1784), reaching 5.1mm), but despite the small size most are robust and heavily-sclerotized, typically convex ventrally and rather flattened across the elytra, most are drab black, grey or brown but many have patterns of pale scales to the pronotum or elytra and a few are metallic green or blue. In many the entire ventral surface is clothed with broad pale scales, contrasting with the dorsal surface. The head appears small and transverse from above, with convex and usually transverse eyes placed anteriorly and divergent temples which are often retracted into the prothorax, the vertex is simply convex or may have a median impression and is usually densely punctured, in many it is clothed with scales but these may be confined to a median line or absent altogether. Rostrum long and thin, often more than 3.5X longer than broad; least so in Phytobiini Gistel, 1848, smoothly curved or angled with the vertex and with long lateral scrobes hidden from above, antennae long and thin with the scape often abruptly thickened before the apex, funiculus 6 or 7 segmented with at least the basal segments elongate, club 3-segmented and pubescent, often elongate and apically acute, insertions usually near or beyond the middle and often sexually dimorphic. Pronotum quadrate to transverse, broadest at or near the base and narrowed to straight or weakly curved anterior margin, lateral margins unbordered, anterior margin smoothly convex and closely approximated to the head, abruptly raised or finely channelled so appearing as a double margin from in front, usually smoothly curved but sometimes emarginate or with small teeth about the centre. The pronotal surface is usually densely and often strongly punctured although there may be a smooth median line, in many it is strongly sculptured with sub-apical or sub-basal constrictions or lateral tubercles, depressions or raised areas. In most temperate species the elytra are flattened and only slightly elongate, giving the group a distinctive broad-oval appearance, but in exceptional cases e.g. Poophagus sisymbrii (Fabricius, 1776) the form of the mesepimera and the rostral channel is diagnostic. Elytral base straight to strongly bisinuate, with broad shoulders and forming a distinct angle with the pronotum or (e.g. in Scleropterini Schultze, 1902) with sloping shoulders and more-or-less continuous in outline with the pronotum, elytra broadest behind the shoulders or in the basal half and narrowed to rounded or truncate apical margins, usually with well-impressed and punctured striae complete to the apex, interstices flat and simply punctured, tuberculate or raised. The elytral vestiture varies widely; they may be almost glabrous or completely scaled or have a pattern of while or contrasting scales, in many there are raised scales or fine setae obvious along the lateral margins and there is often a patch of pale scales common to both elytra behind the scutellum. In many the pygidium and propygidium are well-sclerotized and visible beyond the elytral apex. The prosternum is usually steeply convex with the anterior margin incised and at least as long as the posterior margin, the pro-coxae round and projecting and widely separated to accommodate a rostral channel. The meso- and meta-coxae are round or weakly transverse and weakly convex, both are widely separated but the meta-coxae may be very widely so. The legs are long and robust and with a little familiarity will be seen to be quite distinctive of the group. The femora are long, generally widest about the middle and curved overall, the front femora vary from smooth to very strongly toothed internally, the middle and hind femora are generally smooth although there may be small internal tooth and all are often constricted before the apex. The tibiae are very variable; usually long and widened gradually to the apex and variously toothed or modified apically or externally. The tarsi are pseudotetramerous, often with the basal and apical segment long and slender and the third segment widely dilated (although there are exceptions e.g. in Eubrychius velutus (Beck, 1817) the lobes are reduced and hardly discernible), and the vast majority have paired claws which are not fused and bear various basal teeth or appendages. Five tribes are recognized in the UK and are easily identified; Mononychini includes a single species, identified by having only one claw on each tarsus, in Phytobiini the rostrum is short and broad, the only exception being some Pelenomus Thomson, 1859 which are otherwise distinct in having two small teeth on the anterior pronotal margin. Rutidosoma globulus (Herbst, 1795), our only representative of the Scleropterini, is distinguished by the rounded elytra with obsolete humeral angles and the strongly tuberculate elytral interstices. Both Amalini and Ceutorhynchini are typical of the group, with well-developed humeri and lacking teeth on the pronotal margin; the only species of the former tribe, Amalus, is superficially very similar to several species of Ceutorhynchini but differs in having the anterior margin of the prosternum entire whereas in Ceutorhynchini it is deeply incised. Although the subfamily is large and specific determination can be very difficult, our UK fauna are, at least to generic and very often to the specific level, fairly straightforward to deal with, more especially so since the publication of the RES handbook by Mike Morris in 2008.   Many species are capable of flight and dispersal over quite long distances and many can retract the rostrum and appendages into the body, resembling seeds, and display thanatosis when disturbed. A few e.g. some Rhinoncus Schoenherr, 1825 are able to jump although they do not have the greatly enlarged femora seen in various Rhamphini Rafinesque, 1815 and this tends to be rather feeble.