1. Apalochrini Mulsant & Rey, 1867 includes 14 genera and more than 110 species but the majority occur in eastern Asian regions and only 10 species of 3 genera extend into Europe, these are mostly of very restricted distribution but Apalochrus femoralis Erichson, 1840 is widespread.

2. Illopini Jakobson, 1911 includes 3 genera and 38 species and is restricted to Asia; the 35 species of Condylops Redtenbacher, 1850 are all restricted to various regions of China.

3. Troglopini Mulsant & Rey, 1867 includes almost 150 species of 11 genera and is primarily Asian but several occur in Europe and North Africa. Only 2 species are widespread in Europe: Troglops albicans Linnaeus, 1767 and T. cephalotes (Olivier, 1790), the latter extending to the UK. Troglops Erichson, 1840 is otherwise represented in Europe by 17 species and in the wider Palaearctic by 66 species.

4. Ebaeini Portevin, 1931 includes about 350 Palaearctic species in 17 genera and is almost entirely restricted to Asia, especially China, with only a few of the 2 largest genera extending to Europe. Of the >150 species of Ebaeus Erichson, 1840, 27 occur in Europe and a single very widespread species, E. pedicularius (Linnaeus, 1758) extends to the UK. Hypebaeus Kiesenwetter, 1863 includes 110 Palaearctic species; 8 occur in Europe and of these the very widespread H. flavipes (Fabricius, 1787) occurs in Britain.

5. Colotini Abeille de Perrin, 1890 includes 58 Palaearctic species of 9 genera and is mostly Asian but 2 genera extend to Europe; of the 6 species of Pelochrus Mulsant & Rey, 1867 4 are European, and of the 40 species of Colotes Erichson, 1840 10 occur in Europe and the single widespread species C. punctatus (Erichson, 1840) extends to the UK.

6. Attalini Abeille de Perrin, 1890 includes 7 genera and about 320 Palaearctic species; more than 40 occur in Europe, mostly of the genus Attalus Erichson, 1840, and many more in North Africa but the group is otherwise mostly eastern and only the very local European and North African Sphinginus lobatus (Olivier, 1790) extends to the UK.

7. Malachiini Fleming, 1821 includes about 350 Palaearctic species in 16 genera; it is most diverse in eastern regions but is well-represented in Europe and members of several large and widespread genera occur in the UK.  Of the 39 Palaearctic species of Anthocomus Erichson, 1840 13 occur in Europe and 2 extend to the UK. The Holarctic Axinotarsus Motschulsky, 1854 includes 35 Palaearctic species of which 14 are European and 3 are British. Clanoptilus Motschulsky, 1854, sometimes considered as a subgenus of Malachius Fabricius, 1775, includes >100 Palaearctic species, almost 40 occur in Europe and 3 extend to the UK. Cordylepherus Evers, 1985 includes 14 Palaearctic species, 5 occur in Europe of which the very widespread and common Eurasian C. viridis Fabricius, 1787) extends to the UK. Malachius is a mostly Asian genus of about 75 species in 2 subgenera, 30 extend to Europe and of these the 2 most widespread extend to the UK. The six species of Cerapheles Mulsant & Rey, 1867 are western Palaearctic and all but the Azerbaijan endemic C. hauseri Pic, 1907 occur in Europe; with the exception of the widespread Eurasian C. terminatus (Ménétries, 1832), which extends to the UK, they are of very limited distribution. With representatives of some of the larger genera our UK fauna provides an insight to the family as a whole and allows a good appreciation of the general morphology of the group.

​

Description

Members of this group are small to medium size beetles, 1-8mm, many are brightly coloured or patterned with red, yellow, orange or white and many are metallic blue, bronze, copper or green. More generally species vary from entirely dull black to dark metallic or with discreet areas of colour margined with contrasting metallic margins. Most are smooth and lack any larger structure, finely punctured and possess a double pubescence. Most are dorsally flattened and elongate, parallel-sided to broadly oval and usually widened posteriorly, in many the elytra do not completely cover the abdomen and extreme cases the species resemble rove beetles. Some species of e.g. Paratinoides Medvedev, 1964 or Embrocerus Peyron, 1877 (Malachiinae) have reduced hind wings but most have fully developed wings and are active diurnal fliers. A very distinctive feature of the family are eversible structures on the lateral margins of the thorax and basal abdominal segments which are most developed in males but also sometimes occur in females, these have ducts from pheromone glands, called ‘excitators’, and are used to attract mates and stimulate mating behaviour, the secretions being actively consumed by the females, males are often otherwise modified with processes on the antennae, head, pronotum, metathorax, abdomen or legs and the elytra may be modified with pits, plica or more complex structures. These structures are often species- or group-specific and used in the systematics of the family. The following brief description applies to the family generally. 1.0-8.0mm. Elongate-oval and usually discontinuous in outline, soft-bodied and variously flattened, colour very variable (as above) but the eversible vesicles vary from yellow to red. Dorsal surface usually shiny and only finely punctured although a distinct microsculpture is usually present and the elytra (especially) may be finely rugose. Pubescence generally doubled, consisting of fine, dense recumbent pubescence and longer erect setae although this is variable and almost glabrous species occur. Head usually prognathous, only occasionally declined, with flat to very convex eyes which are entire or weakly emarginate, and a distinct frontoclypeal suture, sometimes produced anteriorly, clypeus prominent and trapezoidal and labrum transverse to quadrate, only rarely elongate. Temples usually long and converging to the base but often at least partially hidden within the prothorax. Mandibles elongate; sharp apically or bidentate, mola and prostheca absent or reduced and the incisor edge often denticulate. Maxillary palpi 4-segmented with all segments narrow and elongate. Antennae 11-segmented, only rarely 10-segmented, inserted laterally in front of the eyes, the insertions visible from above, robust and relatively long, filiform, serrate, pectinate (e.g. in the European Haplomalachius flabellatus (Frivaldzsky, 1835) or to some extent incrassate. Males generally have modified antennae, often with the inner margins of the basal segments enlarged, sometimes greatly so e.g. in species of Collops Erichson, 1840. Prothorax, metathorax and abdomen with eversible vesicles in males. Pronotum transverse to quadrate, only rarely elongate, evenly convex to flat and widely explanate and often with widely rounded posterior angles and a continuously rounded anterior margin. Broadest at or behind the middle and usually with a complete lateral border.  Prosternum variable in front of round to transverse coxal cavities, process very variable. Scutellum visible and usually relatively large, flat broadly rounded to truncate.  Pro- and mesocoxae conical and projecting, metacoxae transverse and weakly convex. Trocantins broadly exposed, trocanters long and obliquely joined to the femora, femora long and at most only weakly broadened at the middle, tibiae long, often curved and usually near-parallel, tarsi 5-segmented, the segments ventrally lobed, claws with a variable fleshy ventral appendage. Abdomen with 6 visible sternites. Elytra typically with well-developed shoulders and broadened to a continuously rounded apex, lacking striae and randomly and finely punctured, in some they are truncate or obliquely truncate with the outer angle produced into an acute angle. In most species at least some of the abdominal segments are exposed beyond the elytral apex. Larvae are elongate, slender and, apart from the head and the ninth tergum which bears a pair of urogomphi, weakly sclerotized and many are pink or red in colour.

​

Ecology

Worldwide the greatest diversity occurs in arid biotopes and semi-desert areas; the family is thought to have originated around the Mediterranean area as this is rich in both species and higher taxonomic groups. Adults typically occur in the spring and summer and have a short season, they often occur on the flowers and foliage of herbaceous plants and shrubs and many are active in hot weather when they may be found in large numbers, others occur on trees and some are nocturnal. They feed on pollen and fungi and also on small insects visiting flowers and many are known to pollinate flowering plants, the dense pubescence and setae on both the dorsal and ventral surface of most species traps pollen grains which are transferred between flowers. Larvae occur in a wide range of habitats, the majority probably develop among leaf litter or in the soil but many occur in herbaceous plant stems or among dead wood or under bark where they inhabit galleries and predate other insects. They are typically predatory but some are known to be scavengers on carrion or material of animal origin, some predate the larvae of nest-building Hymenoptera and some are known to feed on larvae and pupae of alfalfa weevils (Hypera postica Gyllenhal, 1813) although none have been used in biological control.