264 Arthropoda. 



1. The OarabidsB (genus Carahus, and many others), active, slim,, 

 usually dark-coloured beetles, with long powerful legs ; antennse filiform, 

 mandibles slender, projecting; first maxilla with a two-jointed laoinia. The 

 tarsi of the first pair of limbs in the males are very often broad and hairy below, 

 enabling them to hold the females firmly; the other tarsi are long and thin. In 

 not a few the hind wings are rudimentaiy. The lai-vse, which, like the adults, 

 are almost always predaceous, are usually darkly-coloured, with a gi-oup of 

 ocelli on each side, and with well- developed legs, each with two claws ; in other 

 coleopterous larvae there is usually only a single claw on each foot. The Tiger- 

 beetles {Cicindela) are small Oai-abids characterised by their bright colours, 

 (green, etc.). The larva is paler than that of most of the Carabidse, and exhibits 

 a pair of hooks on the back ; it lives in a bun-ow in the gi-ound, where it lies in wait 

 for its prey. The Dytiscidae (genus, Dytiscus, and others) are to be regarded 

 as a type of Oarabidse specially developed for an aquatic life ; in most respects 

 they resemble the Carabids, but differ from them in the broad, oval body, and in 

 the modification of the hind legs as natatory organs, the tarsi being broad and 

 hairy at the edges. In the males, the first three joints of the front tarsi are stiU 

 broader than in the Oarabidse, and are furnished with ventral suckers (modified 

 setae). They come to the surface to breathe ; by night they usually leave the 

 water and fly about. The larvse aa-e also aquatic, and are slender: the 

 legs are friuged with setse ; their most striking peculiarity consists in. the 

 perforation of the thin mandibles by a fine canal, which opens at the tip and 

 leads at the other end into the mouth (the canal is really a groove with apposed 

 edges, c/., the poison tooth of snakes), whilst but for this the mouth is completely 

 closed. The prey is sucked out by these mandibles. Allied to the Dytiscidse is. 

 another group of Water-insects, the Whirligigs {Qyrinus), small forms which 

 usually swim about actively on the surface of the water ia the sunshine. They 

 are distinguished by several features : the middle and hind legs are modified to 

 form shoi't, broad, flattened, fin-like natatory organs, whilst the longer front legs 

 are normal in structure, and are used as organs of attachment when the insect 

 dives. Each eye is divided into an upper and a lower portion, of which the 

 former looks upwards, the latter downwards. The larvre correspond with those 

 of the Dytiscidse in the structui-e of the mandibles, etc., but differ from them in. 

 the possession of closed stigmata and a row of filiform branchise along the sides of 

 the abdomen. 



2. Staphylinidse (genus Staphylinws, and others), distinguished by the 

 small size of the elytra; the larger portion of the very movable abdomen is 

 uncovered, but it is well chitiaised dorsally ; the hind wings are folded across 

 twice, in order to find room under the elytra. The body is elongate, the 

 antennae filiform, or somewhat clavate. The adult genei-ally lives upon decaying 

 plant and animal substances. The 1 a r v se are like those of the Oarabidse, but 

 possess only a single claw on each foot (or more coxTectly, the tarsus itself is 

 pointed) ; they are provided with two jointed oerci, and the anus is situated on a 

 tubular projection. They feed as do the adults, or are predaceous. This family 

 is extraordinarily rich in species. 



3. The Carrion-beetles {Silphidm) have the antennae clavate, or at least, 

 somewhat thickened at the tips. In some forms, the elytra cover the whole of the 

 abdomen; in others, its tip is left uncovered. They are, as a rule, cariion- 

 feeders. The genus Silpha has slightly clavate antennse, elytra covering the 

 whole of the abdomen, and the body of a flat, oval form. The larvse are broad 

 and flattened, firmly chitinised, and they forage for themselves ; both larvss 

 and adults usviaUy feed upon dead animals, for which they seek. The 

 Burying-beetles (Necrophorus) have markedly clavate antennae, elongate 

 bodies and short elytra usually coloui-ed with black and red bands, leaving the 



