TRACHEATA 357 
either free-living, somewhat Myriapod-like grubs, with three 
pairs of well-developed legs, or are soft, white, almost legless 
larvae, which live in the earth or burrow in timber, ete. 
The pupae have their limbs and wing-cases projecting— 
pupa libera. They may be free, or enclosed in rough cocoons 
of earth or wood-chips. 
The very numerous families of the Coleoptera may be 
arranged in four groups, corresponding with the number of 
joints in the tarsus. These divisions have but a slight scien- 
tific value, but are useful in dealing with such an enormous 
number of species as are found in the Coleoptera : 
(i.) The PENTAMERA, with five joints in the tarsus. 
(ii.) The HETEROMERA, with jive tarsal joints on the two 
anterior pairs of legs, and four on the posterior. 
(iii.) The PSEUDOTETRAMERA, with one joint of the five- 
jointed tarsus very small and ineonspicuous. 
(iv.) The PSEUDOTRIMERA, with one joint of the four-jointed 
tarsus very small and inconspicuous. 
Under each of these subdivisions a few families may be 
mentioned. 
Sub-order 1. Pentamera. 
Family CrcINDELIDAE—Tiger-beetles; these have very 
large heads, broader than the thorax, with prominent eyes, 
long curved mandibles, and slender legs. They are usually of 
a brown or green colour with a metallic sheen, and are often 
ornamented with spots or patches. They frequent sunny 
places, such as the sandy margins of streams, and their larvae 
are found in tubular passages in the soil. These larvae are 
provided with two tubercles ending in hooks, which are 
outgrowths of the ninth segment, and which serve to hold 
them to their tubular dwellings; the anterior portion of their 
body projects from the surface of the ground, in order to seize 
any prey which comes within their reach. 
Family CARABIDAE.—A very large family, whose limits are 
difficult to define. They are predaceous insects, with running 
legs, and their hind wings are not infrequently absent. They are 
