314 
COLEOPTERA. 
insects, scarcely as much, as a quarter of an inch long and nearly 
always the dull black or deep brown of wood-boring and light-shun- 
Fig. 193. —Bostrychus .equalis—larva, imago and bored wood. [I. M. N.] 
ning insects. The body is cylindrical, the integument thickened and 
hard, the structure compact and the insect well fitted for boring tun¬ 
nels in wood. The legs are short, the femora and tibiae broadened, 
folding up under the body, the trophi are well developed and powerful. 
In many the front of the prothorax overhangs the head and is toothed 
and roughened, while in some the body terminates behind in a flat slope 
in which are tubercles, as if the hind end had been cut off obliquely 
and tubercles put in for the beetle to get a purchase on the sides of the 
tunnel. Males and females are alike in appearance, the former the 
smaller. t 
The life-history of some species is known and details must be sought 
in the literature of forest insects. In general, the beetles bore tunnels 
in wood, depositing eggs in these tunnels ; the larvae are white, the body 
white, soft and tapering behind, the apex curled round underneath. 
Thoracic legs are usually present, eyes are absent and there are small 
four-jointed antennae. The larval food is the same as that of the 
imago ; pupation takes place in the larval tunnel, no cocoon being 
formed. In the known common plains species there are at least two 
broods yearly, the beetles emerging after the cold weather, a brood 
