5* 
THE STUD Y OF INSECTS. 
Nearly all of our tiger-beetles belong to the genus Cicin - 
dela (Cic-in-de'la), of which there are about sixty North 
v American species; one of these is 
r represented in Figure 620. We 
have also two species of Tetracha 
rv (Tet'ra-cha); see Figure 621. In 
LX the Middle West is found Ainbly _ 
\ child cylindr if orrn A (A m -b 1 y- c h i' 1 a 
cy-lin-dri-for'mis), the giant of the 
Fig. 620. fig. 621. family, measuring one and three 
eighths inches in length ; and on 
the Pacific coast occur nine species of Omits (O'mus). In 
this genus the body is smaller and its thorax larger than 
in Cicindela. These beetles search for their prey only at 
night. 
Family CARABlDyE (Ca-rab'i-dae). 
The Ground-beetles. 
The ground-beetles are so called because they are very 
common on the surface of the ground, lurking under stones 
or rubbish, or running through the grass. Our more com¬ 
mon species are easily recognized by their shining-black 
color and long legs. On the Pacific coast, however, the 
darkling beetles (Family Tenebrionidae), which are also 
black and have long legs, abound under stones and frag¬ 
ments of wood on the ground. But the two families can be 
easily distinguished by the fact that in the ground-beetles 
all the tarsi are five-jointed, while in the darkling beetles the 
hind tarsi are only four-jointed; and the darkling beetles do 
not run rapidly as do the ground-beetles. 
With the ground-beetles the antennae are thread-like, 
tapering gradually towards the tip, and each segment is of 
nearly uniform thickness throughout its length ; the legs are 
fitted for running, and the antennae are inserted between the 
base of the mandibles and the eyes. Although most of the 
species are black, there are those that are blue, green, or 
brown, and a few that are spotted. The wing-covers are 
