49<5 
THE STUD V OF INSECTS . 
the larvae of the snout-beetles, are entirely destitute of 
jointed legs. The pupae have the partially developed elytra, 
♦ wings, and legs folded upon the breast, but in dis¬ 
tinct sheaths (Fig. 600). These insects usually 
transform in rude cocoons made of earth or of bits 
of wood fastened together by a viscid substance ex¬ 
creted by the larvse. Many wood-burrowing species 
transform in the tunnels made by the larvae ; and 
fig. 600. some 0 f the Dermestids as well as some of the 
lady-bugs transform in the last larval skin. 
Both beetles and their larvae vary greatly in their habits; 
while some species are very beneficial to man, others are 
extremely noxious. 
More than eleven thousand species of beetles, represent¬ 
ing upwards of eighty families, are known to occur in Amer¬ 
ica north of Mexico. The following synopsis will aid the 
student in learning the relationships of these families:— 
SYNOPSIS OF THE COLEOPTERA. 
{See page 505 for a table for determining specimens.) 
A. The Typical Coleoptera. —Beetles with the head and mouth- 
parts of the ordinary form. 
B. The Isomera (I-som'e-ra).—Typical Coleoptera in which the 
hind tarsi have as many segments as the others. (There are a 
few exceptions to this character among the Clavicornia.) 
C. Isomera in which the fourth and fifth tarsal segments are not 
grown together. 
D. The Adephaga (A-deph'a-ga) or Predaceous Beetles . — 
Isomera in which the first three ventral abdominal segments 
are grown together, and the first of these is divided by the 
hind coxal cavities so that the sides are separated from the 
very small medial part. 
The Tiger-beetles, p. 516.Family CiCiNDELiDiE. 
The Ground-beetles, p. 518.Family Carabid^e. 
The Amphizoids. p. 521 .Family Amphizoida2. 
The Haliplids. p. 522..Family Haliplidal 
The Predaceous Diving-beetles, p. 523. Family DytisciDjE. 
The Whirligig Beetles, p. 525 .Family GYRiNiDiE. 
