ARTHROPODS. CLASS INSECTS 125 
In some of the stag- or wood-beetles (Fig. 76), which 
we may select as types, the adults are often found crawling 
about on or beneath the bark of trees, living on sap or 
small animals. The eggs laid in these situations develop 
into grub-like larve, which bore their way through living 
or dead wood, and in this condition sometimes live four or 
five years. They then transform into quiescent pupe (Fig. 
76), which finally burst their shells and emerge in the 
adult form. Others, like water-beetles and the whirligig- 
beetles, whose mazy motions are often seen on the surface 
of quiet streams, pass the larval period in the water. 
Under somewhat different conditions we find the potato- 
bugs, lady-bugs, fire-flies, and their innumerable relatives, 
but the changes they undergo in becoming adult are essen- 
tially the same as those described for the other members of 
the order. 
122. The moths and butterflies (Lepidoptera).— The moths 
and butterflies occur all over the world. In their mature 
Fic. 77.—Monarch-butterfly (Anosia pleaippus). From photograph by A. L. MELAN- 
DER and C. T. BRuEs. 
state they are possessed of a grace of form and movement 
and a brilliancy of coloration that elicit our highest admi- 
ration. The mouth-parts are developed into a long pro- 
boscis, which may be unrolled and used to suck the nectar 
out of flowers, though in many of the adult moths, which 
never feed, it may remain unused. The wings, four in 
number, are covered with beautiful overlapping scales that 
