ARTHROPODS. CLASS INSECTS 141 



In some of the stag- or wood-beetles (Fig. 82), 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 larvae, which bore their way through living 

 or dead wood, and in this condition sometimes live four or 

 five years. They then transform into quiescent pupae (Fig. 

 82), 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. 



132. The moths and butterflies (Lepidoptera). The moths 

 and butterflies occur all over the world. In their mature 



FIG. 83. Monarch-butterfly (Anosia plexippus). From photograph by A. L. MELAN- 

 DER and C. T. BUUES. 



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 



