THE COTTON-WORM. 359 
The larger moths are represented: by the canker-worm, 
the grass army-worm (Fig. 351), and the cotton army-worm 
(Fig. 352), so destructive to 
vegetation; the silk- worm 
moth (Bombyx mori Linn.), 
of the Old World, and the 
American silk-worm (Telea 
Polyphemus Linn.) Certain 
species of the silk- worm 
family, called basket-worms 
(G@eeticus), live in cases con- 
structed of short or long strips 
ah di 352.—Egg, caterpillar, and moth (Fig. 353. Our native species 
letia argillacea, the Cotton Army- ig Thyridopteryx ephemereefor- 
mis Haworth. 
The hawk-moths (Sphinz) are distinguished by their 
large size and very long tongue. The butterflies differ from 
the moths in having knobbed anten- 
nz, while the chrysalides are often 
ornamented with golden or silvery 
Spots. 
Order 16. Hymenoptera.—The bees 
stand at the head of the insect series 
in perfection and specialization of 
parts, especially the organs of the 
mouth, and from the fact that in the 
course of the metamorphosis from 
the larva to the pupa the first ab- 
dominal segments become transferred 
to the thorax—a striking instance of 
the principle of transfer of parts 
headward. In the large head, spheri-'' 
cal thorax, and short, conical abdo- 
men, the bees are opposed : to, the 
dragon-flies and ‘other Neuroptera, 
a ae 
in which the abdomen is long, the pig, 353.—Cases of African 
thorax composed of three homogene- 
ous segments, and the mouth-parts only adapted for biting. 
In the bee there is a marked differentiation of the parts of 
