192 LEPIDOPTERA, 



When more observations are made, it may be proved 

 that their migratory movements are periodic, and as 

 regular as the annual migrations of birds. Besides 

 the legs and wings there is the pair of small, hairy 

 shoulder lappets (PL IX., Fig. 135, Ip), already re- 

 ferred to, attached to the mesothorax, which protect 

 the hinge of the wing from injury. 



The metamorphosis of butterflies is indirect. The 

 egg (PI. IX., Fig. 142, much enlarged) of Danais 

 Archippus is dome-shaped, and with its delicate mark- 

 ings is a little gem in itself: it is attached to the under 

 side of a leaf. The eggs are laid from the time the 

 insect appears in June until as late as July and August ; 

 in four or five days they hatch, and the larvae, or 

 caterpillars, are so voracious they begin at once to 

 devour their egg-shells, and afterward the leaves upon 

 which the eggs are placed. In two or three weeks 

 the caterpillar (PI. IX., Fig. 143) has attained its full 

 size. It has a plump, cylindrical body consisting of 

 a head and thirteen similar rings, and is marked by 

 well-defined bands of a brown color. The rings are 

 fleshy and, therefore, more easily creased than if they 

 were chitinous : these creases make the apparent num- 

 ber of rings greater than the real number. There are 

 no compound eyes, but a number of ocelli (PI. IX., 

 Fig. 144, oc^) on the sides of the head. The appen- 

 dages of the small but distinct and chitinous head are 

 somewhat difficult to make out. The antennae (Fig. 

 144, at) are short. The strong mandibles {md) are 

 useful, and are, therefore, movable, unlike those of 

 the mature insect. The first pair of maxillae (;;/x') 

 has two pairs of palpi, while the second pair (;;/x") 



