72 Wisconsin Academy, of Sciences , Arts and Letters. 
A newly born larva is white, with the middle region of the 
body yellow, due to the contents of the alimentary canal. The 
head is pale gray with two prominent black spots, the ocelli. 
The mandibles are brownish in color. Along the sides of tne 
body are whitish specks; these are the spiracles. The skin is 
naked, being without hairs, but fine transverse wrinkles are 
present. When the body is stretched out, as in walking, the 
larva measures about seven millimeters in length. 
A few hours after hatching, even when the larva is not fed, 
it becomes pigmented. The head turns a dark gray, while the 
middle portion of the body becomes yellowish-green, which, 
near the head and anal region, passes gradually over. into a 
white. The spiracles, instead of remaining whitish specks, 
turn black. 
After feeding, the body becomes even darker, assuming a 
grayish color with a green tinge due undoubtedly to the food 
material in the alimentary canal. Posterior to the head, the 
body is a dirty white color, while near the anal region the body 
is darker, due to the contents of the rectum. One noticeable 
peculiarity is that the larva becomes covered with a white, 
fiaky substance which rubs of? very easily. A newly hatched 
larva does not, as the more mature larvae have the habit of 
doing when disturbed, spurt out a watery fluid from certain 
little pores situated on the sides of the body just above the 
spiracles. 
The larvae were fed daily upon the leaves of the peach¬ 
leaved willow. On July 19, five days after the larvae were 
born, the first moult occurred. The larvae do not eat the skins 
cast off. An examination of the moulted skin shows that a 
split extends from the clypeus upward along the median line 
to the dorsal region of the head, and then backward a short 
distance through the dorsal median line of the body, the pos¬ 
terior region of the larva being withdrawn from the skin. One 
peculiarity of a larva which has just moulted, and also of a 
larva which is newly born, is the head, which in proportion to 
the rest of the body is exceedingly large. Soon after the larva 
has moulted the spiracles are hardly discernible, but a few 
hours later they appear as prominent black specks. After the 
