THE MAPLE SCALE. 413 
layer of a waxy secretion immediately beginning to cover the dorsum. In a little 
more than three weeks they have increased to double their size at birth, and undergo 
their first molt, shedding the skin, it is supposed, in small fragmeuts. After this 
first molt the waxy secretion increases in abundance and a differentiation between 
the sexes is observable. The males grow more slender and soon cease to increase in 
size, covering themselves with a thick coating of whitish wax. The pupa then 
begins to form within the larval skin, the appendages gradually taking shape, the 
head separating from the thorax, the mouth-parts being replaced by a pair of ven- 
tral eyes. A pair of long wax filaments is excreted from near the anus and these 
continue to grow during the life of the insect. It is the protrusion of these filaments 
from beneath the waxy scale which indicates the approaching exclusion of the male. 
The posterior end of the scale is in this manner raised up, and the perfect insect 
backs out with its wings held close to the sides of its body. 
Meau while the female larva} have been undergoing but slight changes of form. 
They grow larger and also broader across the posterior portion, but remain flat and 
with but a slight indication of a dorsal carina. Just before the appearance of the 
adult males, they undergo another molt and change in color from a uniform pale 
yellow to a somewhat deeper yellow with deep red markings. (Fig. 3, a, b, c.) 
The males (Fig. 2, c) make their appearance from August 1 to September 15, 
issuing most abundantly about the middle of the former month, and their life is 
short, seldom exceeding two or three days. They copulate with the females and 
then die. The latter, soon after the disappearance of the males, gradually lose their 
bright-red markings and change to a deep-brown color. They grow more convex, and 
the dorsal layer of wax becomes thicker and more cracked. Before the falling of 
the leaves they migrate to the twigs and there fix themselves, generally on the under 
side. After feeding as long as the sap flows, they become torpid and remain in this 
condition until spring. 
At the opening of spring the eggs develop with great rapidity and distend the 
body greatly, causing it to become convex instead of flat. The color is now yellow- 
ish, marked with dark brown, and the insect now absorbs sap with great rapidity 
and ejects drops of honey-dew. From the middle of May to the first of June the egg- 
laying commences. The eggs are deposited at the end of the body, in a nest of waxen 
fibers secreted from pores situated around the anus. This nest is attached to the pos- 
terior ventral portion of the body, and adheres somewhat to the twig. As the eggs 
are protruded into the waxy mass the posterior portion of the body is gradually 
raised up until it often reaches an angle of forty-five degrees with the bark. The 
egg-laying continues until on into July, and, after one or two thousand eggs have 
been deposited, the female dies. It is almost always within this period of egg-lay- - 
ing that the insect is noticed, on account of its large size, but more particularly from 
the conspicuous white cushion at the end of its body. After the death of the female, 
her beak breaks off and her body shrivels up, but remains attached to the twig by 
the cottony mass for a long time, often a year or more. 
Food-plants. — The ordinary food-plant of this species of bark-louse is the soft or silver 
maple (Acer dasycarpum), but previous to 1879 we had not only found it upon the 
other species of maple, but also upon grape-vine, osage orange, oak, linden, elm, 
hackberry, sycamore, rose, currant, and spindle tree (Euonymus). In addition to 
these plants Mr. Putnam mentions locust, sumac, wild-grape, box-elder, beech, and 
willow. With regard to the specific identity of the individuals from all these differ- . 
ent plants there is still room for doubt, though in 1875 we successfully transferred 
the species from Madura and Vitis to Quercus. We wrote Mr. Putnam under date of 
March 25, 1879 : " In all essential external characters they are identical, and, until 
they are shown to be different by the character and arrangement of the secretory 
pores in the anal plate of the female, they must be assumed to be identical. It is 
this critical^ comparative study which would greatly increase the value of your 
work." This study Mr. Putnam failed to make, and summed up his account simply 
