THE MAPLE SCALE. 413 



layer of a waxy secretion immediately beginaiug to cover the dorsum. lu a little 

 more than three weeks they have increased to double their size at birth, and undergo 

 their tirst molt, shedding the skin, it is supposed, in small fragments. After this 

 first molt the waxy secretion increases in abundance and a diflereutiatiou 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 fi-om the thorax, the mouth-]>arts 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. 



Meanwhile the female larvse 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 mouth, 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- 

 ishj 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 oft' 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 dasijcarpum), 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 difl^er- 

 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 diff"erent 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 



