852 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



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 larvce have been undergoing but slight changes 

 of form. They grow lsarger and also broader across the posterior por- 

 tion, but remain flat and with but a slight indication of a dorsal carina. 

 Just before the appearance of the adult males, tbey 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 Septem- 

 ber 15, issuing most abundantly about the middle of the former month, 

 and their life is short, seldom exceeding two or three days. They cop- 

 ulate with the females and then die. The latter, soon after the disappear- 

 ance of the males, gradually lose their fright-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 underside. 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 yellowish, 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 posterior 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 an- 

 gle 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-laying 

 that the insect is noticed, on account of its large size, but more particu- 

 larly 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, Eose, 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 dif- 

 ferent 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 ac- 

 count simply with the words: "I do not feel fully prepared to agree 

 with Mr. Biley and Miss Smith in regarding all the Fulvinariw found on 



