298 NEW YORK STATE MUSEUM 



duced. The winter is passed in the egg under the protecting scale of the 

 female, the young appearing from the middle of May to early June, and in 

 the case of badly infested trees parts of the twigs may be literally yellow 

 on account of the abundant crawling specks. Prof Lowe has observed 

 them as early as May 7 at Geneva (N. Y.) They soon setde in a place 

 and begin sucking nourishment from the underlying bark tissues, and in 

 about two days long, white, waxy filaments extend from the back of the 

 young, and, where they are numerous, the infested branch is adorned 

 with patches of woolly-appearing matter, as shown in figure 3. This excre- 

 tion mats down and soon forms a protective covering. Close inspection 

 shows this to be composed of a cast skin and a larger scale formed by the 

 matted filaments adhering to it. Such half-grown insects, represented in 

 figures 4 and 5, are about six weeks old. Another molt occurs later, and 

 to this second cast skin a much larger scale is attached. The first cast 

 skin and its scale are on top of the anterior part of the second, but are 

 easily dislodged and therefore may not be observed. The fully developed 

 female may be found beneath the larger scale about the first of August, 

 egg-laying beginning soon and being completed by the latter part of the 

 month or early September. One female deposits from about 50 to 100 

 eggs. Prof. Comstock states that, while he found the male scale rare 

 on appletrees at Washington, it was abundant on other kinds of trees. 

 The attacks of this insect are confined almost wholly to the bark, though 

 there are a few records of the species occurring on fruit. 



Food plants. This species is of greatest importance on account of 

 its depredations on fruit trees, but it also occurs on a large number of 

 other plants. The brief list of food plants brought together by Dr Lint- 

 ner in his nth report includes most of the more important species. It 

 is as follows : apple, plum, pear, raspberry, wild cherry, wild gooseberry, 

 red currant, sugar and swamp maples, white and black ash, birch, poplar, 

 willows, linden, horse-chestnut, elm, etc. Dr L. O. Howard, writing of 

 this insect in 1895, gives two Hsts of food plants, a number of which are 

 not represented in the above enumeration, and he proceeds to state that, 

 though no structural differences have been found between the forms on 

 these varied food plants, he can hardly avoid the strong suspicion that 

 certain of these will not interbreed, and that eventually distinguishing 

 characteristics will be found to exist. 



Natural enemies. A small hymenopterous maggot was observed by 

 Dr Fitch to live on the eggs of this pest. What was in all probability the 

 same parasite was described by Dr Le Baron some years later as A p h e I i- 



