9' 



age. They then insert their bristle-like beaks into the bark and begin 

 to feed. A day or two after settling down they are completely cov- 

 ered by white waxy filaments secreted by glands scattered over the 

 body ; and these filaments soon run together to form a continuous 

 waxy covering. At this stage of development the insect is easily de- 

 tected; but in a few days the waxy covering becomes dark and very 

 difficult to detect with the unaided eye, especially on a dark surface. 

 When viewed with a hand lens, however, it looks not unlike a minia- 

 ture volcano, having the shape of a very low cone with a circular 

 ridge at the apex, inside of which is a nipple-like elevation. As the 

 insect grows the scale enlarges, the female scale remaining almost 

 circular with the nipple near the center (PI. II., Fig. 2), and the male 

 scale becoming about twice as long as wide, with the nipple near 

 one end (PI. II., Fig. 3). In summer or fall, examples of all these 

 stages may be seen on the bark of an infested tree, but in winter and 

 early spring only the small, dark, immature scales and the mature 

 males and females are found. 



Scattered specimens of the San Jose scale are difficult to find, 

 but they may be discovered with the aid of a good pocket-lens. When 

 numerous, the crawling young and those in the white stage may be 

 readily detected with the unaided eye; when the bark is heavily in- 

 fested with mature insects it becomes completely incrusted with thei-' 

 waxy coverings and has a rough, ashy-gray appearance which is easily 

 recognized. Parts of trees so infested are usually seriously injured. 

 The unhealthy appearance of a tree or limb during the growing sea- 

 son is therefore an indication of the possible presence of the scale, 

 and should lead at once to a careful examination. On fruit and on 

 tender bark the scale produces a conspicuous red spot, and by watching 

 the fruit the orchardist may usually detect its presence in bearing trees 

 before it has caused serious injury. 



When mature, the male comes out from under its waxy covering 

 as a very dehcate two-winged insect (Fig. 1). The female (Fig. 2) 

 remains alive under her covering for about six weeks after reaching 

 maturity, gives birth to a new generation, and then dies. 



The winter is passed in an immature stage, on the bark of the host 

 plant. In spring the hibernating individuals continue their growth and 

 mature usually about the latter part of May, and by the first of June 

 the young of the first generation begin to appear, the time varying 

 greatly with the latitude and character of the season. In an experi- 

 ment made by James A. West, of the State Entomologist's staff, at 

 Urbana in 1908, the first young appeared May 30, and reproduction 



