294 NEW YORK STATE MUSEUM 



young will not survive on a twig cut from the tree, for more than 

 four or five days. 



Observations made on isolated individuals at Washington showed 

 that " the newly-hatched larvas after crawling about for a few 

 hours, settle down and commence at once to form a scale, which is 

 white and fibrous. In two days the insect becomes invisible, being 

 covered with a pale, grayish-yellow shield with a projecting white 

 nipple at the center. ***** Twelve days after hatching, 

 the first skin is cast. ***** I n twenty to twenty-one 

 days after hatching, the females cast their second skin. At 24 

 days the males begin to issue. ***** At 30 days the 

 females are about full grown, and embryonic young can be seen 

 within their bodies ; and at from 33 to 40 days the larvse begin 

 to make their appearance." For additional observations on the 

 development of other broods, see Howard, Insect Life, vii, pp. 

 288, 289. 



From the first brood hatching early in June, a second is undoubt- 

 edly disclosed in July. How many follow, has not been ascer- 

 tained. Matthew Cooke has placed the number during the season, 

 at three, — the first in June, the second in July, and the third in 

 October ; but it would seem that the high temperature of sum- 

 mer could hardly fail of developing at least one additional brood 

 intermediate to those of July and October. Four broods were 

 developed at Washington from over-wintered females, and it was 

 thought that there were ordinarily five. They soon became so inex- 

 tricably mixed that the only importance that could attach to a deter- 

 mination of their number, would be as indicating the rapidity of 

 increase of the insect in different localities and under different sea- 

 sonal conditions. 



The females continue to feed until prevented by the dormancy of 

 the tree in the late autumn. It is thought that most of them pass 

 the winter in about a half -grown stage, and resume their feeding in 

 early spring, as soon as practicable for their entrance upon active 

 life, in June as above stated. 



Its Food-plants 



In addition to the food-plants of the San Jose scale that have 

 been mentioned in the preceding pages, several others have 



