300 BOARD OF AGRICULTURE. [Pub. Doc. 



frequently results in the discovery of multitudes of the 

 minute, dark-gray, circular or slightly oval scales massed on 

 the trunk and older branches, while the younger growth is 

 thickly dotted with single scales. The scales are often so 

 numerous on the trunk as to make a thick, scurfy crust, that 

 may be removed in a layer. While most commonly found 

 on the bark, they also occur on the fruit and leaves. The 

 writer has found this insect abundant on the fruit of the 

 Japanese quince, and in a single orchard on apples and 

 pears. When the scales occur on the fruit or young growth, 

 they are often bordered with a purplish margin of discolored 

 tissue. On the bark beneath the scales a similar coloring is 

 found ; but this peculiarity is not confined to the San Jose 

 scale, since the scurfy bark louse sometimes produces the 

 same effect. This discoloration of the bark, however, is 

 of considerable assistance in the recognition of the San Jose 

 scale in the field. 



The nearly mature insects winter over beneath their 

 scales, and complete their growth early in the spring. Dur- 

 ing a period of about six weeks the females give birth to 

 several hundred young, and at the end of this time the first- 

 born insects are mature. The young larvae, after escaping 

 from beneath the female scales, appear as a fine, yellowish 

 dust on the bark, and swarm over the tree in search of a 

 suitable settling place. Having become fixed, they insert 

 their beak into the bark, secrete a scale, and soon become 

 like their parents in appearance and capacity for damage. 

 The active season of the insect is doubtless shorter in Massa- 

 chusetts than it is farther south. Accurate information on 

 this point is lacking. On May 21, 1898, I found young 

 larva? abundant on a badly infested, purple-leafed prune at 

 Cambridge, Mass. ; while at Auburndale, Mass., Oct. 9, 

 1897, a few days after a light frost, infested peach trees 

 were swarming with the young lice. This shows us that 

 here the insect multiplies throughout a season of over four 

 months. 



By isolating female scales on small trees, Messrs. Howard 

 and Marlatt found the number of young borne by a single 

 female to vary from thirteen to five hundred and eighty- 

 seven ; and, assuming four hundred young to be a fair 



