17 
The San Jose scale attacks all of our orchard trees, but appears to be 
most destructive to pear and peach. The insect is represented in 
winter by partly grown specimens whose development was stopped by 
the cold weather. They resume growth in the early spring; the 
males soon appear, mate with the females, and the latter give birth to 
living young. At Washington, D. C, this time is about the middle 
of May, and the young continue to appear for about six weeks. The 
larva crawls off a little way, settles, and within two days begins the 
Fig. 
-Aspidiottis perniciosus: a, female; b, margin of pygidium magnified. (Howard and Marlatt.) 
secretion of its scale. This young scale is at first white with a swell- 
ing in the center. If it is situated on green tissue it is apt to pro- 
duce a redness. In a few days the pale scale becomes nearly black, 
with a central nipple surrounded by one or two depressed rings. This 
form is very characteristic of the species. In about twenty -five days 
another brood of males appears, and in thirty days the females become 
adult. At about thirty -five or forty days of age the females begin to 
give birth to living young. Since one of these mother scales may 
have been born six weeks before another, it results that there is a 
24842— No. 34—02 2 
