240 SCALE-INSECTS, BARK-LICE, MEALY-BUGS. 
of the larger varieties of the oyster. The scale is about one- 
sixth of an inch long, of a brownish or grayish color, and so 
closely resembles that of the bark on which it occurs, that it 
is frequently overlooked when occurring in small numbers. It 
is a northern species, introduced from Europe nearly a hundred 
years ago, but it is now found almost everywhere in apple 
orchards, and also in some nurseries. The species is single- 
brooded, but further south two generations are produced. The 
eggs are deposited during autumn, and are found below the 
female scale, where they winter, in large numbers. Towards the 
middle of May the white eggs change to a yellowish hue before 
hatching, and give forth the active yellow larve, which, after 
Fig. 193.— Parasite of San Jose Scale. After Div. of Entomology, Dep. of Agri- 
, culture. 
running about for a short time, settle, and inserting their beaks 
draw nourishment from the trees. As we find from twenty to 
one-hundred or more eggs under each scale the branches of the 
apple tree soon become literally covered and crowded with scales, 
and they seriously impair the health and vigor of a tree thus 
infested. The leaves, even the young apples themselves, are 
also invaded and injured. The larve, after becoming fixed, con- 
tinue to grow in the usual manner until after the midsummer. 
As may be seen from the illustration (Fig. 192) and on Plates 
XIV and XVI, the sexes are quite different. The male mature 
late in July or August, seek the females, and then die. A little 
