64 
of 3,410. In central Illinois the eggs ordinarily hatch in June, and 
in the northeastern part of the state in early July, or later if the 
weather of the time is unfavorable. Virtually all are hatched, as 
a rule, by the end of July. 
When first hatched the six-legged young (Fig. 65, a, e, f) move 
slowly about as creeping yellowish specks about twice as long as 
wide. They soon settle upon the leaves, mostly upon the under side 
Fig. 65. Cottony Maple Scale, Pulvinaria vitis, immature stages: a, newly 
hatched young, under side; b. c, j'oung female, top and side views; d, 
young male; e,/, young on leaf and leaf stem. Natural size shown in a. 
along the veins, but a considerable percentage also on the upper 
surface. Soon after settling down, a thin waxy layer forms on the 
back, and in about three weeks the insect has virtually doubled in 
size. As they increase in size the male and female scales become 
distinguishable (Fig. 65, h, c, d) by the fact that the former are 
comparatively narrow and more convex. From these tlie winged 
males (Fig. 66, a, b, c) emerge to fertilize the stationary females 
in August and September, perishing soon thereafter. In autumn 
the young females migrate from the leaves, which are about to fall, 
to the twigs, upon which they pass the winter and, indeed, the re- 
mainder of their lives. In spring the female scale (Fig. Sy) is ellip- 
tical, convex on the back, with a low, rounded, median ridge. It is 
pale greenish or whitish yellow, marked with black or dark brown. 
When full grown, about the middle of May, it is 4 to 6 mm. long 
and 3 to 4.5 mm. wide. Its body is at first closely applied to the sur- 
face of the twig, but with the development of the eggs beneath it the 
abdomen is gradually raised from the bark to an angle of forty-five 
degrees or more. 
It is usually difficult to say whether trees infested by this insect 
should receive special treatment, or whether they may be safely left 
