THE EUROPEAN ELM SCALE IN THE WEST. igt 
ACTIVITIES OF THE FEMALE. 
The hibernating female larve begin their activities a little later 
| than the male larve. In fact, most of them show no sions of 
activity until March, when they begin molting for the last time 
m(Pl. IV, 2B). The white cast skins appear quite conspicuous on the 
bark. The newly molted or virgin females are smooth and of a 
-dull brown or greenish-brown color. After mating they move 
about and settle cea for the last time, most of ‘hen selecting the 
lower side of the larger limbs and branches. They soon take on a 
3 grayer appearance and begin to form waxy fringes of cotton or 
_ semicocoons about the margins of their bodies. By the middle of 
© May they have about completed their semicocoons and are full. 
grown, ready to begin oviposition. Egg laying lasts for several 
~ months, or until about the middle of ‘August. During this time 
_ the females have ‘slowly shriveled and die upon completing ovi- 
position. 
Soon after molting to the third stage thé females begin excret- 
_ ing honeydew, and do not stop until egg laying is completed. This 
_ drops onto the foliage and the ground beneath, making the trees 
and ground very sticky. A black smut fungus grows in this sticky 
material, giving the foliage a black appearance which can be seen 
for erat distances. 
SEASONAL HISTORY. 
There is orly one generation a year of the European elm scale. 
The second- stage male and female larve are the forms hibernating. 
Late in January in the milder climates a few of the male larve 
start forming cocoons in which to pupate. These become more 
abundant during February and March. Adult males begin emerging 
from their cocoons in February, becoming more abundant in March 
and April. A few of the last to transform emerge in May. 
The hibernating female larve molt for the last time in March 
and April, whereupon they move to a proper place for the summer 
and mate. They soon begin to increase considerably in size, at 
the same time forming waxy semicocoons about their bodies. Egg 
laying starts the last of May or the first of June and continues 
through June, July, and part of August. Having completed ovi- 
position the females shrivel and die. 
The eggs hatch in less than an hour after being deposited and the 
tiny yellow larve crawl about, some setthng on the twigs and 
branches, but most of them settling along the midribs of the leaves. 
About the middle of July the first of these larve molt for the first 
time, becoming reddish brown and later gray from the sugary 
particles of wax which are secreted over the back. The last of the 
yellow larve> molt early in September. ‘These second-stage brown 
or gray larve are the overwintering forms, and are found mostly 
clustered about the winter buds and in the rough areas of the twigs 
and branches. 
A definite relationship has been observed between the activity of 
- the European elm scale and its host. As the events in the life cycle 
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