FOREST INSECTS AND FUNGI 113 



but identification is easiest by the discovery of the large egg 

 masses which are oval in shape, about an inch wide and two 

 inches long, of a buff color and presenting much the appearance 

 of a piece of sponge. These may be found on the bark of trees 

 or under leaves on the ground. The young caterpillar is about 

 one- tenth inch long on emerging from the egg; when full grown it 

 is from two to two and a half inches in length. It has a double 

 row of tubercles down the back, eight blue and twelve red. 

 The pupa is dark brown and from three-fourths to one and a 

 half inches long. The male and the female moth differ widely 

 in appearance. The former is small and of a brown color, with 

 a wing spread of one and a half inches. The female, of a white 

 or buff color, and with a wing spread of about two inches, is 

 too heavy to fly. 



Life History. In this country as well as in Europe this 

 insect has but one generation a year. The minute eggs are laid 

 in clusters of from four hundred to five hundred eggs each. 

 Yellowish hairs give to these clusters a sponge-like appearance, 

 and although they are usually on the trunk of the tree, or the 

 side of a log, they are often concealed in crevices and under 

 rocks. Eggs are laid in the latter part of the summer and 

 usually do not hatch into caterpillars until the following spring, 

 from the end of April until the middle of June. The cater- 

 pillars reach full growth in about ten days, spin filmy cocoons 

 usually on the trunks of trees, and finally emerge as moths in 

 late July or August. Most of the damage is done in the cater- 

 pillar stage, and the dissemination of the insect is also due 

 largely to the activity of the caterpillar. Eggs and caterpillars 

 are distributed by artificial means, as on cars, automobiles, etc. 



Treatment. The conspicuous color of the egg mass and the 

 long duration of the insect in this stage make this the most 

 vulnerable stage to combat. The masses may be collected and 

 burned, or, as is most generally done now, they may be treated 

 with a coating of creosote. In the woods, extreme vigilance is 

 necessary to find these clusters. All brush, especially near stone 

 walls, should first be removed. 



