INSECTS AFFECTING OHIO SHADE TREES 18* 



larly of limbs and fence rails. The nearly globular, pale yellowish 

 or salmon-colored egg's are about one-twentieth of an inch in diam- 

 eter, and there are usually 400 to 500 eggs in a cluster, though oc- 

 casionally 1000 may be found in an egg mass. 



"The young caterpillar is slightly over one-tenth of an inch 

 long just after it emerges from the egg. It has a black head, the 

 body is brownish yellow and well clothed with long hairs. There is 

 a prominent hairy tubercle on either side of the segment next the 

 head; this gives the caterpillar a peculiar broad-headed appearance, 

 especially in its early stages. The markings become plainer as it 

 increases in size, and when full grown it is from 2 to 2>^ inches 

 long. This caterpillar has a double row of conspicuous warts or 

 tubercles down its back, the eight anterior blue, the 12 remaining 

 red, not counting the four blue ones iust behind the head. Similar 

 tubercles also occur on the sides. 



"The somewhat conical, dark brown pupa ranges from 24 to 

 1>2 inches long. It is usually found lying among a few threads and 

 securely attached to them by its terminal spine. 



''The male and female moths differ markedly. The former, a 

 slender, olive brown, black-marked creature with feather-like anten- 

 nae and having a wing spread of about 1> inches, may be seen flying 

 in the late afternoon and early evening in considerable numbers. 

 The female is much heavier and lighter colored. She has a wing 

 spread of about 2 inches and is a white or buff white color with more 

 or less distinct black markings. The abdomen is tipped with buff. 

 The female moth does not fly though she apparently has well de- 

 veloped wings. 



"The winter is passed in the egg-mass, which is remarkably 

 resistant to atmospheric and other agencies. Experiments have 

 shown that even when the egg clusters were broken up and freely 

 exposed to the elements, the eggs were apparently not harmed, and a 

 normal proportion of the caterpillars appeared at the usual time, 

 which, in the vicinity of Boston, is from the last of April until the 

 middle of June. The feeding period extends from the first of May to 

 about the middle of July, a caterpillar requiring from about 9 to 11 

 weeks to complete its growth and enter the pupal stage. The young 

 caterpillars remain on the egg clusters from one to five or more days 

 and then commence feeding on the leaf hairs. Soon they eat out 

 small holes in the leaves and, after the third or fourth molt, about 

 as many feed on the edge of the leaf as eat out holes. The cater- 

 pillars are largely nocturnal, remaining in clusters on limbs and 

 trunk, or hiding in some crevice during the day, and beginning be- 

 tween 7 and 8 o'clock in the evening leisurely to ascend the tree, 

 where they feed on the foliage at intervals during the night, descend- 

 ing about 3 o'clock in the morning. 



