36 



hood when they descend from the trees to go into the 

 ground. 



The caterpillars wlien grown are black, without evident 

 markings, and are loosely clothed with soft whitish hairs. 

 "When they come down from the trees they measure 

 about two inches in length. The young caterpillars are 

 paler in color, and are distinctly striped with whitish. 

 When they leave the trees they have the singular 

 habit of collecting on the trunks near the base in 

 large masses of a hundred or more individuals. At Lex- 

 ington such masses liave been observed as early as July 

 19, these probably representing an early brood, but the 

 injury is at its worst during August, and the greater 

 number of larvte come from the trees during the last 

 half of August and the first half of September. I have 

 no record of adult moths observed between July 19 and 

 September 1, but am disposed to think there are two 

 broods every summer. 



The pupa is formed in the ground under the trees, and 

 that of the late brood remains here over winter, the moth 

 emerging during the first half of June of the following 

 spring. 



The moth is reddish brown in color, with a patch of 

 deeper brown on the thorax. The front wings, which 

 have an expanse of from 1.80 to 2.30 inches, are crossed 

 with five dark lines, the first being nearest the base, the 

 second at about the middle of the wing, and the remain- 

 ing three being close together on the outer half. The 

 fourth line is fainter than the others and is very close to- 

 the fifth. The region between the first and second is 

 darker than other parts of the surface and bears a black 

 dot near the front edge of the wing. The moth is much 

 like that of the next species, but its wings are less uni- 

 form in color and the cross lines are accompanied with 

 rather wide but obscurely outlined pale bands. 



Besides walnut the species is said to attack willow. 



