164 SHADE-TREES IN TOWNS AND CITIES 



molts. When they complete their feeding period, nothing 

 but the principal veins of the leaves are left. 



The larval period lasts about four or five weeks. Then 

 the caterpillars return to the bark, spin cocoons and change 

 to pupae. They remain in that condition for two weeks and 

 then emerge as adults. The males are winged and the 

 females wingless. Pairing now takes place, the males die 

 and the females deposit a cluster of eggs for the second 

 brood. Generally from three hundred to five hundred eggs 

 are found in a single cluster, from which if conditions are 

 favorable, as many caterpillars may hatch. 



The summer, however, is but half over. Toward the 

 end of July, and the beginning of August, the eggs deposited 

 by the first brood hatch and the young larvae go up on the 

 leaves to finish the work begun by the parents. The cycle 

 continues as before— through the larval, pupal, and the adult 

 condition. In September the eggs are deposited on the bark 

 of the trees, remain in that condition through the winter, 

 and hatch in the spring. 



The easiest and most effective means to control this in- 

 sect is to exterminate it while it is in its egg condition. The 

 clusters are loosely attached to the bark, are very conspicu- 

 ous, and are mostly on the trunks and lower limbs. They 

 can be removed either by hand or by scraping them off. 

 After collecting, the egg masses should be burned. 



If the eggs are allowed to hatch, the only treatment then 

 possible is to spray the foliage of the tree with a solution of 

 arsenate of lead. (See Insecticides, Chap. IX. ) The method 

 of spraying is not always so thorough as removing the egg 

 clusters. 



During the last four years, very little spraying has been 

 done in East Orange to control the tussock moth. In spite 



