168 SHADE-TREES IN TOWNS AND CITIES 



winter in a sort of half-dormant condition. They become 

 active again about the middle of April, or with the opening 

 out of new foliage, and feed upon the buds and the unfold- 

 ing leaves. They feed until June, when they spin an open 

 cocoon of coarse silk among the leaves, and transform to 

 pupae. A month later the moths emerge to begin the life 

 cycle again. 



The brown tail moth attacks a great variety of both wild 

 and cultivated plants, especially the oaks, maples, and elms. 

 One of the ways of combating this species is by removing 

 and burning the hibernating nests which are very con- 

 spicuous during the winter and in the spring. Spraying 

 with arsenate of lead, both when the foliage develops and 

 when the young caterpillars hatch, is also very effective. 



Fall Web worm {Hyphantria cunea Dru.) . The presence 

 of this insect can be readily discovered by the large tents 

 formed by the caterpillars. The first brood is rarely abun- 

 dant enough to attract attention, and the nests seem to be 

 smaller than those found later in the season. Early in July 

 the caterpillars are full grown, leave the nests and make 

 cocoons in any convenient shelter near by, in crevices of the 

 bark or on the surface of the ground. Moths issue in a few 

 days and shortly afterward are ready to lay eggs in turn. 



When the second brood appears in July, or early in 

 August, the tents are so much more numerous that they 

 attract more attention, and the insects grow so fast that 

 unless measures are taken at once, the infested trees may 

 suffer defoliation. Late in August and during the first half 

 of September, the larvae of the second brood leave the nests 

 and wander to some shelter where they change to the pupal 

 state and remain in that condition all winter. 



The caterpillar of the fall webworm is a general feeder 



