MAINE AGRICULTURAL EXPERIMENT STATION. I91O. 361 



gives out they leave the web and seek other trees. Otherwise 

 they remain until they are full grown (a little more than an 

 inch in length), when they drop to the ground and seek a place 

 where they may make cocoons. Recesses which attract them 

 for this purpose are crevices in bark, spaces under boards or 

 door steps, or near the surface of the ground in rubbish. These 

 insects pupate within thin, almost transparent cocoons and re- 

 main in them all winter, emerging as mature moths in the 

 spring. 



REMEDIAL MEASURES. 



Trees well protected with arsenical sprays (Formula 6) will 

 not need other treatment for fall web worm, for the poisoned 

 leaves will be drawn into the w^eb for food. In many cases the 

 simplest means for combating them is to keep close watch upon 

 the trees and clip off and burn the web when it is still small. 

 Even the full sized web can be pruned off from trees not valu- 

 able, but in the orchard there is. of course, no excuse for allow- 

 ing them to remain until large branches are involved in the web. 

 The web may be effectually drenched with a strong washing 

 powder solution or kerosene emulsion. 



2. Orchard Tent Caterpillar. 

 (Alalacosoma americana.) 



Encircling the twig of apple, plum, and wild cherry trees is 

 frequently found a glistening brown mass about three-fourths 

 of an inch in length (fig. 36). 



From such an egg cluster hatch in the spring from two hun- 

 dred to three hundred caterpillars, which live in a colony and 

 construct a whitish tent-like web in the angle of two convenient 

 branches. It is the habit of the tent caterpillars to pass their 

 time when not feeding, particularly at night and during cold or 

 stormy weather, within the tent which they enlarge as their own 

 rapid increase in size calls for more room. During the warm 

 sunny hours of the day they leave their protection and feed 

 voraciously, defoliating the branches in the vicinity of the tents. 

 One colony is enough to denude a young tree or several large 

 branches of an old tree. 



The tent which is at first a delicate filmy silken web becomes 



