MAINE AGRICULTURAL EXPERIMENT STATION. 19IO. 35 1 



The colonies of young larvae do not construct tents as do the 

 orchard tent caterpillar, but they are usually massed during 

 dark or rainy weather. 



The caterpillars resemble the orchard tent caterpillars, the 

 most striking difference being that the cream colored line along 

 the back is broken into a line of dots in the forest tent cater- 

 pillar while with the orchard tent caterpillar this line is un- 

 broken. They grow to be about two inches long. 



The full grown caterpillar constructs a filmy outer cocoon 

 with an inner firm cell which it soaks with a yellow discharge 

 drying to a pale yellow powder. These cocoons are often at- 

 tached to buildings. 



Moth — In from 10 to 14 days after spinning the cocoon the 

 adult insect emerges. This yellowish-brown moth resembles 

 that of the orchard tent caterpillar closely but the transverse 

 bands on the wings are darker than the ground work of the 

 wings instead of paler as with the other species. It is not 

 practicable to combat the insect in this stage. 



REMEDIAL MEASURES. 



Arsenical sprays (Formula 6) applied early in the season will 

 satisfactorily dispose of this pest and for orchard or shade trees 

 protected in this manner no other means are necessary. After 

 the caterpillars are half grown it is their custom to congregate 

 in great masses on the trunks of the trees while they molt their 

 skins. Here they may be destroyed by a stiff broom dipped in 

 Kerosene or swept into a pail of water and kerosene 



When not congregated for molting the older caterpillars when 

 not feeding stretch out motionless along the branches or trunk 

 and are difficult to see, especially as they are likely to choose 

 the upper side of the branch. 



However, it is not necessary to wait for the molting periods 

 in order to combat the older caterpillars on trees which have 

 not been protected by spraying. These caterpillars drop down- 

 ward when disturbed. "This habit leads to the suggestion that 

 by a combination of jarring and banding much injury may be 

 prevented." After the caterpillars are jarred from the tree the 

 trunks of trees are painted with a band of "tanglefoot" such as 

 is used against the gypsy caterpillar to prevent their ascending. 



