MAINE AGRICULTURAL EXPERIMENT STATION. 35 



and burned. Cocoons of the tussock not covered with eggs 

 should not be disturbed as they are either the empty cocoons of 

 males or cocoons containing parasites. If the cocoons are empty 

 they can do no harm and if they contain parasites, these insect 

 enemies of the tussock should be allowed to develop. 



The fact that the females cannot fly makes this pest easily 

 controlled locally, for the orchardist need not especially fear his 

 neighbor's infested trees. 



The caterpillars are susceptible to arsenical sprays and this 

 means of combating them is sometimes necessary where the 

 winter collecting has been neglected or when the tussocks appear 

 in destructive numbers upon shade trees. 



Forest Tent Caterpillar. 

 {Malacosoma disstria.) 



The eggs of this insect are deposited in a belt encircling a 

 small twig, about 200 in each mass. These egg masses resemble 

 those of the orchard tent caterpillar, except that they are more 

 nearly square at the ends. A glistening varnish-like protective 

 substance is deposited with the eggs which renders the mass 

 more readily seen in the sun. 



The colonies of young larvae do not construct tents a"s 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 

 attached 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. 



