October, '14] FELT: FOREST INSECTS 373 



moth is changing or has changed its habits in this country. Sixteen 

 or seventeen years ago, when the Report on the Gipsy Moth was 

 published by Forbush and Fernald, elm and barberry and many other 

 trees and shrubs were considered very favorable food plants. In 

 obscure locations where a slight infestation was detected and barberry 

 was present the egg masses were usually found on that species, but 

 this is seldom the case today, and this shrub is rarely infested. That 

 the insect itself is less hardy than in the past is a surety and it is far 

 more susceptible to disease. Again, there is a perceptible decrease 

 in the average number of eggs laid by female moths except in newly 

 infested territory, and as a rule full-grown larvse secured at the 

 present time are seldom as large as specimens taken at the time the 

 above-mentioned report was published. These conditions may have 

 some bearing on the results secured in our investigations from those 

 published fifteen years ago. 



NOTES ON FOREST INSECTS 



By E. P. Felt, Albany, N. Y. 



Both 1912 and 1913 were remarkable because of the abundance of 

 the forest tent caterpillar, Malacosoma disstria Hubn. Last season 

 it stripped oaks on Long Island, sugar maples in the Hudson and St. 

 I^awrence valleys, and in certain Adirondack sections extensive areas 

 of poplar were defoliated, a marked preference being shown for the 

 tops of the taller trees. Pin or bird cherry, cornus and elms were 

 partly stripped when near defoliated poplars, while red maple, birch, 

 pine, balsam, spruce and hemlock were practically untouched. This 

 is the second outbreak of the forest tent caterpillar in fifteen years, 

 and in each instance there has been a superabundance of the apple 

 tent caterpillar, Malacosoma americana Fabr. These species are so 

 closely allied and are preyed upon to so large an extent by the same 

 natural enemies, that it seems reasonable to expect synchronous out- 

 breaks. We are of the opinion that insect parasites of the larvse are 

 among the more important controlling agents, though the increase 

 in New York State, of injuries by leaf-feeding caterpillars in recent 

 years suggests that the observed r.eduction in bird life during the past 

 two decades may also have an important bearing on the problem. 



The territory in the immediate vicinity of New York City has 

 suffered greatly from the activity of a number of borers. The spotted 

 hemlock borer, Melanophila fulvoguttata Harr., has destroyed many 

 highly valued hemlocks; the two-lined chestnut borer, Agrilus bili- 

 neatus Weber, is killing the oaks, while the hickory bark beetle. 



