124 THE BROWN-TAIL MOTH 



comes next and, owing to its abundance, is the tree upon 

 which the webs are first most commonly found in a newly 

 infested section. All of the fruit trees and of the shade 

 trees, elm, oak and maple, are freely attacked, in fact, 

 almost all fruit, shade and forest trees, except the pines, 

 spruces and other conifers are attacked in a badly infested 

 district. Injury to woodlands and forests does not seem 

 to be as serious as that inflicted by the gypsy moth, though 

 often the defoliation is sufficient to cause large tracts to 

 appear brown and seared. As yet, woodlands have not 

 been infested sufficiently for a time long enough to definitely 

 determine just how serious the constant total or partial 

 defoliation by the brown-tail caterpillars will be. It is 

 well known, however, that any deciduous tree wholly defoli- 

 ated for three or four years is usually killed, and that the 

 wood growth is seriously checked by partial defoliation, so 

 that there is a distinct loss in the timber value. 



As the pest concentrates in towns, the shade and fruit 

 trees suffer most and, unless the winter webs are removed, 

 being defoliated year after j^ear, become weakened and soon 

 die. As when defoliated by cankerworms, tent-caterpillars 

 or other caterpillars, fruit trees stripped of their foliage 

 can hardly yield a crop of fruit and the control of the pest 

 upon them is therefore imperative. 



One of the most serious effects of the presence of the 

 brown-tail moth in a community is that of the peculiar 

 skin disease it may produce. Some of the hairs of the full- 

 grown caterpillars are furnished with minute barbs. When 

 the caterpillars molt these barbed hairs are shed with the 

 skin and as the skins become dry and are blown about by 

 the wind the hairs may be quite generally disseminated. 

 "When the hairs alight upon the human skin they cause an 

 irritation, which upon rubbing may develop into inflam- 

 mation. In New Hampshire this phase of the insect's pres- 



' Largely reprinted from Bulletin 107 by C. M. Weed. 



