50 BULLETIN 1103, U. S. DEPARTMENT OF AGRICULTURE. 



tures during the winter months. Extreme low temperatures are 

 known to be fatal to the egg clusters that are deposited in exposed 

 situations above the snow line. 



The species is considered as a serious pest over the whole area of 

 its distribution, although the actual damage to the foliage of trees 

 in the area between the outer and inner lines on the map (Fig. 27) 

 is but slight, and has been classified in the records of the gipsy moth 

 laboratory as lightly infested, as is also the area in New Jersey. The 

 area inclosed by the inner line on the map is classified as generally 

 infested. It could not be said that the species Avas numerous enough 

 in 1921 in all parts of this area actually to cause damage to the trees, 

 but over the greater part of this area numerous defoliations occurred 

 to forest, shade, and fruit trees, and over a considerable portion of 

 this area complete defoliation involving extensive areas occurred. 



During 1920 an infestation was discovered in northern New Jersey. 

 This infestation now covers the greater part of Somerset County; 

 Readington Township and east Amwell Township in Hunterdon 

 County; and Middlesex County with the exception of the townships 

 of Monroe, Madison, and Woodbridge. In Union County the insect 

 has spread into the western corner covering Plainfield Township. 

 An isolated infestation has also been located in Tewksberry Town- 

 ship in Hunterdon County. 



BROWN-TAIL MOTH. 



( Euproctis chrysorrhoea L.)" 



The innermost line on the distribution map (Fig. 28) of the 

 brown-tail moth indicates the area that was generally infested dur- 

 ing 1921 ; although the pest could not be considered as serious 

 throughout this entire area, it caused appreciable damage to fruit 

 trees, and in several localities was so abundant that many apple and 

 pear orchards were completely defoliated. The area between this 

 line and the intermediate line on the map was slightly infested, the 

 intermediate line bounding the area known to have been infested 

 during the season 1921. It will be noted that this pest has materially 

 receded from its maximum area of infestation attained in 1914, 

 indicated on the map by the outermost line. 



Arthur Gibson, Dominion Entomologist, sa3^s : 



This insect is being kept under control by the collection of the winter nests 

 in the Provinces of Nova Scotia and New Brunswick, the only two provinces 

 in Canada where this pest has gained a foothold. Practically no damage by 

 the caterpillars has been effected under orchard conditions. 



In the advance of this species to the north and northeast, conditions 

 rapidly change with reference to its food plants. The pear, one of its 



'3 By A. F. Burgess, Bureau of Entomology. 



