20 BULLETIN 273, U. S. DEPARTMENT OP AGKICULTUKE. 



north 17, from the northeast 22, from the east 3, from the southeast 

 51, from the south 37, from the southwest 1, and from the west 9 

 hours during the foregoing period. In Amherst, Mass., it blew for the 

 same period from the northwest 50 hours, from the north 51, from 

 the northeast 9, from the east 2, from the southeast 30, from the south 

 31, from the southwest 3, and from the west 46 hours. 



Providence was first found infested by the gipsy moth in 1901, 

 and during the scouting season of 1913-14 egg clusters were found 

 as far west as Woodstock, Pomfret, and Brooklyn, Conn. — a distance 

 of 36 miles, or an average spread of 3 miles each year. It is apparent 

 that this general infestation was not accomplished by direct east 

 winds, as there are few recorded each year at the proper period, but 

 by a combination of northeast and southeast winds transporting the 

 larvse hi a southwesterly and northwesterly direction from 1 to 10 

 miles, thus gaining an average of 3 miles each year directly west. 



Although this insect has not yet reached Amherst, Mass., in its 

 general sweep across the country, it occurs within a few miles to the 

 eastward. A perusal of the wind records for the dispersion period 

 of 1913 shows three times as many hours of north winds and about 

 one-half as many northeast and southeast winds combined as are 

 recorded in Providence, R. I. The total movement of northwest 

 and west winds, which blow the larvae back into the infested terri- 

 tory each year, is practically the same in the two localities. 



From this data it appears that the increase in the amount of north 

 winds and the decrease hi combined northeast and southeast winds 

 at Amherst, when compared with the wind records at Providence, 

 may result in a somewhat more rapid southwestern advance of the 

 insect if it becomes established in the Connecticut Valley. More 

 rapid southern and western spread is likely if the infestation reaches 

 the Central States. 



SPREAD OF THE GIPSY MOTH IN NEW ENGLAND. 



The gipsy moth was introduced at Medford, Mass. (PL VII), in 1869, 

 from which point it has spread gradually over large areas in Massa- 

 chusetts and other New England States, excepting Vermont. 1 Small 

 infestations have also been located in New York, New Jersey, and 

 Ohio, but these colonies are fast being exterminated. Extensive 

 efforts to prevent spread have been carried on in Massachusetts by 

 the State since 1890, with suspension of appropriations and efforts 

 only from 1900 to 1905. Other infested States have appropriated 

 smaller amounts which have aided in the suppression work. Con- 

 gress began making appropriations in 1906, and these annual sums 

 have been expended to prevent spread and help control of the gipsy 

 moth and the brown-tail moth. 



1 See, however, footnote on p. 17. 



