1906.] PUBLIC DOCUMENT No. 73. 147 



dangerous conditions of 1889 not only obtained again in 

 parts of Medford, but in addition in scores of other localities 

 in Maiden, Melrose, Saugus, Arlington, Stoneham, Behnont, 

 Winchester, Woburn and Cambridge. Beginning in 1903 

 and continuing with increasing force through 1904 and into 

 the summer of 1905, the unchecked distribution of the gypsy 

 moths from these centres into new sections w r ent on ; so that 

 when the approximate limits of the territory occupied by 

 them since 1900 had been determined by the State field work 

 of the summer and fall of 1905, it was found that their habitat 

 in eastern Massachusetts had increased in area over six-fold. 

 It was also found that the moths had entered New Hampshire 

 from Essex County, Massachusetts, and had obtained a foot- 

 hold at least as far north as Portsmouth, a notable centre 

 of travel during the Peace Conference the past summer. 

 History had repeated itself. As in 1891 it was learned that 

 the moths had become widely distributed in the years 1888, 

 1889 and 1890, so in 1905 it became plain that the second 

 ;reat unchecked distribution had 'oue on during 1903, 1904 



c cr c 



and 1905. In the extensive, newly infested area discovered 

 by our inspectors it is undoubted that there was little infesta- 

 tion prior to 1900 (with the exception of the sporadic colony 

 in Georgetown), which indicates that the diffusive energy 

 developed in the old infested district after the abandonment 

 of work there had been sufficient to infest, chiefly in three 

 years' time, a Avide area of new outlying territory. 



In accounting for this alarming spread of the gypsy moth 

 in comparatively so short a time, a new factor in the prob- 

 lem of distribution, in addition to the increase in the number 

 of badly infested centres of diffusion, has to be considered - 

 namely, the automobile. The horseless carriage must be 

 held specially accountable for the presence of the gypsy 

 moth to-day in so many remote or out-of-the-way localities 

 in the territory infested within the last five years. In the 

 second great distribution of the gypsy moth in 1903-05, 

 the regular and constant traffic over the road, together with 

 pleasure driving, continued as before the chief factor. But 

 this, being so largely of a business nature, did not extend 

 far out from the badly infested centres in the old moth terri- 



