DISTRIBUTION BY MAN. 107 



over the road. Inquiries were first made in the inner and 

 worst infested towns. Supplementary and additional infor- 

 mation was gathered later outside the infested district in those 

 localities known to have had more or less communication with 

 the " danger tract" of the infested region during the greatest 

 prevalence of the moth. This ' ' danger tract" was the heart of 

 the infested region (Medford and Maiden) because the swarm- 

 ing numbers of the caterpillars there had made possible their 

 frequent transportation by vehicles to other points. At first 

 there was not so much danger of such transportation from 

 anywhere else in the infested district because of the com- 

 parative scarcity of the moths in other localities and the 

 usual small size of their colonies. This study shed a flood 

 of light upon the manner of the distribution of the moths in 

 the territory originally infested from Medford, and explained 

 the existence of many colonies in woods and other retired 

 places. It also indicated the places which had been most 

 exposed to infestation in the territory lying beyond the 

 known limits of the moth's spread. 



The investigation of the transportation of the moth was 

 confined mainly to the traffic and communication to the north, 

 east and west of Medford. The great bulk of all driving over 

 the road and the still greater proportion of ' ' dangerous " or 

 constant traffic was to the north and west and along the 

 North Shore to the north-east, and consequently the moth 

 had been diffused farther in those directions. There is little 

 constant and direct teaming traffic to any other southern 

 point than Boston, and the latter place, by reason of the 

 small number of trees in its business sections, was a com- 

 paratively safe point for the reception of such traffic. 



In the inquiry in regard to the traffic over the road, all 

 information possible was obtained concerning the routes of 

 expressmen and movers, market-gardeners, farmers, milk, 

 hay and wood dealers, swill-takers, butchers, peddlers and 

 junk men. Local boards of health and milk inspectors in 

 and around Boston furnished information by means of which 

 those engaged in the milk business and in swill taking were 

 located and their routes ascertained. Much information was 

 secured in regard to the great market-gardeners' traffic over 

 the road between Boston and towns within the infested district 



