70 THE BROWN-TAIL :SIOTH. 



237 webs on elm : — 



April 26, 101 webs yielded larvjB. 



April 27. . . . . . 10 webs yielded larva}. 



April 28, 12 webs yielded larvas. 



April 29, - w'ebs yielded larvas. 



April 30, 3 webs yielded larvae. 



126, or 53 per cent. 



These figures show clearl}- that full spraying is not an 

 extcrniinative method, probably for the reason that some 

 of the insects enter the webs earl}' to hibernate. It is also 

 \ery interesting to notice the dift'erence in the effectiveness 

 in the spra3dng of large and small trees. The pear trees 

 were easily reached by ladders, and thoroughly sprayed. 

 On .the large elms thorough work was also attempted and 

 umch time and lalx)r spent in spraying them, but the results 

 were only one-fourth as satisfactory. These figm'es also 

 have a wider siirnificance, in showino- us how difficult it is 

 to get entirely satisfactory results in spraying large trees. 



Municipal "Work. 



Tlie advent of the brown-tail moth in Massachusetts and 

 its gi-adual distribution in thickly settled districts gives 

 another excellent ilkistration of the interdependence of all 

 citizens in a community where matters of public good are 

 at stake. Where the moth occurs but scattoringly, its 

 ravages arc slight und the pest is easily controlled. The 

 case is far (litlcrcnt, however, when the insect is numerous; 

 one single pear or :ij)i)le tree on an estate may carry from 

 one to two hundred webs, each web containino:, on the 

 average, two hundred and fifty cateri)illars. The insect 

 spreads readily in the taller .shade trees, from which it can 

 only be cleared at a great expense. Even if the property 

 owner succeeds, at the outlay of nuich time and money, in 

 freeing his place from these insects, hi.s labors are unavail- 

 ing should his neighl)or, through ignorance or carelessness, 

 allow the trees on his estate to remain badly infested. 



A\ e have .seen repcatedlv in the metropolitan district 

 numerous illustrations of the annoyance and damage thus 

 caused by the neglect of one property owner to clear his 



