L38 (iVPSY AND BROWN-TAIL MOTHS. [Jan. 



Agricultural College. All this material is now being put in 

 order by Mr. Frederick B. Lowe, formerly of the British Mu- 

 seum, London, and now assistant at our entomological labora- 

 tory. When this work is finished we shall have a very complete 

 collection of all common injurious insects of this region, which 

 at all times will be available for the information and assistance 

 of the public. 



SPKAYIXG OPERATIONS. 



Appreciating fully the value of spraying as a means for con- 

 trolling the gypsy and brown-tail moths, the superintendent 

 f rn i the beginning of the present work has constantly urged, as 

 far as funds permitted, the purchase and use of spraying outfits 

 by the cities and towns most generally infested. Financial con- 

 siderations have prevented the buying, in any one year, of all 

 the outfits needed in the most severely infested municipalities; 

 there has been, however, a steady increase in the number of 

 sprayers, and during the summer of 1907 there were operated 

 in the field 54 po\\vr H>r;-,yers and -">^ band outfits. This does not 

 include a very large number of sprayers owned by private citi- 

 zens. The umiMia] dnmglit made it possible to continue the use 

 of the sprayer- throughout ihe caterpillar season with but Alight 

 interruption becau-e of vain. Xntable improvements have been 

 made by the manufacturers of power-spraying outfits, and, while 

 ih ere is still much room for improvement, the machines gave 

 more satisfactory results in 1907 than in any previous year. 

 The prepared arsenate of lead, or disparene, secured fresh from 

 the manufacturers, fully upheld its reputation as an effective 

 insecticide. 



Two systems of spraying were used, that of the mist spray 

 from Vermorel nozzles, used principally in orchards, on shrub- 

 bery and along roadsides, and the solid-stream spray from 

 straight-bore nozzles on shade trees and in woodland. With the 

 fir-t system of spraying, a pressure of from 7.". to 100 pounds 

 1o ihe square inch is sufficient : with the second, a pressure of 

 from 1:10 to 200 pounds is desirable, the high pressure causing 

 ihe >hvani to break into a mist at a considerable distance from 







the no/xle. The n -nils obtained practically confirm our pn- 

 vioUS opinion in regard to the two systems of spraying, each of 

 which ha~ ils champions. As usual, the mist spray gave the 



