Il8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL.84 



parasites imported from Europe, that it has ceased to be considered 

 as a pest of the first importance. 



The operations against these two insects, and especially the gipsy 

 moth, constituted the largest and most continuously active work sup- 

 ported by legislative appropriations that the country had yet experi- 

 enced. The cotton boll weevil work differed in the fact that the 

 invaded States can hardly be said to have done their share financially, 

 at least in comparison with the New England and bordering States. 



The gipsy moth work has accomplished several notable things in 

 addition to what in itself may be termed more or less of a feat, 

 namely keeping it all this time practically within the borders of the 

 New England States. These other things are, first a striking im- 

 provement in insecticides. The old Paris green, upon which farmers 

 and fruit-growers had relied during the latter, part of the last cen- 

 tury, was found, in the ordinary solutions, to be ineffective against 

 the gipsy moth. The vigorous cater])illars of this species, it was 

 found, can consume with impunity almost ten times the quantity of 

 arsenic that would kill any other caterpillar against which it had been 

 used, and larger pro]x)rtions of arsenic could not be used since the 

 burning of foliage would result. Therefore, in the course of the work 

 of chemists em])loyed by the State of Massachusetts, arsenate of 

 lead was found to be efifective and not injurious to foliage. And this 

 substance has been used by the thousands of tons not only in work 

 against the gipsy moth but in orchard work against the codling moth 

 and many other insects. 



The second result of the gipsy moth work was the enormous 

 improvement of spraying machinery. In the spraying of tall trees, 

 spray nozzles were soon abandoned, and solid-stream nozzles sub- 

 stituted. The stream of poisoned water thrown up with great force 

 from the powerful machine breaks into the requisite spray long 

 before it reaches the tops of tall trees. All of the features of the 

 machines and of the hose were greatly improved, and it has of late 

 been one of the marvels of applied entomology to see a spraying 

 machine by the roadside in the mountainous regions of southern New 

 Hampshire getting its supply of water from a roadside stream, and. 

 through strong sectioned hose carried up over the top of hills of con- 

 siderable size, spraying the trees on the other side of the hill, j)er- 

 haps nearly a mile away. 



In the course of the gipsy moth work, entomologists found them- 

 selves able to carry out on a very large scale and for continuous years 

 the importation of ])arasites of the gipsy moth and the brown-tail 

 moth from Europe and from Japan. The funds at their disposal 



