122 THE REPORT OF THE No. 19 



Chief of tlie Bureau of Entomology conveying this information, and attempts 

 have been made by mail and otherwise to send these parasites to the United 

 States, but without success. Later information received from one of the 

 most skilled economic entomologists of Japan, Mr. Nawa, indicated that 

 there exists in Japan an important egg-parasite of the gipsy moth. Remem- 

 bering that the Massachusetts gipsy moth came originally from Europe it 

 seemed altogether desirable to introduce first the European parasites, and 

 it seemed probable that these would by themselves reestablish the balance of 

 nature. Then too, the importation of the Japanese species seemed somewhat 

 dangerous, on account of the chance that the Japanese Gipsy moth might prove 

 even more voracious and destructive than the European moth; but, after 

 consideration, it was thought best to leave no stone unturned and to neglect 

 no chances in the search for effective parasites. The European service of 

 collectors and agents and advisers had been well organized and instructed 

 during three annual visits of the Chief of the Bureau to Europe, and it was 

 therefore decided to interrupt the European trip for the present year and 

 to send an agent to Japan. Professor Trevor Kincaid, of the University o"? 

 Washington at Seattle, was chosen on account of his skill as a collector, h's 

 comparative proximity to Japan, and the fact that he is personally acquainted 

 with many persons in Japan. He sailed on the 2nd of March, and the results 

 of the expedition have more than justified the expense involved. A very 

 large amount of parasitic material has been received from him in good 

 condition at Boston, and very many parasites from Japan have been col- 

 onized in the woodlands of New England. 



Still another decided innovation has been the carrying on of active 

 winter work with parasites, especially those secured from imported nests 

 of the brown-tail moth which began to come in from Europe in December. 

 It was found quite possible to breed these parasites in artificially heated 

 rooms, feeding them upon hibernating native brown-tail moth larvse brought 

 in in their nests from out of doors, feeding the latter upon lettuce and other 

 hothouse foliage and in the early spring securing more normal food for 

 them by sending it up in boxes by mail from Washington and points south. 

 In this way the breeding of the parasites of the genus Pteromalus was car- 

 ried forward uninterruptedly throughout the winter, and, as during the 

 breeding of successive generations they multiplied exceedingly, it was pos- 

 sible later in the year to liberate a vastly greater number of individuals 

 than would have been possible had the imported species been allowed to 

 hibernate normally in the nests. In the course of this work Mr. W. F. Fiske, 

 in charge of the breeding operations, has invented a rearing tray which 

 has been of the utmost advantage and which will greatly facilitate parasite 

 rearing work in the future. 



Still a fifth innovation and one of great value has been the discovery 

 and practice of retarding the development of brown-tail moth eggs by keep- 

 ing them in cold storage until the arrival of the European egg-parasites 

 which will oviposit upon and breed in these cold storage eggs as freely as 

 those which they attack in the state of nature. This process it has been 

 ascertained may be carried on for a long time, and successive generations 

 of these egg-parasites may be reared from eggs retarded in their develop- 

 ment by cold storage. It is thus easy to breed and to liberate an almost 

 infinitely greater number of these egg-parasites, and under favourable con- 

 ditions, than would be possible from a simple importation of European 

 parasitized eggs which would have to arrive in America at a specific time. 

 These latter innovations have been due to the ingenuity of Mr. Eiske to 

 w^om great praise should be given. 



9a EN. 



