36 PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 



The practical results of these importations seem to have been 

 excellent. There seems to be no doubt that the parasites have been 

 the controlling factor in the reduction of the leafhoppers. 



The good work in Hawaii is still continuing. Koebele is now on a 

 visit to Europe to import the possible parasites of the horn fly 

 (Hsematobia serrata Rob.-Desv.), Muir is trying to find an enemy to 

 a sugar-cane borer (Rhabdo mentis obscurus Boisd.), and other similar 

 work is under' way. 



An Importation of Clerus from Germany. 



An early attempt to import beneficial species into the United 

 States was made in 1892 by Dr. A. D. Hopkins, then entomologist 

 to the West Virginia Agricultural Experiment Station and now of 

 the Bureau of Entomology. A destructive barkbeetle, Dendroc- 

 tonus frontalis Zimm., was extremely injurious in that State in the 

 years 1889 to 1892, and Hopkins made the effort to import from 

 Europe another beetle, (Clerus) Thanasimus formicarius L., from 

 Germany. In Germany he collected more than a thousand specimens 

 of the Clerus, which he took with him to West Virginia and distrib- 

 uted in various localities infested by the barkbeetle. The following 

 year, however, the barkbeetle disappeared almost completely from 

 other causes, and the Clerus has not since been found. 



Marlatt's Journey for Enemies of the San Jose Scale. 



Another and later expedition was that undertaken by Mr. C. L. 

 Marlatt, of the Bureau of Entomology, in search of the natural 

 enemies of the San Jose scale. The question of the original home 

 of the San Jose scale (Aspidiotus perniciosus Comst.) had been a 

 mooted point. As is well known, it started in this country in the 

 vicinity of San Jose, Cal., in the orchard of Mr. James Lick, who had 

 imported trees and shrubs from many foreign countries. Mr. Lick 

 died before the investigation started, and no records of his impor- 

 tations were to be found. The scale was not of European origin,' 

 since it does not occur on the continent. In the course of investiga- 

 tion it was found that it occurred in the Hawaiian Islands, in Japan, 

 and in Australia, but in the case of Australia and the Hawaiian 

 Islands it was shown that it had been carried on nursery stock from 

 California. In 1897 plants entering the port of San Francisco from 

 Japan were discovered by Mr. Craw to carry the San Jose scale. 

 Correspondence, however, seemed to point to the conclusion that it 

 had also been introduced into Japan from the United States. In 

 1901-2 Mr. Marlatt made a trip of exploration in Japan, China, and 

 other eastern countries, lasting more than a year. Six months 

 were spent in Japan, and after a thorough exploration the con- 

 clusion was reached that the scale is not a native of that country 



