30 IMPORTED PARASITES. 



the cocoons were collected in the field in Japan until they were 

 received at the laboratory in Melrose. Events justified the 

 adoption of every precaution, and, with all the care, only a 

 small part of the very large quantity of cocoons which he col- 

 lected reached their destination in good condition. Hundreds 

 of thousands were collected and shipped, and less than 50,000 

 were received alive, — nearly all in one shipment in July. 



The season in Massachusetts was early, and nearly all of the 

 gypsy caterpillars had pupated by that time, so that there was 

 no opportunity for the parasite to increase in the field upon this 

 host that season. In 1909 the sites of the colonies were fre- 

 quently visited, but not a single parasitized caterpillar was 

 found which could be traced to colonizations of the year before. 

 Keen disappointment was at first felt, but later developments 

 have tended to throw a more encouraging light upon the situa- 

 tion. 



In 1909 importations were continued, through the magnificent 

 efforts of Prof. S. I. Kuwana of the Imperial Agricultural 

 Experiment Station, at Tokio, with much more satisfactory 

 results. In 1908 the season in Japan was very late, and it was 

 not practicable to send any of the cocoons of the parasite until 

 June and July ; while in America the season was early, and by 

 that time all of the caterpillars, as has already been stated, had 

 pupated. In 1909 the season was rather early in Japan and 

 correspondingly late in America; and besides, through special 

 effort. Professor Kuwana was enabled to send a few thousands 

 of the cocoons of the first generation, which reached the labora- 

 tory early in June. About 1,000 adults emerged from these 

 cocoons after receipt, and the most of them were placed in one 

 colony in a cold situation on the North Shore, where the cater- 

 pillars were greatly retarded, and where there were still some 

 in the first stage. The remainder were colonized in warmer 

 localities, where the caterpillars were one stage farther 

 advanced. 



Immediate success followed the planting of these colonies. 

 Within three weeks cocoons were found in each, and the number 

 of parasitized caterpillars was gratifyingly large. A very care- 

 ful investigation was conducted, to determine the proportion 

 which was attacked by native secondary parasites; and, while 

 this was so very large in one instance as seriously to jeopardize 



