GYPSY AND BROWN-TAIL MOTHS. 31 



the success of the experiment, it was not so large in the 

 others. 



There were several thousands of this first generation known 

 to have developed in the open upon American soil, which issued 

 from the cocoons some four or five weeks after the colonies were 

 established, but in only that one on the North Shore, where the 

 caterpillars were in the first and second stages when the parasites 

 were liberated, was there a full second generation. Here the 

 larger caterpillars were again attacked, and an abundant second 

 generation of the parasite followed. 



Meanwhile, additional shipments of cocoons of the second 

 Japanese generation were received early enough to permit of 

 a generation in the open upon the native caterpillars, and sev- 

 eral other colonies were successfully established. It is known 

 that there were many thousands of the parasite issuing in at 

 least five diiierent localities during August, but immediately 

 thereafter they were completely lost to sight, and it is futile to 

 hope to recover traces of them before another spring. 



Until the late summer of 1909 nothing occurred to indicate 

 that this parasite would be likely to fly for any great distance 

 from the point of its liberation ; and, as has been already stated, 

 it was looked for in vain in the summer of 1909 in the imme- 

 diate vicinity of the colonies of the year before. In July, 1909, 

 a strong colony was planted in an isolated woodland colony of 

 gypsy moths in the town of Milton. It was rather confidently 

 expected that it would attack these caterpillars so extensively 

 as to destroy the major portion ; but it was the cause of some 

 surprise, when the locality was visited after the parasites of the 

 new generation had mostly issued from the affected caterpillars, 

 to find a smaller number of cocoons than there were individuals 

 liberated in the first place, and only about one-fourth, perhaps 

 less, of the caterpillars attacked. The circumstance was as dis- 

 couraging as anything which had gone before, and for a few 

 days nothing happened to change its complexion. Then, to the 

 intense surprise of the writer, Mr. Charles W. Minott, field 

 agent of the central division, sent to the laboratory a horn-fide 

 example of the parasite, which had been collected in the Blue 

 Hills reservation, upwards of a mile away. There was no pos- 

 sible source except the Milton colony, and a spread of upwards 

 of a mile in something under a week was indicated beyond dis- 



