288 PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 



tail moth imported in hibernating nests, and these methods applied 

 equally well to Meteorus. It was not nearly so common as the Apan- 

 teles, and only about 1,000 adults were secured for colonization. 

 These were all liberated in one colony at a convenient place from 

 the laboratory, and in order that they might have an opportunity 

 for immediate reproduction a very large number of retarded cater- 

 pillars of the brown-tail moth from nests which had been placed in 

 cold storage during the winter were liberated upon trees in the 

 immediate vicinity. 



These caterpillars seemed to be not at all injured as a result of their 

 abnormal experience, but immediately began to feed voraciously and 

 to grow apace. That they were injured soon became evident, but it 

 could not be determined whether such injury was due to the enforced 

 lengthening of their period of hibernation, to the hot weather which 

 then prevailed, or, possibly, to the fact that the foliage was much 

 more advanced than that upon which caterpillars newly emerged from 

 hibernation usually fed. They began to die at an alarming rate 

 inside of two weeks, and when it was time to make a collection for the 

 purpose of determining whether the Meteorus had found them or not 

 hardly more than 300 could be found out of the thousands which had 

 been liberated. These were removed to a tray in the laboratory, and 

 from June 23 to July 15 no less than 76 Meteorus cocoons were 

 removed. From these 43 adults, of which 16 were females, were 

 reared. 



These were the first females of the second generation which had 

 been secured at the laboratory, and a part of them was used in a 

 reproduction experiment similar to those which had resulted in the 

 production of males the previous year. Curiously enough, the adults 

 of the third generation reared from these parents, under circumstances 

 identical with those which had been used in earlier reproduction 

 experiments, consisted of both sexes, there being 5 females out of a 

 total of 40. These were the first females of the species ever reared 

 from adults in confinement. 



In the spring of 1909 the caterpillars from a few nests which had 

 been collected the winter before in the vicinity of this first satisfactory 

 field colony were fed in the laboratory, and from them a few cocoons 

 of Meteorus were secured. It was certain that the species had com- 

 pleted the cycle of the seasons in the open, but it was also rather 

 evident that it was not very common. If this were due to widespread 

 dispersion, as might easily be the case, it might possibly result in the 

 species spreading out so thin as to be lost, and it was resolved to place 

 the Meteorus reared in 1909 in the same general vicinity, on the theory 

 that by spreading over the same territory the colony might be mate- 

 rially strengthened throughout. This was done, and about 2,000 

 individuals were liberated during that spring and summer, the most 



