244 



PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 



enough, yellow in the case of the Japanese, and black in that of the 

 European species. Between three and four weeks of ordinary 

 summer weather are necessary for the complete life cycle. 



The adults are very long lived, and a few of both species were kept 

 in confinement from early in August, 1910, until December of the 

 same year. During this time they were offered numerous sorts of 

 pupa3, but after it was no longer possible to secure those of the gipsy 

 moth there was no further reproduction. It has always been supposed 

 that it was the adults which hibernated, and the longevity of the 

 individuals mentioned above lends strength to this supposition. If 



Fig. 51.— Monodontomer us xreus: Adult female. Greatly enlarged. (Original.) 



correct, there need be only a single generation annually, and the 

 species would therefore be independent of any other host. Neither 

 is known to attack the brown-tail moth, but both have been reared 

 through their transformations upon pupae of the white-marked 

 tussock moth. 



Both of the species of Chalcis are of considerable importance as 

 parasites of the gipsy-moth pupae in their respective habits, and so 

 far there has nothing occurred to destroy confidence in their ability to 

 become of importance here provided a sufficiently large number may 

 be secured to enable them to become established. It is confidently 

 expected that they will disperse at a very rapid rate, and on this 

 account it will be necessary that the colonies be large and strong, so 

 that extinction through too great scarcity during the first or second 

 season following colonization will not result. Renewed efforts to 

 make this possible will be made this coming season, and at the same 



