PARASITES OF GIPSY-MOTH PUP^. 255 



earth, and effectually demonstrated the superiority of this method 

 over that involving the use of the large out-of-door cages. The fol- 

 lowing spring the work was undertaken upon a considerably larger 

 scale, and along still more specially developed lines. From the 

 hibernated parent stock, and from newly imported beetles, he reared 

 large numbers of larvae, a part of which were allowed to complete 

 their transformations in confinement, while others were colonized 

 directly in the open when about half grown. These larval colonies 

 promised to be successful, and accordingly the work of rearing the 

 larvae and distributing them throughout the gipsy-moth-infested area 

 in eastern Massachusetts, with an occasional incursion into other 

 parts of the infested area, was continued throughout 1909 and 1910. 



Meanwhile, beginning in the late summer of 1907 and continuing 

 uninterruptedly until the close of the season of 1910, Calosoma has 

 been steadily gaining in the confidence of those who have watched 

 its progress. Its larvae were first recovered from the field at just 

 about the time when Mr. Burgess first took over the beetle work, and 

 its ability to complete its seasonal cycle in America unassisted was 

 thus indicated. The large colony was also proved to be unnecessary. 



Its progress in the field was slow at first, even in the instance of 

 the large adult colony founded in 1907 before it was known to have 

 become established. In 1908 its larvae were found in abundance in 

 the center of this colony, but not to any great distance away from 

 the point where the beetles had first been liberated. In 1909 the 

 spread was more rapid, but at the same time restricted in comparison 

 with that which became evident in 1910. As will be seen by reference 

 to the accompanying map (PL XXIV) which has been prepared by 

 Mr. Burgess from the results of the scouting work of three } x ears, its 

 apparent or discernible dispersion has been at a rapidly increasing 

 rate each year in the instance of colonies which, like these, chanced 

 to be so happily located as to allow for unrestricted and uninter- 

 rupted increase from the start. 



At the present time there is every prospect that a continued rapid 

 increase for a few years more will result in an abundance of the 

 beetles sufficient to render very efficient aid in the fight against the 

 moth. It is not expected that they will be of very much assistance 

 in localities in which the moth is reduced to such numbers as to make 

 control through parasites such as Compsilura and others of its char- 

 acter possible, but it is expected that whenever the moth breaks out 

 of bounds, and increases to such abundance as to afford the beetles 

 and their larvae an unlimited food supply, first migration and later 

 rapid multiplication of the beetle will result. In this respect the 

 role plaj^ed by Calosoma is similar to that which is rather confidently 

 expected of Blepharipa. 



