METHODS OF SECURING DATA FEOM COLONIES. 75 



were liberated during the summer of 1910 as had been released in all 

 the previous years. This does not 'hold true in regard to the number 

 of larvae liberated. 



Two years or more will be required before any accurate figures on 

 increase in the colonies planted in 1910, or spread from them, can 

 reasonably be expected. The information already given concerning 

 the reproduction of new and old beetles bears directly on the condi- 

 tions which exist in field colonies. If the beetles liberated in 1906 

 and 1907 reproduced at the normal rate, the progeny from these col- 

 onies should show far greater increase and dispersion than the beetles 

 more recently liberated, and that this is the case will be brought out 

 in the following pages. On the other hand, colonies consisting of 

 larvae, or beetles reared from larvae, can not be expected to show any 

 great increase for the first year or so, because young beetles ordinarily 

 oviposit sparingly. 



Owing to the fact that Calosoma sycophanta has been able to sur- 

 vive for a number of years under field conditions and that reproduc- 

 tion and dispersion have been going on at a satisfactory rate, as deter- 

 mined by observations made during the past four summers, it has been 

 considered inadvisable to make further importations of this species, 

 for the reason that if it is necessary to liberate more colonies aside 

 from those that can be supplied from the material now being held at 

 the laboratory, it should be possible to collect sufficient quantities 

 in the field for the purpose. 



METHODS OF SECURING DATA FROM FIELD COLONIES. 



Since the work began it has been of the utmost importance to 

 determine actual conditions in the field and to find out whether each 

 introduced species was surviving and reproducing. During 1907 

 numerous visits were made to the colonies which had been liberated, 

 but little of importance was found until about the middle of July, 

 when Mr. L. S. Winchester, who had been employed for a few weeks to 

 take up this particular work, found Calosoma beetle larvae under the 

 burlaps on trees where a colony had been planted in Burlington, Mass. 

 This, of course, showed that the beetles had successfully hibernated 

 during the winter and reproduced, and was a very encouraging sign. 

 Later in the month several larvae were found in the Saugus (Mass.) 

 colony and a single larva was found in one of the colonies at Lynnfield, 

 Mass., so that at the end of the season it was known definitely that 

 three of the six colonies liberated in 1906 were well established in the 

 field. 



During the examination of the colony liberated by Mr. Mosher at 

 North Saugus, Mass., in July, 1907, it was discovered, contrary to 

 expectations, that the larvae of this species climb the trees and feed 

 upon the caterpillars and pupae of the gipsy moth found on the trunks. 



