40 BULLETIN 251, U. S. DEPARTMENT OF AGRICULTURE. 



points which increase the usefulness of this insect. The life history 

 of the beetles and the larvae corresponds very closely to that of the 

 larval and pupal stages of the gipsy moth, so that they are especially 

 adapted to attack this pest. The climbing habits of the Calosoma 

 larvae enable these creatures to obtain food upon the trees and in this 

 way an opportunity is furnished for the species to increase in large 

 numbers. The fact that the adults commonly live 2 or 3 years, and 

 sometimes 4 years or more, makes it possible for the species to survive 

 under unfavorable conditions. The chances for the species to exist 

 are further increased by the fact that reproduction by the same indi- 

 viduals may occur on alternate years. The species is capable of exist- 

 ing for long periods without food, and passes through hibernation 

 very successfully under New England climatic conditions. All these 

 factors make it an excellent addition to our fauna, and from the 

 results which have been secured from experimental records and in 

 the field it appears that the species at present ranks first among the 

 introduced natural enemies of the gipsy moth. During the summer 

 of 1914 a large amount of field data was secured to determine the 

 relative importance of the different natural enemies of this insect. 

 The results of 1914 indicate that the Calosoma beetle was the most 

 important single factor. The insect continues to spread each year, 

 and in all probability will soon be present throughout the entire 

 territory where the gipsy moth is known to exist. There is no good 

 reason to suppose that it may not spread in small numbers to places 

 outside this territory if sufficient and proper food can be found. 



Beetles sent to New Brunswick, Canada, survived the winter satis- 

 factorily, and the same is true of specimens forwarded to New Mexico, 

 which indicates that the insect is able to survive under quite different 

 climatic conditions. 



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