10 BULLETIN 417, U. S. DEPARTMENT OF AGRICULTURE. 



3 1 feet in diameter, prevented the larvae from making their escape. 

 A small amount of earth was placed in the circle. Later the size 

 of the circle was reduced to 21 inches in diameter and it was found 

 necessary to attach several partitions to the strip of tin, which 

 extended nearly to the tree, in order to prevent the larvae from 

 traveling around the outer part of the inclosure (PI. III). 



A food cage, the bottom of which was made of J-inch mesh cellar- 

 window screen and the sides and top of fly screen, was perched on 

 the flat top of each section of the tree. The cage was made just 

 large enough so that the bottom projected about one-half inch be- 

 yond the bark of the tree on all sides and the Calosoma larvae had 

 no difficulty in entering it if they were good climbers. P. dispar 

 caterpillars or pupae or both were placed in these cages, and the 

 presence of the beetle larvae could be easily determined by the in- 

 jured specimens in the cages. 



Tests were made with the larvae of 1 1 species of Calosoma, namely : 

 Sycophanta L., scrutator Fab., calidum Fab., frigidum Kirby, lugubre 

 Lee, externum Say, inquisitor L., reticulatum Fab., chinense Kirby, 

 semilaeve Lee, and cancellatum Esch. When possible the larvae in 

 each stage were used. 



The results secured demonstrate that sycophanta is a natural climber 

 in all larval stages; reticulatum larvae climb considerably and with 

 apparent ease; chinense climbs to some extent, but not so much as 

 the preceding species. Larvae of scrutator and lugubre are in about 

 the same class, and seem able to climb to a small extent, but are 

 very rarely inclined to do so. The larvae of the remaining 6 species, 

 calidum, frigidum, externum, inquisitor, semilaeve, and cancellatum show 

 very little ability and no inclination to ascend trees. 



Considerable information has been secured on the climbing habits 

 of several species of adults and this is given under the species con- 

 cerned. 



NATURAL ENEMIES OF CALOSOMA. 



It is undoubtedly true that beetles of this genus are destroyed in 

 more or less numbers each year by natural enemies. The principal 

 vertebrate enemies concerned are the toad, skunk, and various 

 species of insectivorous birds. A considerable number become the 

 prey of parasitic and predacious insects, although only a small amount 

 of data is at hand to prove this assertion. Several cases are on 

 record where adults of C. calidum have been found among the remains 

 taken from the stomachs of toads, and Mr. F. H. Mosher, of the 

 Bureau of Entomology, has observed these animals feeding on the 

 species in the field. This observation was confirmed by an exam- 

 ination of the excrement, which contained small particles of the 

 chitinous remains of this species. 



On July 9, 1912, Mr. J. E. Dudley, jr., of the Bureau of Entomology, 

 collected in Stoneham, Mass., a considerable amount of toad excre- 

 ment in which parts of C. calidum could readily be determined. 



During the summer of 1912 numerous observers reported that 

 skunks were undoubtedly feeding upon specimens of Calosoma syco- 

 phanta. Most of these reports came from sections where this beetle 

 was abundant and there seemed but little doubt as to the accuracy 

 of the reports, although definite data were lacking. In order to secure 



