INVESTIGATION OF LIFE HISTORY. 41 



was burlapped and examined the same as was the one at Waltham, 

 Mass., but no traces of Calosoma beetles have since been found. 



The results in these field colonies show that the beetle larvae are 

 sometimes able to develop even when the food supply is very scanty. 



Experiment to Determine Whether Calosoma Larvae Will Hibernate During 



the Winter. 



A Calosoma larva winch hatched August 7, 1907, and became 

 nearly full grown September 7, was placed in a cavity 6 inches below 

 the surface of the earth in a galvanized-iron cage out of doors. 



May 19, 1908, the cage was taken up and a dead Calosoma beetle 

 was found in the cavity where the larva had been placed. The 

 death of the insect was caused by the pressure of the earth upon it. 

 The weather was cool from the time the larva was buried until the 

 date of removal, hence this experiment shows that the insect does 

 not normally, and probably can not, hibernate in this stage. 



Placing Calosoma Larvae in Cold Storage to Determine Ability to With- 

 stand cold. 



The following experiment was tried to test the ability of larva? of 

 this species to withstand cold. 



August 8, 1907, two lots, each containing 4 Calosoma larvae (2 

 newly hatched larvae, 1 larva 6 days old, and 1 full-grown larva), 

 were sent to cold storage, where a temperature of 28° F. was main- 

 tained. The smaller larvae were placed in separate vials which con- 

 tained about 3 inches of earth, and plugged with cotton, while the 

 full-grown larvae were placed in jelly glasses containing about 2 inches 

 of earth. 



August 22, 1907, one lot was removed from storage. The 2 newly 

 hatched larvae were dead on top of the earth. The other 2 larvae 

 were in the ground and were apparently dead. 



August 27, 1907, another examination was made. All larvae failed 

 to revive, and the experiment was closed. 



June 4, 1908, the second lot was removed from storage. The 

 earth was very dry in both vials and jelly glasses. All larvae were 

 dead. 



These results indicate that the larvae will not survive cold storage, 

 but if they are full grown and are subjected to a gradual reduction of 

 temperature they will pupate and transform to beetles before becom- 

 ing dormant. 



Methods Used in Rearing Calosoma Larvae. 



During the progress of the work many experiments have been tried 

 in order to ascertain the best methods of rearing the Calosoma larvae. 

 If only a few specimens are desired for study the use of a small jar 



