44 CALOSOMA SYCOPHAXTA. 



The following year (1910) 1,224 larvae were placed in similar cages 

 or cylinders between July 26 and August 16, and only 5 per cent 

 were killed by their comrades. Some cold storage gipsy moth 

 pupae were supplied, but they were in very good condition for feeding 

 to the Calosoma larvae. 



The Distance Calosoma Larvje Penetrate the Ground to Pupate. 



The distance which the larvae of this species penetrate the ground 

 for the purpose of forming their pupal chambers varies greatly, and 

 seems to be governed largely by the character of the soil, and the 

 amount of moisture which it contains. 



Few observations have been made on Calosoma larvae that feed 

 under natural conditions, as it is a difficult matter to find hibernating 

 beetles in the ground, even in our most prosperous colonies. 



It is probable that if the ground is hard and dry — as is usually the 

 case in midsummer— the larvae are not able to descend for more than 

 a few inches below the surface. In one of our cages during the 

 summer of 1909 a larva burrowed under a board and formed a pupal 

 chamber beneath it, so that a living pupa was readily exposed by 

 lifting the board. The cage experiments at the laboratory do not 

 offer typical data on this point, for the reason that it is necessary to 

 fill the cages with fresh earth when they are set in the ground early 

 in the summer, so that the soil is not as compact as it would be under 

 natural conditions. In 1908, several larvae pupated in jars partly 

 filled with earth. As a rule the pupal cavities were made at or near 

 the bottom of the jar, and these were from one-half an inch to 3 

 inches below the surface. 



A record of 20 Calosoma pupae — 12 males and 8 females — which 

 made cavities, during the fall of 1908 and 1909, shows that they 

 penetrated from 4 to 8 inches below the surface in outdoor cages. 

 The average distance for males was 6§ inches and for females 1\ 

 inches. Seven males and 5 females went to the bottom of a cage 

 which contained 8 inches of soil. Under natural conditions the 

 Calosoma larvae probably will not burrow more than from 4 to 5 

 inches into the ground before making the pupal chamber. Thus the 

 insect must remain considerably above the frost line during the 

 winter. In some rare cases Calosoma larvae have successfully pupated 

 on the surface of the ground, and in nature they may sometimes 

 pupate under the leaves or vegetable mold in forest areas. 



The distance that the Calosoma larvae go into the ground to form 

 their pupal chamber corresponds very well with the distance which 

 the Calosoma beetles will burrow for the purpose of going into hiber- 

 nation, and several records bearing on this point mil be given later 

 under the head of hibernation of the beetles. 



