THE GENUS CALOSOMA. 35 



EXPERIMENT TO DETERMINE THE RELATIVE AMOUNT OF FOOD DEVOURED BY ADULTS 

 DURING DAY AND NIGHT. 



In connection with the idea of colonizing this species in a green- 

 house where cutworms (Noctua clandestina Harr.) are abundant sev- 

 eral times in the year, it was thought advisable to secure some infor- 

 mation on the feeding of this species upon cutworms. Two large 

 battery jars two-thirds full of earth, each containing one male and 

 two females, were used for the experiment. In one jar cutworms 

 were buried in the earth at 5 p. m. and the jar immediately set in a 

 dark closet until 8 a. m. the following morning when the count of 

 devoured and unharmed cutworms was made. All living cutworms 

 were removed until 5 p. m. on this day when they were returned to 

 the jar with others. In the other jar cutworms were buried at 8 

 a. m. and the count of devoured and living was taken at 5 p. m. 

 They were then removed from this jar until 8 a. m. the following 

 morning. Green grass was placed on the surface of the earth in the 

 jars each time to furnish food for the cutworms and the latter were 

 buried about one and one-half inches below the surface. 



The experiment was started June 19 and concluded June 28 because 

 the supply of food was no longer available. After June 24 the cut- 

 worms were left in the jars all the time, but records of feeding were 

 made at 5 p. m. and 8 a. m. Fifty-seven full-grown cutworms were 

 devoured by the beetles during the night and four during the day, 

 or 14 times as many were eaten at night as during the daytime. It 

 is evident from these experiments and other jar records that the 

 adults of this species burrow into the ground very little in search of 

 food but take the opportunity to seize their prey whenever it is met 

 (day or night) on or above the surface of the ground. This species 

 destroys large numbers of cutworms as well as arboreal caterpillars. 



THE PUPA. 



One male pupa of this species measured 20 mm. long and 8 mm. 

 wide. No female pupa? were secured for observation. 



Some observations were made upon the change and development 

 of pupae during the fall of 1909. Some of the larvae constructed their 

 cavities at the bottom of the jars and next to the sides, which made 

 it comparatively easy to observe their daily changes in appearance. 

 The following notes were secured from a pupa observed at that time: 



No. 2884-A. September 23, larva hatched and placed in small jar. 



October 3, larva cast first exuvium. 



October 16, larva cast second exuvium. 



October 23, larva ceased feeding and shortly after that date probably began mak- 

 ing cavity. It had made tunnels all through the earth at that time. 



October 30, larva pupated in cavity at bottom of jar. 



Pupa creamy white and lay on dorsal side. It was observed daily for changes of 

 color, but such changes were very gradual. 



November 9, elytra changing to slightly violet color. Eyes could not be plainly 

 seen from the outside. Abdomen still creamy white. 



November 12', beetle issued and remained in cavity. Jar filled with earth and 

 transferred to cellar of laboratory where it was allowed to pass the winter. The 

 pupal stage required 13 days in a temperature of from 68° to 75° F. 



It is not expected that pupae mature during the summer in much 

 shorter time than was required in the foregoing experiment, namely, 

 13 days. In the Southern States, where this species is commonly 

 found, the pupal stage may possibly be two or three days shorter. 



