THE GENUS CALOSOMA. 



73 



at various times, but did not climb more than 4 or 5 inches. These 

 larvae were then removed and others substituted. June 24 two first 

 and two second stage larvse were tested, and one climbed 2 feet before 

 falling. June 25 at 8 a. m. one of the second-stage larvse was found 

 on the bark of the tree 18 inches from the ground, but there were no 

 signs that it or the others had entered the food cage at the top during 

 the night. 



June 26 a sixth-stage caterpillar of Porthetria dispar was found 

 devoured in the food cage at the top, evidently by a third-stage larva, 

 as there was a large hole in one side of the caterpillar where it had 

 entered. A second-stage larva when placed upon the tree crawled 

 up 18 inches before falling. 



June 27, in the forenoon, a third-stage larva was found on the bark 

 15 inches from the ground, but it had not entered the food cage during 

 the night. 



June 28, in the forenoon, the same larva was again found on the bark 

 of the tree 6 inches from the ground. 



June 29, in the forenoon, a third-stage larva was found in the food 

 cage at the top of the tree, and had devoured a sixth-stage caterpillar. 



July 3 a second-stage larva was found in the earth at the base of 

 the tree, but had entered the food cage at the top during the night 

 and devoured two sixth-stage caterpillars of Porthetria dispar. 



July 4 it was again noted that the larva had entered the food cage 

 and devoured another large caterpillar. 



July 5 the same operation was again noted except that this time a 

 part of two caterpillars had been consumed. July 11 the larva died 

 after growing weaker for two or three days. It had probably been 

 injured in falling. 



These experiments reveal the fact that larvae of this species can and 

 do climb in all stages. The first-stage larvae did not quite reach the 

 food cage at the top while the second and third stage larvae seemed to 

 have easy ingress and egress. These results compare quite favorably 

 with the climbing habits of larvae of Calosoma sycophanta. 



CANNIBALISM AMONG LARVAE. 



An experiment was conducted in the summer of 1909 to find out 

 how many days after hatching these larvae could be fed together in 

 jars before planting them in colonies in the field. They were con- 

 fined in large battery jars about 8 inches deep and 6 inches in diameter 

 with about 2 inches of earth in the bottom. Caterpillars of Porthetria 

 dispar were supplied daily with fresh leaves so as to keep them feeding 

 on the earth and to enable the larvae of Calosoma reticulation to reach 

 them easily. The larvae hatched between June 21 and June 29, 1909, 

 and were all removed from the jars, Julv 1. The results are given in 

 Table 19. 



Table 19. — Extent to which larvse of Calosoma reticulatum prey on one another. 



Number 



Per cent 



Number 



Per cent 



of days 



alive 



of days 



alive 



after 



when re- 



after 



when re- 



hatching. 



moved. 



hatching. 



moved. 



Days. 





Days. 





11 



21 



6 



43 



10 



25 



5 



40 



8 



7 



n 



3 



94 



