52 CALOSOMA SYCOPHANTA. 



Effect of Removing Calosoma Beetles from Hibernation Early in the 



Spring. 



In the spring of 1908 several series of experiments were conducted 

 in order to determine whether it is possible to remove Calosoma 

 beetles from hibernation before the normal time, feed them under 

 laboratory conditions, and be able to produce more than one genera- 

 tion of beetles a year. If tins work could be carried on it would be 

 of considerable biological interest and would increase the number of 

 specimens that could be liberated in field colonies. In order to make 

 these tests, several cages containing hibernating Calosoma beetles 

 were removed from the ground March 4, 1908. The weather was 

 very cold, and it was necessary to cut through from 7 to 14 inches of 

 frost before the cages could be taken out. They were brought to 

 the laboratory and allowed to warm up gradually with the expecta- 

 tion that the beetles would emerge from the earth in a short time, 

 begin feeding, and deposit eggs. As a matter of fact, they emerged 

 slowly, and after reaching the top of the earth in the cages they were 

 placed hi jars of earth and furnished with caterpillars which were 

 being reared in the laboratory. Similar lots of beetles were removed 

 from hibernation in April and May. The results of the experiments 

 indicate that it is possible to remove beetles in this way, but an extra 

 generation can not be developed during the summer. The larva? 

 did not become full grown much sooner than those that developed 

 from eggs laid at the normal time. 



Feeding Habits of the Adults. 



The adults climb trees, travel out on the branches and twigs, and 

 occasionally cling to the leaves while searching for caterpillars. If 

 disturbed, they fall to the ground and instantly seek shelter under 

 leaves or rubbish. Gipsy-moth and brown-tail moth caterpillars are 

 attacked while the Calosoma beetles are in the trees, the favorite 

 point of attack on the caterpillar being in the middle of the back. 

 They are firmly grasped by the sharp mandibles of the beetle, and 

 after many frantic efforts on the part of the victim to escape the 

 integument is ruptured and the beetle proceeds to feed on the con- 

 tents of the body. Very rarely does the gipsy-moth or the brown- 

 tail moth caterpillar escape without serious injury, and this never 

 occurs if a firm hold is once secured by the predatory Calosoma. 

 Occasionally beetles will be seen carrying the caterpillars in their 



jaws. 



Length of Feeding Period of the Adults. 



The active feeding period of Calosoma beetles extends from the 

 date the beetles emerge in the spring from hibernation until about 

 two weeks before they enter hibernation hi the fall. But little food 

 is consumed during the two weeks immediately preceding entrance 



