INVESTIGATION OF LIFE HISTORY. 51 



careful experiments in order to determine the best cages to use for 

 the hibernation of these insects, and the results of these various tests 

 are given in order that others who may desire to carry on similar 

 work may profit by this experience. 



Experiments in Wintering Calosoma Beetles in Galvanized-Iron Cages. 



In the fall of 1907 it became necessary to place as many beetles 

 as possible in hibernation cages so that a supply would be available 

 for the rearing work of the following spring, as well as to make a 

 thorough test of the ability of this species to withstand a New England 

 winter. Several styles of cages were used for the purpose, and as it 

 was desired to place them out of doors a number of cages was con- 

 structed of galvanized iron. They were made in the form of a 

 cylinder, 20 inches long and 4 inches in diameter. A flange was 

 turned on the upper and lower edges so that wire netting could be 

 attached by means of a wire which encircled the cylinder at the base 

 of each flange. They were set in the ground so that 2 or 3 inches 

 of the cage protruded. Beetles were placed in these cylinder cages 

 in September, 1907. The following spring it was found that these 

 cages were very unsatisfactory for the purpose, as two-thirds or more 

 of the insects placed in them had died during the winter. The chief 

 trouble appeared to be due to the freezing and thawing of the earth 

 in the cylinder, which rendered it very compact, and in many cases 

 the beetles were crushed in their hibernation cavities or were unable 

 to make their way through the wet soil early in the spring. For- 

 tunately, several other styles of cages were used and better results 

 with them were secured. 



Experiments in Wintering Calosoma Beetles in Wire-Screen Cages. 



Several hibernation cages were made of galvanized-wire screen 

 having a |-inch mesh. This material is commonly used for screen- 

 ing cellar windows, and it forms an excellent cage. (See fig. 9, 

 p. 18.) 



Several experiments were also tried in using cages made of mos- 

 quito netting sunk into the ground and attached on one side to the 

 trunks of trees. The results with these cages were satisfactory, but 

 as the wire rusted badly it is impossible to use them for more than 

 one season, so that the cage previously mentioned is more desirable. 



Experiments in Wintering Calosoma Beetles in Box Cages. 



For hibernating large numbers of beetles use has been made of 

 tight wooden boxes about 24 inches deep, provided with galvanized 

 iron wire bottoms and covers, and these have proved satisfactory. 

 (See fig. 8, p. 17.) 



