54 CALOSOMA SYCOPHANTA. 



"r.vuLK XI. — Fci'diruj records of 4 pairs of old Calosoma beetles, 1910. 



' Added male No. 4811. 2 Record discontinued. 3 Females laid eggs. 



Table XII. — Feeding records of Calosoma beetles, 1910. 



1 Female laid eggs. 



2 Female laid eggs; did not hatch. 



These tables show, on tlie average, that the okl Calosoma beetles 

 consume more food than young ones. This is undoubtedly due to 

 the greater reproduction which is common with the former. 



The average for the old beetles was 328 caterpillars and for the 

 young beetles 239, while the average for all the ])airs given in Tables 

 X, XI, and XII is 272 caterpillars. This is a fair average, as nearly 

 as can be determined, of the number of caterpillars that tlie Calosoma 

 beetles will actually destroy. In the field probably the number would 

 be increased, as feeding under natural conditions would undoubtedly 

 stimulate activity and appetite. 



In addition to the large number of experiments that has been 

 carried on to determine the amount of food that will be eaten by 

 Calosoma beetles that emerge from lubernation at the normal time, 

 several series were conducted with beetles that were taken from 

 hibernation in March, April, and May. Tliese beetles did not become 

 active and begin feeding for a considerable time after the cages were 

 removed to a warm room in the laboratory, but as small caterpillars 

 of various species, particularly brown-tail moth larvae that were 

 being fed in the laboratory, were used for food, large numbers were 

 destroyed before midsummer. Most of these caterpillars were small 

 and as soon as the Calosoma beetles became active large numbers 

 were required to satisfy their Iiunger. 



The average number of small brown-tail motli caterpillars eaten 

 by 3 pairs of Calosoma beetles removed April 9, 1908, was about 



