TNVESTlCATHi.X dl' l.ll'K lllSTOIiV. 57 



The IxM'tlos ill the ;tl)()Vt5 cxpcriiiKMils leinaiiiod a portion of tlic 

 time under the earth (hning the first two weeks, but from that time 

 until they died were always to bo seen on the surface at any hour 

 during the (hiy. 



Table XIII shows that the Calosoma beetles can survive for a 

 month witlKHit food, and under natural conditions in the field, w^lierc 

 more or less moisture is present, the lengtli of time would no doubt 

 be increased. Apparently old beetles can withstand starvation better 

 than young beetles, and males ai)j)ear to die sooner than females, 

 under these conditions, but several exceptions are to be noted in the 

 table. The number of specimens under consideration is not large 

 enough to give more than a general idea of tlie hardy nature of this 

 species. 



A field colony of Calosoma beetles was liberated in 1907 with the 

 idea of testing their a})ility to survive on a very limited food supply. 

 On August 28, 50 specimens, 25 of each sex, were li})erated in wood- 

 land in Peabody, Mass. These beetles had been received from 

 Europe during the month and had been supplied with very little food 

 since they arrived. At the date of liberation there were no gipsy 

 moth caterpillars in the field and very few pupae. Occasionally a 

 native caterpillar would be seen, but they were rare in tlie vicinity of 

 the colony. Under these conditions it appeared possible to make a 

 thorough test. 



The colony was examined the next spring and summer. On July 

 8 a Calosoma larva was found, sho\nng that reproduction had taken 

 place. This would indicate that tlie species can survive undervery 

 unfavoi-able conditions. 



AsSEMBLTNf! EXPERIMENTS. 



In the summer of 1910 it seemed desirable to carry on a few experi- 

 ments to determine, if possible, the distance that the male Calosoma 

 beetles are attracted by the females, and for tliis purpose a cage w^as 

 set lip in the salt marshes between Lynn and Kevcre, Mass. This 

 cage (fig. 20) w^as about 10 inches square and 12 inches high. The 

 sides were covered with mosquito netting and underneath a narrow 

 boaid which extended around the cage, and wliich was beveled on tlie 

 underside, was stretched a tliin sheet of rubber, which was attached 

 in such a way that beetles from the outside could gain admission but 

 could not escape. Within this cage was ])laced a wire C3'linder con- 

 taining both old and young females wliich had just emerged from 

 liibernation. 



June 13, 1910, this cage trap was set up in the marsh at a point 

 one-half mile or more distant from any trees. It was attached to a 

 pole about 8 feet high, and in the inner cage were 2 young and 2 old 



