TNVKSTICAl'ION OF LIKI'. IIISTOItV. 



58 



iiito liibernutidii, aiul, as a. rule, the hoctlos nvv. rather slii}j;^asJi in 

 movements. 



Many recortis haA'c been secm-ecl, but tlie most typical are })erJmp.s 

 the ones obtamed durmg the summer ol" 1910. Twelve ])airs of 

 Calosoma beetles were kept under observation, bchifjj led hi jars. 

 There were 4 pairs of old beetles, the same nunil)er ol" youn^; beetles, 

 old males and younjij females, and old females and youii^ males. 



Tlie earliest emergence was noted on May 25 and the latest on June 

 5. Feedmji; was coni])leted between July 5 and Au<2:ust 9. The sliort- 

 e?^t feedmg period was 32 (biys and the longest 66 days, with 50 days 

 as an average. 



The feeding period corresponds fairly well witli that of tlie cater- 

 pillars of the gipsy moth. The beetles do not emerge at c^uite as 

 earh' a chite m the spring as that upon wdiich the gipsy moth cater- 

 l)illars hatch, and in the fall the gipsy motJi has transformed and 

 deposited its eggs before the Calosoma beetles seek hibernation. 



Food of the Adults. 



The food of the adult beetles is similar to tluit of tlie larvae. Each 

 year some of the Calosoma beetles liave been fed on native lepidop- 

 terous larvae and none of the species offered was rejected by them. 



If tlie weather is cool in the early summer, the beetles remain on 

 the ground, usually under leaves or litter, and sally forth on the 

 first warm days in search of food. As soon as caterpillars become 

 scarce, late in July or early in August, the beetles feed less and 

 spend most of the time beneath the ground, soon burrowing down to 

 form the hibernating cell. 



Elaborate experiments liave been conducted each year since 1907 

 to determine the number of gips^^-moth caterpillars that are destroyed 

 by these predaceous beetles and a mass of data has accumulated 

 from which typical results have been selected. The most complete 

 series of experiments was conducted during tlie year 1910, and the 

 results are summarized in Tables X, XI, and XII. 



Sixth-stage tent caterpillars and gipsy-moth caterpillars were used, 

 as they were of about the same size and ofl'ered a fairly uniform 

 ration on which to base the average amount of food consumed. 

 Table X.. — Feeding records of 4 pairs of young Calosoma beetles, 1910. 



» Females laid eggs. 



