THE CALOSOMA BEETLE IN NEW ENGLAND. 



15 



that no wholesale injury to the species is caused by their feeding on 

 poisoned caterpillars. 



STARVATION EXPERIMENTS. 



In 1910 experiments were conducted to determine the length of 

 time that these beetles could survive without food. For this purpose 

 two pairs of young beetles and two pairs of old beetles were placed 

 in jars of earth in one of the cages in the laboratory yard. The 

 results of the experiment are shown in Table II : 



Table II. — Starvation experiment to determine the length of time adult 

 Calosoma sycophanta can live without food. 



Calosoma sycophanta. 



Date 

 emerged 



from 

 hiberna- 

 tion. 



Date 

 male 

 died. 



Length of time 

 male lived with- 

 out food. 



Date 

 female 

 died. 



Length of time 

 female lived 

 without food. 





1910. 

 Mav 26 

 ...do...„. 



1910. 

 June 26 

 June 29 

 July 17 

 June 30 



1 month 



1910. 



July 9 



July 5 



June 26 



C 1 ) 



1 month 13 days. 

 1 month 9 days. 



Do 



1 month 3 days 



1 month 21 days... 

 1 month 4 days 





...do 



1 month. 



Do 



...do 



1 month 21 days. 1 







1 This female, after living without food for 1 month and 21 days, was offered several full-grown gipsy-moth 

 caterpillars July 17 and ate two in 10 minutes. The next day a male was added and copulation was 

 attempted several times, but without satisfactory results. The female died July 30 without depositing 

 eggs. During the 12 days the pair were in the jar 33 sixth-stage gipsy-moth caterpillars were eaten. 



This experiment shows that beetles of this species can live during 

 the summer for a month or more without food. Old beetles appear 

 to withstand starvation better than young beetles, and males die 

 sooner than females. In 1907 a field colony of beetles was liberated 

 in order to test their ability to survive where the food supply was 

 very limited. Fifty specimens, 25 of each sex, were liberated in 

 woodland at Peabody, Mass., August 28. The beetles were received 

 from Europe early in the month and had been supplied with very 

 little food after their arrival. At the time they were liberated there 

 were no gipsy-moth caterpillars in the field and very few pupse. An 

 occasional native caterpillar could be found, but they were rare in 

 the vicinity of the colony. Several examinations were made the fol- 

 lowing spring and summer. On July 8 Calosoma larvae were found, 

 showing that the species had survived and that reproduction had 

 taken place. This indicates that the beetles are able to survive under 

 very unfavorable conditions. 



In order to determine how far male beetles might be attracted by 

 females, several experiments were conducted, but negative results 

 were secured. 



REPRODUCTION. 



After emerging from hibernation and feeding for a few days, cop- 

 ulation takes place and eggs are deposited by the females. It is neces- 



