46 BULLETIN 417, U. S. DEPARTMENT OF AGRICULTURE. 



Table 9. — Feeding records of four -pairs of Calosoma frigidum, 1909 and 1910. 



Pair No. and 

 year. 



Feeding 

 r3cord 

 started. 



Ceased 

 feeding. 



Sixth-stage caterpillars. 



Malaco- 

 soma 



ameri- 

 cana. 



Porthe- 



tria 

 dispar. 



Total. 



2731 (1909) 



4832 (1910) 



4837 (1910) 



4838 (1910) 

 Average, 



June 20 

 2 



4 

 4 

 L46. 



Aug. 20 



July 12 



13 



27 



77 

 92 

 35 

 51 



153 

 100 



20 



57 



230 

 192 

 55 

 108 



Some of these beetles died and others entered hibernation at the 

 end of the season. 



Pair No. 2731 were collected in eastern Massachusetts during June, 

 1909, and reproduced in the jar that year. Thirty-seven fertile eggs 

 were deposited by the female — a reason for the large amount of food 

 eaten. None of the other females, all of which were pupse of the 

 fall of 1909, reproduced, consequently less food was required. 



The records in no case were started as soon as the beetles emerged 

 from hibernation, as some were collected in the field and the young 

 stock that emerged in cages were retained until mates could be 

 secured from the field. Unfortunately, record No. 4832, which 

 promised to reach as high a limit as No. 2731, was discontinued a short 

 time before the beetles ceased feeding normally. The beetles con- 

 sumed from 55 to 230 full-grown caterpillars of M. americana and P. 

 dispar, or an average of 146 to each pair. This average, without 

 doubt, would have reached approximately 200 caterpillars had all 

 the records been continued through the whole season, and if a larger 

 percentage of the females had been more than one year old. 



The beetles referred to in Table 9 emerged from hibernation between 

 May 20 and June 9 and fed as late as August 20, but most of them 

 ceased activity during the latter part of July. The active feeding 

 period, therefore, extends over two to three months. 



REPRODUCTION. 



Two pairs of beetles confined in jars in 1909 were kept under obser- 

 vation for reproduction. One pair produced 37 eggs between June 

 21 and June 30. They were seen in copulation on June 24, 27, and 

 29, and died August 30 and 31 of that year, after having consumed 

 230 full-grown caterpillars of Malacosoma americana and Porthetria 

 dispar. 



In 1910 six pairs were confined in jars but only one pair repro- 

 duced. The female deposited eggs June 28 and 29, but only two 

 hatched. In these experiments were one male and four females that 

 were reared at the laboratory in 1909, and one of the females, which 

 was paired with a male collected during the spring, deposited eggs. 



One pair of the beetles (pupa3 of the summer of 1909) lived until 

 July 6, 1911, but did not reproduce in 1910 or 1911, nor were they 

 seen in copulation either year. 



During the year 1911 five pairs of beetles were under observation 

 for reproduction. None of these were seen in copulation and only 



