40 



BULLETIN 417, U. S. DEPARTMENT OF AGEICULTURE. 

 Table 6. — Feeding records of Calosoma wilcoxi — ^^Continued. 



THREE PAIRS, 1910. 



Pair 

 No. 



Emerged 

 from 

 hiber- 

 nation. 



Ceased 

 feeding. 



Fifth and sixth 

 stage caterpillars. 



Total. 



Mala- 

 cosoma 

 ameri- 

 cana. 



Porthe- 



tria 

 dispar. 



1791 



2 1792 

 1795 



1910. 

 1 May 26 

 2 23 

 26 



July 12 

 11 

 11 



47 

 114 

 60 



17 

 17 

 16 



G4 



131 



76 



1 c? Emerged June 4. 



2 June 13 and 22, 4 fertile eggs were deposited. 



The records in Table 6 are not normal, as the beetles were received 

 from the South that year. The beetles also ceased feeding early in 

 the season in 1909, as compared with that date for the same beetles 

 in 1910. June 23 was the average date in 1909 and July 11 in 1910. 

 The average number of fifth and sixth stage caterpillars eaten in 1909 

 was 66, while in 1910 it reached 90, and almost all that were fed in 

 the latter year were in the sixth sta^e. The average number of large 

 caterpillars consumed by one pair of beetles in two years was 75 each 

 year. There was very little reproduction of this species in confine- 

 ment, and it is reasonable to expect that they might consume even 

 more food under natural conditions. Ninety caterpillars, such as 

 were fed in Table 6, should equal approximately 250 caterpillars of 

 Paleacrita vernata Peck or Alsophila pometaria Harr., the latter of 

 which is supposed to form the principal diet of this species in the 

 field. In 1910 the active feeding period of the confined beetles 

 extended over 46 days. 



REPRODUCTION. 



Close observations were made upon five pairs of beetles received 

 May 18, 1909, through the remainder of the season, but none of this 

 series reproduced that year. Thirteen males and 25 females received 

 somewhat later were placed in a large Rdey cage with an ample supply 

 of caterpillars. June 6 one pair was seen in copulation and on June 

 19 both eggs and larvae were removed from the cage. Newly hatched 

 larvas were also found June 20 and 22. Seventeen fertile eggs or 

 larvae was the total output from the whole supply of beetles in 1909, 

 and these were probably the progeny of the female seen in copulation. 

 One hundred and sixty-four fertile eggs were deposited in 1910 by 

 one or some of the 17 females that emerged from hibernation. The 

 low rate of reproduction, in 1910 at least, was possibly due to the 

 scarcity of males, since only three males lived to emerge from hiber- 

 nation with the 17 females in the large cage. This does not entirely 

 explain the low egg record secured, as no infertile eggs were found. 

 Females of C. sycophanta commonly deposit large numbers of infertile 

 eggs when in confinement without a male, and sometimes do this 

 early in the spring, before their mates have emerged from hibernation. 



