INVESTIGATION OF LIFE HISTORY. 



59 



Only negative results were secured from these experiments. It is 

 probable that the tests* should have been started earlier in June. 



Copulation. 



After emerging from hibernation and feeding for a few days the 

 beetles copulate, and egg laying is begun by the females. It is 

 necessary for them to be mated with the males several times during 

 the season, or a large percentage of infertile eggs will be laid. The 

 record of a pair of beetles which were kept in a jar for the third sum- 

 mer is interesting as it gives data on the frequency of copulation of 

 this species. The jar was examined once or twice a day when feeding 

 records or other notes were being made. The pair was found in coilu 

 June 27, 29, 30, July 8, 9, 10, 14, 15, 17, 18, 19, 20, and 26. They 

 must have copulated at other times, because fertile eggs were laid on 

 the date of the first copulation noted. The female deposited 274 

 fertile eggs during the summer. Old beetles show a greater desire 

 to reproduce than young specimens. 



In several cases females have been observed to copulate late in the 

 summer, and no eggs were deposited thereafter. In each of these 

 instances when the females were isolated in the spring without a male 

 no fertile eggs were deposited until after a male was added and copu- 

 lation took place. This indicates that the females can not be impreg- 

 nated in the fall and lay fertile eggs the following season without 

 further mating. 



Reproduction. 



The highest number of eggs laid in a single season by a female was 

 653. The next highest number recorded is 514. These records are 

 far above the average, as is shown in the following table: 



Table XIV. — Average number of eggs laid by females of Calosoma sycophanta during 



' 1908-1910. 



Year. 



Females 

 ovipos- 

 iting. 



Females 

 not ovi- 

 positing. 



Total 

 females. 



Number 

 of eggs. 



Average 



for 

 females 

 ovipos- 

 iting. 



Average 



for all 

 females. 



1908 



20 

 52 

 72 



4 

 23 

 26 



24 

 75 

 98 



1,662 

 8,115 

 8,720 



83 

 156 

 121 



69 



1909 



108 



1910 



89 



The data for 1909 and 1910 are probably the most valuable, as a 

 larger number of specimens was under observation and fewer experi- 

 ments had to be conducted with material taken direct from European 

 shipments. 



It will be noted that nearly one- third of the females did not deposit 

 eggs, and it should be stated that most of these were young beetles. 



