76 Trans. Acad. Sci. of St. Louis. 



may it be that this group is now changing from polygamy 

 to monogamy, and that some characteristics belonging to 

 the former habit have not yet been pruned away? 



When we go into the details of the longevity and ovi- 

 position of each individual we find many exceptions to 

 this hypothetical principle of longevity as an adaptation 

 for the benefit of the species; some are cut short in the 

 midst of reproduction, while others continue an ex- 

 tended, useless life. But how do we know that this fine 

 balance of longevity and oviposition is not interrupted 

 by some of the details of environment, such as climate, 

 moisture, etc.? May it be that these individuals which 

 do not conform to this principle of the factors of 

 longevity and oviposition are merely the ones which are 

 doomed to probable elimination? Natural selection may 

 now be at work building up these fine adjustments ; those 

 which conform to this principle are those which are sur- 

 viving by the cumulative effects of their complete and 

 abundant reproduction, while tjhose contrary individ- 

 uals may be the straggling element, always present in 

 any population, undergoing elimination by their own 

 failure to oviposit adequately. 



In regard to the portion of the lifetime spent in 

 copulo, it must be felt that here natural selection has not 

 done refined work in having not reduced, during the 

 phylogeny of the species, the time thus spent to a mini- 

 mum in order to waste none of the allotted precious 

 hours which the female has in which to oviposit. 



In most cases we find the mated females depositing 

 a greater per cent, of their eggs than the unmated indi- 

 viduals, while in every population they lived a shorter 

 time than their unmated sisters. This longer life of the 

 unmated female in every case might suggest that Nature 

 is indicating in this way that it is the species rather than 

 the individual that she cares for. Still their lease of 

 life was sufficient to attend to this duty in the propaga- 

 tion of the species. This evidence harmonizes to a de- 

 gree with Weissmann's theory of longevity being regu- 



