44 Trans. Acad. Sci. of St. Louis. 



stage. The female, having a large mass of ova to pro- 

 duce, has perhaps little time or room to lay up as large a 

 store of reserve nourishment, and in many cases it may 

 be possible that the supply is insufficient to completely 

 carry it through the reproductive period, while in the male 

 it may be so great as to carry it far beyond. Again, if the 

 reserve nutriment be equal in both sexes, the earlier 

 death of the female may be due to the expenditure of a 

 greater amount of vitality in the efforts of egg laying. 



We have seen that those females, which had a male 

 almost in waiting, so to speak, when they hatched, were 

 overtaken by death when all the eggs had been deposited ; 

 we also found that death, after a time, likewise 

 overtook those less fortunate females, who mated late in 

 life and were cut short in their ovipositing regardless of 

 whether the propagation of the species was assured to 

 the fullest extent. For just this reason one is apt to 

 think that out of 68 cocoons 43 were males so that they 

 might be on hand to properly fertilize the females early 

 in life and thus insure perfect oviposition. 



Thus we are led to suppose that the greater number of 

 males is an adaptation for the good of the species, and 

 that perhaps this came about through natural selection. 

 But if natural selection produced a greater number of 

 males it also endowed them with a longer duration of 

 life, which is as useless to the individual as to the species. 



If natural selection is so great a factor in economic- 

 ally producing adaptation, would it not have been easier, 

 and perhaps better, to prolong the life of the female just 

 a few days or perhaps a few hours to insure perfect 

 oviposition, than to produce a greater number of males 

 and uselessly prolong their lives to insure impregnating 

 the females at an early age? Coulcl it not be possible 

 that the phenomena here observed are the incipient 

 stages of higher adaptation, or that at this stage of the 

 Cecropia moth we have a phylogenetic vestige of the time 

 when the long life of the male was of advantage to the 

 species? Perhaps before the mouth parts degenerated, 



