52 Trans. Acad. Sci. of St. Louis. 



in the first lot. Then again we find that the duration of 

 copulation does not influence the fertility of the eggs, 

 whether they be few or many. (See Table 29.) 



We shall not go into the analysis of these data of the 

 South St. Louis Cecropias, since the per cents correspond 

 so closely to those already discussed. (See Table 30.) 



The New York Cecropias furnish very interesting 

 comparative data. The per cents of fertility and via- 

 bility are practically identical with those from a distant 

 locality of different climate. (See Table 30.) 



This lot is rich in 2-hour matings, which give the same 

 good results of high fertility — much higher in fact than 

 some of the normal matings. This again conclusively 

 demonstrates that 2 hours of copulation is quite suffi- 

 cient for the propagation of the race. 



PHILOSAMIA CYNTHIA. 



Our observations on the fertility in P. cynthia are 

 based upon two lots of material, one from New York 

 City and one from Philadelphia, Pa. 



This species seems not to be monogamous, like our 

 Cecropias, but some of the New York insects mated 

 twice, and some members of the Philadelphia lot mated 

 two and three times. Normal mating in .this species is 

 the same as in the Cecropias, i. e., continuous mating 

 from early morning until about dark, or sometimes a 

 little later. It will be noted that in both tables a few in- 

 dividuals have no record of length of time in mating. In 

 these cases they were found already in copulo when the 

 examination was made in the morning, and they had al- 

 ready separated before the usual time of inspection in 

 the afternoon, so we do not know with certainty the exact 

 duration of the mating. In the cases where they were 

 artificially separated, the duration is indicated by the 

 number placed after the date of mating. 



The counting of the empty egg-shells and the dead 

 larvae in each vial was a comparatively easy task, but 



