278 'Journal of Cotnparative Neurology and Psychology. 



was evidenced by the gray appearance assumed a few days after 

 ovipositing — a color characteristic of the monovoltin egg, or egg 

 destined to he over the winter before issuing. An occasional non- 

 fertile egg occurs. This frequently occurs also in masses of eggs 

 oviposited under normal conditions. 



That the full quota of eggs were not procured in every case, as 

 the tables show, was due merely to the fact that the moth was not 

 submitted to a sufficient number of stimulations. In each case 

 where stimulations were continuous, an unexpectedly large number 

 of eggs were placed, for example Table IV, Nos. i and 3. In the 

 former (No. i) frequent stimulations occurred throughout Sept- 

 ember 6, two days after the moth had issued and twelve days 

 before death ensued. In the latter (No. 2) frequent stimulations 

 occurred throughout September 9, five days after the moth had 

 issued, then two stimulations twenty-four hours apart, and not 

 again for ninety-six hours, twenty-four hours before death ensued, 

 like results following in each case. 



These tables, therefore, with the supplementary data, show 

 again that the reproductive mechanism is perfect even for eight 

 or ten days ^fter decapitation, or as long as the moth lives. The 

 sperm also retains vitality for that length of time within the body 

 of the female. 



In Series 12, as in Series g, the moth was first decapitated and 

 either immediately afterward or from one to three days afterward, 

 mated. Mating takes place several days after decapitation with 

 the same ease as before decapitation. In every case, eggs followed 

 a few seconds after stimulation. Table V shows a series of indi- 

 viduals that were protected from external stimulus for several 

 days after decapitation (from one to fourteen) and subsequently 

 mated. 



Inspection of the table shows that while eggs are produced as 

 successfully upon the fifteenth day after issuing as upon the first, 

 those produced after the thirteenth day are apt to be unfertilized. 

 Either the vitality of the sperm has ceased, the mechanism for 

 the passage of sperm into vagina has ceased working, or there may 

 be an imperfect action on the part of the micropyle in the fifteen 

 day old eggs. As to whether this was true exclusively in moths 

 mated after decapitation was not sufficiently tested. The cement 

 gland secretion also gives out about this time and eggs are there- 

 after apt to be non-adhesive. 



