282 ERNEST WARREN. 



p. 276) is that no copulation occurred, but that the close 

 proximity of a male nevertheless influenced the female to lay 

 a good supply of eggs. These eggs simply exhibited the 

 normal amount of parthenogenesis inherent in the eggs of this 

 species. The parthenogenetic power, like any other character, 

 would be expected to vary to a certain extent from individual 

 to individual ; but the laws of probability are against the 

 supposition that the generally much increased parthenogenesis, 

 and the freedom of egg-laying observable in the paired moths 

 arose purely accidentally through the chance selection of such 

 individuals, while none of the unpaired individuals possessed 

 these characters in a high degree. It may be added that the 

 further evidence that will be adduced from some of the other 

 pairings is entirely against such an explanation. 



A few observations on the remaining pairings that were 

 eifected may be made here. 



Menippe ? x Menippe c?. — The moths (list, p. 273, b) 

 were paired on October 22nd, 1914, and 121 eggs were laid. 

 The majority of the eggs were hatched on the morning of 

 November 16th, the same day as that on which the partheno- 

 genetic individual emerged. It was a damp, warm morning. 

 The eggs of one of the batches laid by the female did not 

 duly hatch. In this batch there were forty-six eggs. These 

 were opened and examined, and only one showed any sign of 

 development. Of the remaining seventy-five eggs there were 

 twelve irregularly scattered through the different batches 

 which did not hatch. On opening them eight showed no 

 sign of development and four contained well-formed dead 

 embryos. 



The batch of forty-six eggs which did not hatch Avere pre- 

 sumably laid before copulation, and the partial development 

 which occurred in the case of one egg was due to the normal 

 parthenogenesis. 



Maia ? x Menippe S- — In the case of these seven pair- 

 ings (see list, p. 273, c) it is less clear that copulation occurred, 

 and, if it did, the resulting effect was much less marked than in 

 the reciprocal cross of menippe ? x maia c?. Whether 



