( xcvii ) 



Copulation, lasting 55 minutes, occurred on Aug. 30, 1910, 

 between a female astyanax, bred from a Brooklyn larva, and 

 a male arthemis captured at Alstead Center. The female in 

 nine days from Sept. 5 deposited 82 eggs on the leaves of 

 wild cherry. From these eggs 8 imagos were reared — " five 

 males and three females, all rather dark examples of proser- 

 pina." Attempts to breed these butterflies together and with 

 other Basilarchias were unsuccessful. A male and female of 

 these proserpina were figured on the accompanying Plate VII. 

 As a result of the breeding experiments the author justly 

 claimed that " the hybrid character of arthechippus and 

 proserpina is now established," while the facts recorded in 

 the second paper " make it clear that proserpina will at least 

 breed with one of the parent species." 



The author was much to be congratulated on the successful 

 results of his carefully conducted and important researches. It 

 was now reasonable to conclude that arthemis and astyanax were 

 subspecies or geographical races of a single species,interbreeding, 

 not indeed commonly, but quite normally with the production 

 of fertile offspring, in their zone of overlap. Furthermore, the 

 rarity of proserpina as compared with both the parent forms 

 pointed strongly to the reality of sexual preference as a factor 

 in evolution. From the observed facts it could hardly be 

 doubted that arthemis as a rule preferred to mate with arthemis 

 and astyanax with astyanax. The male genitalia of arthemis 

 and astyanax were closely similar, as shown by the figures 

 of Scudder (" Butterflies of the Eastern United States and 

 Canada," Cambridge, Mass., 1889, Plate 33, figs. 9 and 15) 

 and Eltringham (" Mimicry in North American Butterflies : A 

 Keply " ; Poulton, Proc. Acad. Sci. Phila., 1914, p. 161, Plate V, 

 figs. 5 and 4), whereas those of archippus (Scudder, figs. 11,12; 

 Eltringham, fig. 6) were distinctly different from either. Fur- 

 thermore, the extreme rarity of arthechippus pointed to a 

 strong disinclination to pair — all the more evident inasmuch as 

 the common range of archippus and arthemis was much wider 

 than that of astyanax and arthemis. In fact, according to 

 Scudder, the area of arthemis- — Canada east of the Rockies, 

 and the north-eastern States — was wholly included within 

 that of archippus. A further indication that the pairings of 



PROC. ENT. SOC. LOND., V. 1916 G 



