No. 570] 



SPECIES-BUILDIXG 



331 



the black border upon the hind wings possessed by 

 cccsonia; in the female, eurydice is clear yellow with no 

 dark border, while in cccsonia the female has a wide 

 border similar to that of its male, though less well marked 

 on the hind wings. The probable hybrid called amorplicc 

 is a female, intermediate in color between the typical 

 cccsonia and eurydice. That is, the border of ccesonia 

 crossed with no border (if my interpretation is correct) 

 is incompletely dominant. Wright says : 

 At one time I was of the opinion that AmorpJuz was a hybrid between 



is known, I have concluded that Amorphce is simply a dimorphic female 

 [of eurydice]. 



Possibly it is both, an example of dimorphism produced 

 either by immediate hybridization, or by a mutation re- 

 sulting from some previous hybridization. That a male 

 appears to be lacking in this case would not be an argu- 

 ment against the possibility of hybridization, for by such 

 crossing the sex ratio is frequently upset, the product 

 being of one sex only. But it appears to be possible that 

 the male of this cross is that described as M. bernardino, 

 a variety of eurydice found in the mountains of the same 

 region where amorphce also occurs. It is an interesting 

 combination of the male coloration of both species, having 

 the violet hue of eurydice that is lacking in cccsonia and 

 having the dark border of the hind wings of cccsonia lack- 

 ing in eurydice. Its female is described as being smaller 

 than that of eurydice, but otherwise practically identical 

 with it. This case, as Wright has suggested, is a most 

 inviting subject for further study, and, judging by what 

 he says of the sexual instincts of the eurydice male — " a 

 wooer . . . energetic and persistent, not hesitating to 

 ignore all rules of propriety, of species and of genera " 

 —not difficult of experimental management. 



The genus Basilarchia, the admiral butterflies, is well 

 known for the hybridization of its very unlike species, 

 B. arthemis the " banded purple " of the northern states. 



