THE CANADIAN ENTOMOLOGIST. Ill 



crossing would follow one form or the other, and tend to revert to the 

 parent or to become merged in the variety. Favorable conditions might 

 render one or more of them permanent, as with Alope Texana, which 

 seems to possess a territory of its own to the south-west. Certainly the 

 parent form would be more or less modified by the absorption of the 

 intergrades, if not permanently, yet so that now and then sports would be 

 thrown out in the direction of Alopc. Hence the two-eyed Pegala. That, 

 on the other hand, the intergrades nearest the strong variety would tend 

 to merge in it also, when cross breeding had ceased by the disappearance 

 of the parent form, we may infer from the fact that when Alope is sup- 

 pressed the tendency of the species is to the pure type Nephele. Wherever 

 Nephele is alone found there appear variations in the direction of Alope, 

 but they are very infrequent as compared with the typical form. 



Alope and Nephele are dimorphic in a certain belt of latitude which 

 embraces part of New York and New England, but as I have before 

 intimated, there is a longitudinal limit to the dimorphism also. Somewhere 

 between New York and Indiana Alope disappears. There would seem to 

 be a longitudinal belt of considerable width passing through western Ohio 

 and eastern Indiana, in which both forms are either unknown or of 

 extremely rare occurrence, while to the west of it Nephele Olympus 

 emerges in Illinois, Wisconsin, Iowa, &c. As before stated, Alope is 

 reported to be very rare at Cleveland (eastern Ohio), and unknown at 

 Toledo (north-western Ohio). In the region from Columbus (middle), 

 Dayton and Cincinnati (south-west), Alope and Nephele are unknown. A 

 line drawn from Toledo through Columbus to Cincinnati would embrace 

 about one third of the State. Dr. Landis kindly undertook to obtain 

 information for me from the collectors in eastern Indiana, and so far as 

 Indianapolis (a little to the east of the middle of the State) he reports 

 both forms unknown. It is true, collectors of butterflies are not numer- 

 ous, but they are usually very zealous, and each is likely to be well 

 acquainted with- his own neighborhood and for a considerable distance 

 around. 



I have recently had several letters calling my attention to published 

 lists of butterflies of different western States, in which Alope is mentioned 

 as present, and usually both Alope and Nephele. Such as Mr. Scudder's 

 list of butterflies taken by Mr. J. H. Allen, in Iowa, 1870 ; Mr. J. Duncan 

 Putnam's list of butterflies found about Davenport, Iowa ; Mr. Herbert 

 Osborn's recent list of butterflies about Ames, Iowa ; Prof. H. W. Parker's 



