110 THE CANADIAN ENTOMOLOGIST. 



Alope and the rest there are two ocelli, not always complete or equal, and 

 occasionally one is suppressed. When this happens it is always the lower 

 one, which is wanting in Pegala. There is a tendency to variation in the 

 number of these ocelli, a second one sometimes appearing in Pegala, but 

 a third one sometimes in Alope, and in the last named species and the rest 

 of its sub-group, there are not unfrequently one or two small spots on the 

 fore wings, as of incipient ocelli. The single ocellus invariably seen at 

 anal angle in Pegala is often wanting or incomplete in the other forms ; 

 and the six ocelli of under hind wing, almost invariably present (but 

 sometimes six on one wing, five on the other — never less, so far as 

 observed), vary from six to nil in all the others. 



The fact that the area now occupied by Pegala is so restricted shows 

 that the present conditions are not favorable to it. One can understand 

 that in former times, since these Satyrids had possession, the conditions 

 geologic and climatic may have been quite different from what they now 

 are, and that Pegala may have occupied a much enlarged area, while Alope 

 inhabited parts of the same, or indeed originated with Pegala precisely 

 as Nephele has originated with Alope. In this last case there would have 

 been a series of intergrades between Pegala and Alope, caused by the inter- 

 breeding of the variety and the parent form. 



If in the northern belt the conditions were to become unsuited to the 

 support of any Satyrus, and the forms which now occupy it were suddenly 

 to become extinct, we should have to the south Alope, and to the north 

 Nephele, two good species. The intergrades would have wholly disap- 

 peared, or there would be a wide gap in the series, and nothing would be 

 left to show how one form could have originated with the other. Alope 

 and Nephele would then occupy a position similar to that of Pegala and 

 Alope now. What might happen by some sudden change of conditions 

 might also happen gradually and come to the same end. If a certain 

 variety, Alope, thrown off by Pegala, flourished in its larval state on 

 meadow grasses rather than coarse saw grass or sea-side grass, then its 

 tendency would be towards the country which produced the former, and 

 there would be a movement to the north and north-west. At the same 

 time there would be a withdrawing of the parent form from the borders of 

 the original territory, because there the food plant was not in perfection, 

 and so a belt would come to intervene between the parent and the variety. 

 The former would flourish where its food plant flourished, which in this 

 case would be the sea-board. The intergrades which had arisen from 



