ANTHOCARIS II. 



the larvae and chrysalids would best determine the relationship, but 1 have been 

 unable to find a description of these stages in Ausonia. It is to be noticed that 

 where a species becomes widely dispersed and sections are separated by impass- 

 able barriei's, the larvje are often first to differ, and may become quite distinct 

 before any wide difference is observed in the imago. As in the case of the Pa- 

 pilios, Turnus, and Enrymedon, where the butterflies differ but in color, while 

 the larvae are strikingly unlike. So with several of the Graptas figured in Vol. 

 I. of this work. And in determining the identity or otherwise of two forms 

 from opposite sides of the globe, especially if they inhabit the regions below the 

 Boreal, so that the segregation may be presumed to have been complete for a 

 long period, the preparatory stages are a most important element in the com- 

 parison. If the separation is marked in these, even though not clear enough in 

 the butterflies to be fixed by description — as, for instance, in the present case 

 of Ausonia and Ausonides — it is safe to conclude that on one or both sides 

 there has been a departure from the original type, and that henceforward be- 

 tween these two there will be nothing but divergence. They have reached a 

 point at which they may properly be treated as distinct species. 



