NYMTIIALIXAE: THE SPECIES OF AllGYNNIS. 553 



not doubled perhaps, but greatly increased. Nature seizes upon some 

 phenomenon in the life of each species and turns it to its advantage ; thus 

 in the European Brenthis, it seizes on the caterpillar's habit of hibernation 

 when half grown, and forces the spring brood of caterpillars at that point 

 in their growth to premature hibernation, in which some continue througli- 

 out the hot weather and until the following spring. Do not all these 

 strange phenomena, invariably looking toward the surer survival of the 

 species, point to something superior to the mere forces of evolution, con- 

 trolling and directing them? Surely, if hibernation be the pure result of 

 physical causation — and nothing seems simpler than that — where are the 

 physical causes that first produced premature hibernation in midsummer? 

 If it be said that this is subsequently induced through inheritance by the 

 habit of the alternating brood, we may ask : Why does not this occur in 

 Basilarchia, w^hich winters in the same stage, and in whose caterpillars of 

 the spring brood no such premature hibernation or sign of lethargy occurs ? 

 No, the deeper we look into these phenomena, the surer seem to be the 

 signs that the forces provoking the changes and characteristics observed, 

 are doing their work in no blind fashion, but rather under the impulse of 

 some controlling and thoughtful power. 



Table of species of Argynnis, based on the egg. 



Rugulose pits in interspaces separated from one another by about half their own width. Egg 



equally high and broad ; vertical ribs more than fifteen in number aphrodite. 



Rugulose pits in interspaces separated by much more than their own width. 



Egg distinctly higher than broad ; more than fifteen vertical ribs cybele. 



Egg of similar height and breadth; less than fifteen vertical ribs atlantis. 



Table of species, based on the caterpillar at birth. 

 Hairs not nearly so long as width of body. 



Their spicules inconspicuous cybele. 



Their spicules fully as long as half the width of hair aphrodite. 



Hairs fully as long as width of body atlantis. 



Table of species, based on the mature caterpillar. 

 Spinules not more than one-third as long as the spines, the latter orange luteous at base.. cybele. 



Spinules nearly half as long as spines, the latter pale livid at base atlautis. 



(Aphrodite unknown to me, but said to be slenderer than cybele.) 



Table of species, based on the chrysalis. 



6a.sal segments of abdomen particolored aphrodite. 



Basal segments of abdomen similarly colored in front and behind. 



Angle made by dorsal and ventral surfaces of front fourth of body about GO'-^ cybele. 



Angle as above, about 50*^ atlantis. 



(For best distinctions between aphrodite and cybele, see under aphrodite.) 



Table of species, based on the imago. 



The buff submarginal belt separating the two outer rows of silver spots on under surface of 

 hind wings broad. 

 Larger; on upper surface a blackish border only on anterior half of fore wings ...cybele. 

 Smaller; upper surface of all the wings with an unbroken or nearly unbroken blackish 



border, except on lower half of hind wings atlantis. 



The buff submarginal belt of hind wings, beneath, narrow aphrodite. 



70 



