THE TRIBE OF THE FRITILLARIES 131 



of this little butterfly. But perhaps enough has been said 

 to help us to understand something of the way in which 

 such insects are able to adapt their life habits to the con- 

 ditions of their environment. It is easy to see that if con- 

 ditions should so change as to give any one of these groups 

 a decided advantage over the others, the tendency would 

 be for the other groups to disappear and for the group of 

 favored habits to survive. 



The Meadow Fritillary is common in Canada and the 

 Northern states east of the Rocky Mountains. It is 

 found especially in lowland meadows and along the bor- 

 ders of swamps, the very situations chosen by the food 

 plants of the larva, the blue and the white violets. The 

 butterflies may be often seen sipping nectar from the 

 various species of mint and related plants found in such 

 situations. It is commonly associated with the Silver- 

 bordered Fritillary, from which it is easily distinguished 

 because it has no silver spots upon its wings. 



The Silver-bordered Fritillary 



Brenthis myrina 



This attractive little butterfly bears a close general re- 

 semblance to the Meadow Fritillary, from which it differs 

 chiefly by the continuous row of silver spots along the bor- 

 der of the under side of both pairs of wings. It is found 

 in the same localities as the other and its life-history is 

 very similar. 



The present species is widely distributed in North Amer- 

 ica, being found as far west as the upper Mississippi Val- 

 ley and the Rocky Mountains, and southward as far as 



