AKCTIC BUTTERFLIES CLARK 289 



ward in the mountains to New Mexico. Here they are represented 

 by four different species with about a dozen forms. The species 

 found in North America scarcely differ from others found in Asia. 



In the Parnassians the flight of the males in the hot sunshine 

 is easy and graceful. They progress by flapping and irregularly 

 sailing with many turns and twists, stopping from time to time to 

 feed on flowers with the wings expanded. They fly rather near the 

 ground and rather hurriedly, and if it suddenly turns cold or rainy 

 they take refuge in the herbage where their large size and white 

 color makes them conspicuous. The females are less active than the 

 males, and have a more clumsy and more fluttering flight, though 

 when it is cold the males fly in the same awkward and hesitating 

 manner as the females. 



Some Parnassians have a curious habit of drifting irregularly up 

 a valley in the morning, and down again in the afternoon. In the 

 high altitudes at which they live exertion becomes difficult. One 

 cannot chase a butterfly without very soon becoming distressed. But 

 this curious habit makes their capture easy. On the mountain side 

 above the town of Chamounix in France I found a shallow valley in 

 which the finest of the European species {Parnassius apollo) was 

 unusually common. From a seat on a stone high up in the middle of 

 this valley I could see the butterflies zigzagging irregularly upward, 

 flying back and forth across the valley as they came. As they ap- 

 proached I could judge about where they would pass in their diag- 

 onal flight and, by walking a few paces up or down, could easily 

 intercept and capture them. If they are frightened they may make 

 off at a very creditable pace, and then pursuit is all but hopeless. 

 When depositing their eggs the females fly low with a curious slow, 

 hesitating flight, and frequently alight upon the food plant. As a 

 rule they are not shy, and are easily followed up and caught. 



Although nearly all of the parnassians are mountain butterflies, 

 a few are found on the northern plains. They can withstand the 

 most rigorous conditions on the high mountain peaks of central 

 Asia and of Colorado, but none of them lives as far north as the 

 Arctic regions. The farthest north that any has been found is 

 Viliusk (lat. 63° 35' N.) in the valley of the Lena River. Here 

 Parnassius tenedius has been taken. This is not very far away from 

 Verkhoyansk, the " cold pole " of the world, in the valley of the 

 adjacent Jana River. One of the common European species {P, 

 mnemosyne) ranges almost as far north. 



The butterflies of the far north and those of alpine regions are 

 very variable from place to place and run into many puzzling forms, 

 largely as a result of living in relatively small colonies in more or 

 less widely separated localities. In the mountains the individuals of 



