1 9(i 



PSyCHE. 



iMav, iqoi 



Yet this very weakness is probably 

 one cause of the ability of this species 

 to maintain its hold in its peculiar 

 dwelling-place ; for the study of the 

 insects of wind-swept regions, like 

 oceanic islands and high mountain sum- 

 mits, shows us that to maintain their 

 life the inhabitants must be either spe- 

 cially strong-winged to withstand the 

 gales, or very weak-winged, or, indeed, 

 often wingless, so as not to attempt to 

 contend against the wind, or even to be 

 quite unable to fly. 



So our weak-winged Semidea rarely 

 takes flight at all in windy weather, or, 

 if caught by a gust, makes no attempt 

 to cope with it, satisfied if it be allowed 

 speedily to drop into some sheltered 

 spot where it may secure a foothold. It 

 then proceeds forthwith to creep into 

 some cranny ; or, if still prevented by 

 the wind, falls over upon its side, 

 feet to the windward, but clinging 

 to the rock or soil, closes its wings, 

 and tucks them together so as to 

 offer the least surface to the dangerous 

 breeze. Our illustration (plate i ) repre- 

 sents one thus clinging to a stone, a bit 

 of lichen-covered rock brought for the 

 artist's use from Mt. Washington ; it 

 shows, also, as well as can be shown with- 

 out color, how the exposed mottled por- 

 tions of the butterfly's wings harmonize 

 with the freckled surface of the rock, — 

 a case of " protective resemblance." 



So it maintains its hold. And cer- 

 tainly not with difficulty, for it is one of 

 our commonest butterflies ; and though 

 hundreds, perhaps thousands, are an- 



nually captured by enthusiastic collec- 

 tors, mostly within an area of a single 

 square mile, it continues as abundant as 

 ever, and seems better able than the 

 wide-ranging bison to avoid extinction. 

 During the entire month of July the 

 butterflies swarm over the rocks and 

 sedgy plateaus of the upper summits, 

 directly through which thousands of 

 travellers yearly make their pilgrimage 

 by the cog-railway or the carriage 

 road. 



During the latter part of this month 

 hundreds of thousands, perhaps mil- 

 lions, of eggs are laid by the butterflies, 

 from which, in about a fortnight, hatch 

 big-headed, striped mites of caterpillars ; 

 these nibble at the sedges a short time, 

 and then, their parents long dead, go 

 into winter quarters, hiding in the neat- 

 est crevices they can find. 



Probably the whole of the next sum- 

 mer and part of still another is spent in 

 this stage, in which the caterpillar feeds 

 both by night and by day upon the 

 sedges, that so abound upon the moun- 

 tain-side as often to give the appearance 

 of a pasture ground. 



Some, doubtless, mature sooner than 

 others, or we should see the butterfly 

 only in alternate years, whereas it is 

 equally common every year. When not 

 feeding, the caterpillar is hiding between 

 the rocks in just such places as it 

 chooses to pass the winter in, and where 

 also it changes to a chrysalis, lying 

 flat upon its back without further protec- 

 tion than the rocks afford ; unless, in- 

 deed, it cuddles up against some moss. 



