Chapter 10 

 BUTTERFLIES 



The butterflies of Colorado are numerous and varied, in- 

 cluding many large and handsome species. How long they may 

 have existed in this region we do not know, but certainly for many 

 millions of years, since we find them fossil at Florissant. These 

 fossil butterflies all represent extinct species, and with one ex- 

 ception (Chlorippe wilmattae) are little related to those now 

 living in Colorado. The present-day butterflies of the Rocky 

 Mountains belong for the most part to what are called Holarctic 

 genera, that is to say genera found in the northern regions of 

 Europe, Asia and America. Indeed, certain of the species are 

 identical with those found in England. Every English butterfly- 

 collector hopes that sometime in his life he will have the great 

 luck to capture a specimen of the Camberwell Beauty (Euvanessa 

 antiopa). It was so called because it used to be found at Cam- 

 berwell, a suburb of London, now all built up and quite unsuited 

 for butterflies. It is a large broad-winged insect, on the upper 

 surface of a dark, rich chocolate color, and with a broad, pale 

 yellow border. Where the light border joins the darker color, 

 lilac-blue spots are set on a black ground. Both front and hind 

 wings have prominent angles or projections on the outer margin. 

 This butterfly, so rare and highly esteemed in England, is with 

 us a common object, and may be captured almost any day in 

 summer. It occurs in the mountains and foothills, and the very 

 spiny caterpillars may be found on the willow. The common 

 name for it in America is Mourning Cloak. To the biologist such 

 an insect is of special interest as representing a very conservative 

 type which has spread far and wide without changing its characters 

 or giving rise to a series of related species. Thus it contrasts 

 with Argynnis, the genus of Silver Spots, which includes so many 

 closely similar species and races that even the most learned 

 authorities are perplexed in dealing with it. A still more cosmo- 

 politan butterfly, also common with us, is the Painted Lady 

 (Vanessa or Pyrameis cardui). The wings are variegated with 

 black and rosy reddish in an intricate pattern, and near the apex 

 of the front wings may be seen a curved row of white spots on a 



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