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Distribution of Butterflies in the New World 



William Hovanitz 



Department of Biology, California Institute 

 of Technology, Pasadena 



1 he butterfly fauna of North America is proba- 

 bly better known than that of any other large group of insects. 

 The reason for this is clear: butterflies are day fliers and thus are 

 apparent to everyone. They are brightly colored and therefore have 

 been collected for non-scientific purposes, for collection hobbyist etc. 

 The result of this activity has been both advantageous and disad- 

 vantageous to the knowledge of the group from a scientific stand- 

 point. On the advantageous side is the tremendous job done by the 

 non-scientific or semi-scientific workers on ferreting out butterfly 

 haunts over the entire world and making this information available 

 in collections and the literature, so that the geographic distributions 

 of this group of insects is better known than that of any other. On 

 the disadvantageous side is the lack of organized study on the 

 butterflies due to lack of biological education by the hobbyists on the 

 one hand, and lack of much work by scientific workers created by 

 fear that work in this field will place them in the light of immature 

 or peculiar "butterfly collectors." 



Butterflies are a major evolutionary branch of Lepidoptera, 

 adapted to day-flying habits. It is not certain that the group as a 

 whole has had a common origin, or is therefore a natural group. It is 

 almost certain that the skippers (Hesperiidae) originated inde- 

 pendently. No data are given for the Hesperiidae because they are 

 not regarded as naturally related to the other families, even though 

 they have commonly been considered to be a part of the butterflies, 

 and because the taxonomy of the group involves special problems 

 that do not lend themselves well to this analysis. 



The families of butterflies other than the Hesperiidae are fairly 

 distinct, but appear to be closely related. All groups seem to have 

 had a past history of tropical origin. Since their body temperature 



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