THE CANADIAN ENTOMOLOGIST. 65 



DIFFUSION OF THE HAWK MOTHS IN NORTH AMERICA.* 



BY F. U. WEBSTER, URBANA, ILL. 



In the issue of Psyche for April, 1903, I published a paper on the 

 diffusion of insects in North America, in which reference was made in a 

 footnote to the probable trend of diffusion in the Sphingidas, and this may 

 be looked upon as supplementary to that publication. In the former 

 paper I could not deal with this phase of the problem of diffusion of 

 insects, to tiie extent that this family deserves, nor am I certain that this 

 is possible even now, but it seems desirable to point out some suggestive 

 features of the present distribution and probable diffusion of this interest- 

 ing family of moths. 



The Sphingida?, or Hawk moths, are noted for their stout, spindle- 

 shaped bodies, and for possessing the most powerful wings of all the 

 Lepidoptera, these last being long and slender, and provided with exceed- 

 ingly strong muscles, thus resembling those of sea birds. They are in this 

 way fatted for long flights, and are not infrequently driven by the winds 

 far out at sea, where they are encountered by ships long distances from 

 any land. They are primarily tropical insects, though they have become 

 widely diffused, have adapted themselves to almost frigid climates, and 

 are thus found throughout all the principal regions, except in New Zea- 

 land, where there is but a single form closely allied to, if not identical 

 with, the almost cosmopolitan Sphinx convolvidi, Linnaeus. That these 

 insects have existed structurally the same since a very remote period is 

 shown by the occurrence of an insect in Prussian amber that belongs to 

 this family, and has been referred to the genus Sphitix. The specimen 

 cited by Wallace as having been found in the Upper Oolite of Bavaria 

 seems to have been another insect and not one of the Hawk moths. 



We have in North America 82 species belonging to 31 genera. Of 

 these, 48 species, or more than one-half, are found in the eastern United 

 States, and 21 of these are known to occur southward through Florida and 

 in South America, while of the remainder many are known to extend 

 southward into Mexico. The 21 species have most assuredly reached 

 North America by way of what I have termed the Antillian trend of 

 diffusion. Of the remaining 26 of the 48 species, some few of them range 

 far enough to the west to indicate a diffusion from Mexico, or northward 

 through that country, though the majority of them are more or less closely 



*Read before Section F, American Association for the Advancement of Science, 

 3t. Louis, Dec. 29, 1903. 



