326 ENTOMOLOGY 



interruption of local life may have caused." (Scudder.) Probably 

 many species were exterminated and many others became greatly modi- 

 fied, though little is known as to the relationship of the present fauna to 

 the preglacial fauna. "The glacial cold still lingers over the northern 

 part of this continent and our present animals are only a remnant of 

 the rich fauna that existed in former ages, when the magnolia and the 

 sassafras thrived in Greenland." 



Island Faunae. The ability of insects to surmount barriers, under 

 favorable circumstances, is strikingly shown in the colonization of 

 oceanic islands. Not a few insects, including Vanessa cardui, have 

 found their way to the isolated island of St. Helena. In the Madeira 

 Islands, according to Wollaston, there are 580 species of Coleoptera, of 

 which 314 are known to occur in Europe, while all the rest are closely 

 allied to European forms. Subtracting 120 species as having been intro- 

 duced probably or possibly through the agency of man, there remain 

 194 that have been introduced by " natural" means. The rest, 266 

 species, are endemic, though akin to European species. 



The scanty insect fauna of the Galapagos Islands includes twenty 

 species of Orthoptera, which have been studied by Scudder and by Snod- 

 grass. Five of these are cosmopolitan cockroaches, doubtless intro- 

 duced commercially, and the remaining fifteen are all " distinctly South 

 and Central American in their affinities." Three of these fifteen are 

 strong- winged species which doubtless arrived by flight from the neigh- 

 boring mainland; indeed, Scudder records a Schistocerca (S. exsul) as 

 having been taken at sea two hundred miles off the west coast of South 

 America, "or nearly half way to the Galapagos Islands. Thirteen of the 

 fifteen are endemic, and five are apterous or subapterous, while a sixth 

 has an apterous female. Apterous insects, noticeably common on 

 wind-swept oceanic islands, may have been carried thither on drift- 

 wood, though it is more likely that the apterous condition arose on the 

 islands, where the better- winged and more venturesome individuals may 

 have been constantly swept out to sea and drowned, leaving the more 

 feeble-winged and less venturesome individuals behind, to reproduce 

 their own life-saving peculiarities. 



The Coleoptera of the Hawaiian Islands, studied by Dr. Sharp, num- 

 ber 428 species, representing 38 families, and "are mostly small or very 

 minute, insects," the few large forms being non-endemic, with little or 

 no doubt; 352 species are at present known only from this archipelago. 

 Dr. Sharp distinguishes three elements in the fauna: "first, species that 

 have been introduced, in all probability comparatively recently, by arti- 



