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, oi 

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

 allied to European forms. Subtracting 1 20 species as having been intrc 

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

 194 that have been introduced by "natural" means. The rest, 21 

 species, are endemic, though akin to European species. 



The scanty insect fauna of the Galapagos Islands includes twent; 

 species of Orthoptera, which have been studied by Scudder and by Sno< 

 grass. Five of these are cosmopolitan cockroaches, doubtless intrc 

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

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

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

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

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

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

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

 .has an apterous female. Apterous insects, noticeably common 01 

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

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

 islands, where the better-winged and more venturesome individuals ma; 

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

 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 ve] 

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

 no doubt; 352 species are at present known only from this archipelag< 

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

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



