DISTRIBL'TJOX OF THE FAMILIES. 213 



provinces and to show the distribution of great groups in each of these. 

 But these great })rovinces rarely or never mark the separation of the more 

 important grou[)s of animals, such as tlie butterflies or the Lepidoptera as 

 a whole, but only limit the distribution of minor groups within these great 

 divisions. The butterflies, however, more perhaps than most other groups, 

 em2)hasize the grand division of the world into two great areas, the Old 

 and the New Worlds ; and it is only where, toward the arctic regions, the 

 fifreat lateral extension of the land brino-s the continental masses into 

 close juxtaposition, that we find any great similarity between the butterfly 

 faunas of these two vast regions ; and here in the nature of the case the 

 fauna itself is most scanty. When avc pass in the opposite direction 

 to the southern continents, widely separated from each other by vast 

 oceans, we find an almost total distinctness of fauna, so that a voyager 

 from one to the other region would be instantly struck by the quite different 

 aspects of butterfly life in the one region and in the other ; and as South 

 America is connected with the north by only a narrow peninsula, it stands as 

 the most distinct and unique butterfly region of the world, and the com- 

 plete or nearly complete confinement of some of the larger grou ps to this 

 continent is in entire conformity with the physical facts. 



Unfortunately, the study of the geogra^^hical distribution of butterflies 

 is not aided, as is that of many other groups of animals, by the data of 

 paleontology, but must depend entirely upon the knowledge of existing 

 forms. 



BIBLIOGRAPHY. 



Koch, G. Die geographiscbe verbreitung tier europaiscbe schmetterliiige iu anderen welt- 

 theileu. Leipzig, 1854. 



Speyer, A. uud A. Die geographiscbe verbreitung der schmetterliiige Deutschlands uiid 

 der Schweiz. Leipzig, 2 vols. 1858-1862. 



Koch, G. Die iiido-australische Lepidopteren-fauna in ihrem zusammenhang mit der euro- 

 paeischen nebst den drei hauptfauuen der erde. Leipzig, 1865. 



Kirby, W. F. On the diurnal Lepidoptera of the extra-tropical northern hemisphere. Dub- 

 lin, 1867 (Proc. Dubl. soc). 



Koch, G. Die geographiscbe verbreitung der schnietterlinge iiber die erde. Gotba, 1870 

 (Petermann's Geogr. mitth.). 



Kirby, W. F. On the geographical distribution of the dim-iial Lepidoptera as compared with 

 that of birds. Loudon, 1872 (Proc. Linn. soc). 



Hoft'mann, E. Die isoporien der europiiischeiitagf alter. Stuttgart, 1873 (Wlirtt. nat. jahresh.). 



Wallace, A. R. The geographical distribution of animals. New York, 2 vols. 1876. 



Gerhard, B. Ueber die geographiscbe verbreitung der 3Iacro-lepidoptera auf der erde. 

 Berlin, 1883 (Berl. eutom. Zeitschr.) 



Schatz, E. Die familien und gattuugen der tagfalter. Lief. 1. Fiirth, 1885 ( cf. p. 7-29). 



