larity of climate and temprature, have many insects 

 allied to each other in forms and habits ; but it will be 

 found, that differences exist among them sufficient to 

 prove that they could not have descended from a com- 

 mon stock, or in other words, that they are of different 

 species. Thus, of the tribe of butterflies, called by 

 the French brassicaires, because they are appropri- 

 ated to the cabbage, turnip, mustard, and other allied 

 plants, there is one sohtary species in the mountainous 

 and northern parts of New England devoted to these 

 plants.* The common cock-chaffer f of Europe is 

 represented, in this country, by our nocturnal dorr- 

 bug, t as it is usually called ; and the European vine- 

 chaffer II by an alhed species, H which has recently 

 multiplied greatly, from some unknown cause, and 

 threatens, if unchecked, to become as great a depre- 

 dator. It appears now to be pretty well established, 

 that countries, separated by a wide expanse of water, 

 by extensive deserts of sterile sand, or by an unbroken 

 chain of lofty mountains, possess vegetable and animal 

 productions pecuHar to themselves, which do not, 

 under ordinary circumstances, pass these natural lim- 

 its ; but that, wlien two continents, or great divisions 

 of the globe, are contiguous, or nearly approach each 

 other, the same animals and plants may be found in 

 each to a limited extent. No one species or kind 

 could have originated on two different points of the 

 earth's surface ; each one must have commenced exist- 

 ence in some one place, from whence, in the course of 



* It now attacks the turnip and cabbage, but probably lived originally 

 upon the Arahis rhomboidea. The insect is the Pontia oleracea. Harris. 

 f Melolontha vulgaris. F. | J\Ielolontha Qiiercina. Knoch. 



II Anomala Vitis. L. H Anomala varians. F. 



