GEOGRAPHICAL DISTRIBUTION OF INSECTS. 49 



intermixed with pines, or Liviodorce, Cacti, Passiflorce, Bigno- 

 nice, Lauri, Magnolia, and palms mingled with the northern 

 forms of oaks and firs, offer a landscape of unequalled variety. 

 In insects we find the same singular mixture ; and whilst many 

 of those of the United States so nearly resemble our own, as 

 at first sight to raise a doubt of their being distinct, others are 

 so lovely, so tropical in form and hue, that we find it difficult 

 to believe them inhabitants of a country where the winter frosts 

 impede the navigation of the rivers. 



The irregular distribution of heat over the surface of the 

 globe, and the variety of other causes which affect the develop- 

 ment of insects, forbid our dividing the globe into insect 

 climates, which are to extend over so many degrees of latitude 

 and longitude, as proposed by Latreille, who, after objecting to 

 the divisions of Fabricius, as artificial and vague, proceeds to 

 divide the globe into certain divisions, each of which is to be 

 considered as a peculiar insect climate. 



He commences by separating the globe into three portions : 

 the first dividing line extends, from pole to pole, in long. 31° 

 W. ; the second is nearly identical with the 66th eastern 

 meridian; and the third with the 175th western. Thus we 

 have three great divisions : one, containing Europe, the 

 Azores, Iceland, part of Greenland, Africa and its islands, 

 and the western part of Asia. The second comprises the 

 middle and east of Asia, the great continent of Australia, and 

 some of the isles of the Pacific. The third division, including 

 all America, the Sandwich, Society, Friendly, and part of the 

 Marquesas Islands, is divided into equal portions by a line 

 nearly corresponding with the 106th meridian. "^ 



These are again divided by lines parallel to the equator, and 

 distant from each other IS*' of latitude. Beginning at lat. 

 84° N. and 60° S. we shall thus have twelve climates for each 

 of the great divisions ; namely, seven Arctic, and five Antarctic, 

 distinguished by the terms, equatorial, tropical, supra-tropical, 

 intermediate, superior, subpolar, and polar ; the two last only 

 in the Arctic climates. These are again divided at every 

 24th meridian. Without remarking on the impropriety of 



•> In converting the longitudes into our own way of reckoning them, I have 

 allowed only 2° for the difference in longitude between Paris and London. This 

 is not quite enough, Paris being 9 min. 21'6sec. east of Greenwich. 

 NO. I. VOL. II. H 



