98 SUPPLEMENT ON 



mass of species ; it is even almost total, if this aixh be 

 doubled, or consist of 24 degrees, as from the north of 

 Sweden to the north of Spain. 



Resting on these observations and some others less general, 

 M. Latreille separates, to the west, the two hemispheres, by a 

 meridian which, proceeding from Greenland, and following a 

 mean direction between the Canary Islands, those of Cape 

 Verd, Madeira, and the most advanced point to the east of 

 South America, Cape St. Roch, ends near Sandwich Land. 

 Its longitude is 34 degrees west of the meridian of Paris, 

 Another meridian more east by 62 degrees than that of that 

 city, detaches the oriental part of Asia from its western coun- 

 tries, from Europe, and from Africa. The difference of lon- 

 gitude of these two meridians is thus 96 degrees. A third 

 more eastern, and of the same quantity, will determine the 

 limits of the Old World and the New to the eastward, tra- 

 versing the great ocean. 



The other 144 degrees will complete the circle of the 

 equator, and will be in longitude, the extent of the grand 

 zone proper to the insects of America. M. Latreille divides 

 it by means of a fourth meridian into two equal portions, 

 having each ^2 degrees in longitude. 



These four great zones will be arctic, or antarctic, accord- 

 ing to their situation within, or beyond the equinoxial line. 

 M. Latreille divides each of them into climates to which he 

 gives twelve degrees of latitude. That which is comprised be- 

 tween 84 north latitude, and 72 degrees, is called the tropical. 

 Then, continuing the duodecimal division, come the following 

 climates : the sub-polar, superior, intermediate, sur-tropical, 

 tropical, equatorial. The antarctic zones, divided in the 

 same manner, have two climates less, the polar, and suh-j)olar, 

 since they terminate at the 60th degree of south latitude. 

 These zones considered in each hemisphere are distinguished 

 by M. Latreille, into occidental and oriental. 



