4-96 GEOGRAPHICAL DISTRIBUTION OF INSECTS. 



groups or species appear, may be regarded as fixed by 

 the will of the CREATOR, rather than as certainly regu- 

 lated by any isothermal lines. Still, however, under 

 certain limitations, it must be admitted that the tempe- 

 rature has much to do with the station of insects. The 

 increase of caloric is always attended with a proportional 

 increase in the number and kind of the groups and 

 species of these beings. If we begin within the polar 

 regions of ice and snow, the list is very meager. As we 

 descend towards the line, their numbers keep gradually 

 increasing, till they absolutely swarm within the tropics. 

 Something like this takes place in miniature upon moun- 

 tains. Tournefort long since observed at the summit of 

 Mount Ararat the plants of Lapland; a little lower, those 

 of Sweden ; next, as he descended, those of Germany, 

 France, and Italy; and at the foot of the mountain, such 

 as were natural to the soil of Armenia. And the same 

 has been observed of insects. Those that inhabit the 

 plains of northern regions have been found on the moun- 

 tains of more southern ones ; as the beautiful and com- 

 mon Swedish butterfly Parnassius Apollo, on the moun- 

 tains of France, and Prionus depsarius on those of 

 Switzerland a . 



M. Latreille, having given a rapid survey of the 

 peculiar insect-productions of different countries, next 

 attempts a division of the globe into climates, which he 

 thinks may be made to agree with the present state of 

 our knowledge, and be even applicable to future disco- 

 veries. He proposes dividing it primarily into Arctic 

 and Antarctic climates, according as they are situated 



a Latr. ubi supr. 3. 



