496 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 3 . 
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 
* Latr. ubi stipr, 3. 
