GEOGRAPHICAL DISTRIBUTION OF INSECTS. 485 
whole into twelve climates. Beginning at 84° N. L. he 
has seven Arctic ones, which he names polar, subpolar, 
superior, intermediate, supratropical, tropical, and equa- 
torial: but his antarctic climates, as no land has been 
discovered below 60° S. L., amount only to five, be- 
ginning with the equatorial and terminating with the 
superior. He proposes further to divide his climates 
into subclimates, by means of certain meridian lines ; se- 
parating thus the old world from the new, and sub- 
dividing the former into two great portions,—an eastern, 
beginning with India, and a western, terminating with 
Persia. He proposes further that each climate should 
be considered as having 24° of longitude, as well as 12° 
of latitude?. In this chart of insect Geography he 
states that he has endeavoured to make his climates agree 
with the actual distribution of insects®; and it should 
seem that in many cases such an agreement actually does 
take place: yet the division of the globe into climates by 
equivalent parallels and meridians, wears the appearance 
of an artificial and arbitrary system, rather than of one 
according with nature. 
He has also pointed out another index to insect cli- 
mates, borrowed from the Flora of a country. Southern 
forms in Entomology, he observes, commence where the | 
vine begins to prosper by the sole influence of the mean 
temperature; that they are dominant where the olive is 
cultivated ; that species still more southern are compa- 
triots of the orange and palmetto ; and that some equa- 
torial genera accompany the date, the sugar-cane, the 
indigo, and banana‘. ‘The idea is very ingenious, and, 
* Géographie, &c. 22—. » Jbid, 27. © Tbid, 20— 
