GEOGRAPHICAL DISTRIBUTION OF INSECTS. 4-97 



above or below the equinoctial line ; and taking twelve 

 degrees of latitude for each climate, he subdivides the 

 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 Jive, 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 subdi- 

 viding 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 a . In this chart of insect Geography he 

 states that he has endeavoured to make his climates agree 

 with the actual distribution of insects 5 ; 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* 



a Geographic, &c. <22-. b Ibid, 2?, 



VOL. IV, 2 K 



