ANALYSIS. 519 



That plants, which have no means of changing their place, 

 except by foreign agency, should be confined to certain di- 

 stricts, is perhaps to be expected. At least, this circumstance 

 is not calculated to excite our astonishment so much as, that 

 beings endued very perfectly with the powers of locomotion, 

 should never wander beyond certain definable limits. Whe- 

 ther, indeed, the species be thus in a manner imprisoned 

 within an invisible wall, or whether their non-appearance 

 beyond certain degrees of latitude be owing to the circum- 

 stance that those which may have strayed so far from their 

 assigned region immediately perish, — in either case, no 

 more convincing instance of the geography of animals be- 

 ing definite, can be advanced than G. pilularius. We 

 find this insect in the north of France, and, according to 

 SchasfFer, at Ratisbon ; also, according to Pallas, in that 

 tract of country which separates the Don from the Wolga : 

 and again, if this celebrated naturalist be right as to the 

 identity of the species, it occurs in the north of Chinese 

 Tartary, on the banks of the Selenga. A learned Entomolo- 

 gist, M. Gebler, whose residence in the heart of Siberia is 

 rendered tolerable by the study of Natural History, has 

 also sent me the G . Jiagellatus from Barnaul. Latreille, 

 therefore, appears perfectly accurate when he fixes the 

 northern geographical limit of Gi/mnopleurus at the 50th 

 degree of latitude, since this parallel is so strictly the boun- 

 dary of that species which comes the furthest north. But 

 do the minimum and maximum heights of the thermome- 

 ter remain constant throughout the old world on this pa- 

 rallel of latitude ? If they do not, we may suppose that the 

 geographical distribution of these animals has been regu- 

 lated by some other principle besides warmth. Our know- 

 ledge of the economy of the Gi/mnopleurus assures us also, 



