A 06 



On the Entomology of the 



[July 



INFLUENCE OF TEMPERATURE AND OF MOISTURE. 



Ill those regions of the world where we find a multiplicity of genera of 

 animal^, united with a proliticness of species, we may natur.dly imagine 

 tbat circumstances are aihuirably suited to their existence ; and, on the 

 contrary, where we find a small number of genera, and in many instances 

 a diminutive form, and a paucity of individuals, we arrive at an opposite 

 conclusion. NoWj if we search for the cause of these discrepancies, we 

 shall find it to depend in a great measure on the intluence of tempera- 

 ture. Let us examine, then, in what portion of the globe a super- 

 fecundity of organized life exists. Certainly not at the poles, or even in 

 the temperate zones ; to the tropical and equatorial regions we must next 

 proceed, and it is there, in those warmer districts of the earth that we 

 find the energies of life more early developed, and vigour and produc" 

 tiveness seem the characteristics of the clime. These remarks apply 

 not less to animal than to vegetable life, for no where do the Herbivora 

 abound more than in warm regions, and no where do we meet with more 

 luxuriance of foliage, or a greater exuberance of arboreous vegetation, 

 than within the tropics. As we recede from the equator, and approxi- 

 mate to the poles, temperature gradually diminishes ; and probably nearly 

 in the same proportion as heat decreases, so shall we find the decrease of 

 animal and vegetable species, till we arrive at that degree of cold where 

 vegetation is stunted, circulation languid, animation becomes suspended, 

 and existence is scarcely tenable, if not actually destroyed. 



To obviate the effects occasioned by a low temperature, some animals 

 burrow in the eurth, and pass the winter in inactivity and torpor ; others 

 again, gifted with extraordinary locomotive powers, migrate into milder 

 regions in quest of food, which the rigour of a brumal season and a nor- 

 thern climate has rendered precarious. It appears to me an observation 

 worthy of attention, that at the very period the migratory birds visit us, 

 Insects are already teeming into life, while vegetation has arrived at a 

 state of forwardness sufl&cient to support, as it were, the expected in- 

 crease of animal beings. We infer, then, that as vegetation is apparently 

 regulated and influenced by temperature, so animalization is in a measure 

 dependent on vegetation as a secondary cause. It may naturally be ex- 

 pected, in a gigantic country like India, whose superficial area is nearly 

 one million and a half of miles in extent, that great diversities of climate 

 will be found ; and when we take into our consideration the altitude of 

 its mountains, surpassing in grandeur the Andes of the American world, 

 we may expect every gradation of temperature which can occur, from the 

 intense cold of the eternally snow-capped height, to the baneful heat of 

 the tropical valley. The elevation of the land above the ocean, the 



