DISTRIBUTION OF ANIMALS. 573 



of different species. Those occupying the eastern parts of Asia ai - e distinct from those 

 met with in Europe and Africa under the same parallels of latitude ; and a similar differ 

 ence is observable upon comparing the entomology of the old and the new continents, 

 though both have species in common, while Australia presents forms peculiar to itself. 

 It is in the torrid zone of the earth, where the air is humid and the vegetation rank, that 

 we have the most intense, splendid, and at the same time annoying, development of insect 

 life. By day, in countless numbers, and adorned with the richest colours, butterflies 

 sport in the sunbeams ; and by night the tropical forests are illuminated by the green 

 light of myriads of fire-flies a family which includes the glow-worm of our climate, 

 most brilliant when disturbed and irritated which give to the woods the appearance of 

 a natural Vauxhall. "It is snowing butterflies!" was the remark of a seaman of the 

 Beagle when off the coast of South America ; for flocks consisting of many myriads 

 extended as far as the eye could range ; nor, with the help of a telescope, could a space 

 be discovered free from their presence. As the atmosphere was perfectly calm, they had 

 evidently left the shore upon a voluntary excursion. But in these countries several of 

 the insect races are a source of severe suffering to the human inhabitants, on account of 

 their venomous qualities, their immense swarms, the pertinacity with which they assail 

 the person of man, or their rapacity in consuming the fruits of the earth. The spider of 

 Guiana will even singly attack birds with success : and the termites, or white ants of 

 India and Africa, will penetrate the beams of houses ; destroy timbers, chests, books, and 

 clothing in a few hours ; or, by excavating beneath the dwellings of the inhabitants, 

 render them insecure. Though only about a quarter of an inch in length, they erect 

 pyramids to the height of ten or twelve feet, sufficiently compact to sustain the weight of 

 several men, dividing them into numerous apartments far more wonderful works, in 

 proportion to the size of the animal architect, than the pyramids of Egypt. The mus- 

 quitoes by day, succeeded a little before sunset by the tempraneroes, and the zancudoes 

 by night, are, however, the most painful and unceasing scourge of man in the torrid zone 

 of America. They are rarely found on the elevated table-lands, but in the valleys, as 

 well as in most places along the coasts, the lower stratum of the atmosphere is frequently 

 so completely occupied by them to the height of twenty feet, as to assume the appearance 

 of a dense cloud of vapour. It is a remarkable feature of their distribution, that while 

 they avoid dry and unwooded situations, and chiefly haunt the banks of rivers, they shun 

 those streams which have what the Spaniards call black waters, aguas negras, or water 

 of a yellowish-brown colour. Insect life is also rife in high latitudes, the heat of the 

 short polar summer calling forth in the arctic region of Greenland and Lapland an army 

 as innumerable as the heat of the equator, and of an analogous annoying species. 



Several of the insect races are eminently gregarious, associate in numbers utterly inap 

 preciable, and unitedly migrate under the influence of some casual pressure, the quest of 

 food. Hence the vast armies of the eastern locust, Gryllus migratorius, which from time 

 immemorial have been regarded as an avenging scourge, stripping large territories of 

 every particle of verdure, and passing on in a dark and overwhelming cloud to blast the 

 expectations of the husbandman, whose fields are preparing for the harvest. A Jewish 

 imagination illustrates the havoc to be apprehended from the advance of a reckless 

 oriental conqueror, by a reference to the disasters consequent upon an invasion of this 

 insect tribe : 



" For a nation liath gone up on my land, 

 Who are strong and without number ; 



They have destroyed my vine, and have made my fig-tree a broken branch, 

 They have made it quite bare, and cast it away ; the branches thereof are made white. 

 The field is laid vraste ; the ground, the ground mourneth 1 



