HISTORY OF INSECTS. 3 



the blue-bottle fly must be known to many; the silk- worm's 

 eggs again are not unknown ; but the generality of insects* 

 eggs are so concealed, and so little conspicuous, that they 

 are found with difficulty. Examples of larva are numer- 

 ous; the maggots found in wasps' nests and used in fishing, 

 the maggots in apples and nuts, the maggots in cheese, 

 and in decaying substances, and the caterpillars which 

 devour our cabbages, and those which spin webs on our 

 apple, pear, and plum trees, are familiar to us all : these 

 are insects in the larva state. The pupa state is more dif- 

 ficult to find, because insects generally crawl away into 

 crevices or hide themselves underground, before changing 

 to this state ; an angular pupa, of a green colour, with small 

 black spots, which produces a common white butterfly, 

 may, however, be frequently seen on palings and garden 

 walls, and the smooth brown pupas of moths axe continually 

 dug up in gardens. The imago, or perfect state, is exem- 

 plified in butterflies, moths, gnats, flies, wasps, bees, ants, 

 beetles, grasshoppers, earwigs, cockroaches, bugs, fleas, 

 may-flies, and dragon-flies. All descriptions of insects in 

 scientific works relate to the imago state, unless the con- 

 trary is distinctly expressed. 



The mode in which the life of an insect is passed, differs 

 very widely in the various states of its existence : it often 

 happens that the larva inhabits the water and the imago the 

 air ; sometimes the larva inhabits the water, the pupa inha- 

 bits the earth, and the imago returns to the water. The 

 following brief histories will in some degree exemplify this. 



History of the Simulia.* The eggs of the Simulia 

 or sandfly (sometimes also called the mosquito], appear to 

 be at present unknown ; there is, however, little doubt, that 

 like those of other gnats, they are deposited on the surface 



* Authority; M. Fries, in ' Entomologisches Archives.' 



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