226 NATURAL HISTORY. [CH. XV. 



place, the eg^s being protruded in the ordinary man- 

 ner, being of an oblong form, and forming, previous 

 to exclusion, two masses, arranged on each side of 

 the abdomen, each, however, being enclosed in a 

 delicate membranous sac, connected at one end with 

 that which is immediately in contact with it. Here, 

 however, we find nature still as fertile in her re- 

 sources as ever; these eggs, instead of remaining 

 for weeks or months unhatched, produce young in 

 a few hours : indeed, it is stated, that two hours 

 only are required for this purpose. 



It is not, however, for the purpose alone of keep- 

 ing down the accumulating masses of putrefying 

 animal matter, that the insects of the present order 

 are produced, since many feed upon hving animals, 

 as we shall more particularly notice in the following 

 chapter; while vast numbers are destined to put a 

 check to the occasionally too rapid progress of the 

 vegetable kingdom ; and it not unfrequently hap- 

 pens that, from the artificial state into which the 

 surface of the earth is brought by the process of cul- 

 tivation, and by the more extensive growth of pecu- 

 liar species of plants, that certain insects are pro- 

 duced in a corresponding degree ; which, while it is 

 of great detriment to the ajrriculturist and horticul- 

 turist, is probably but an instance of that 



" All partial evil, universal good," 



which pervades the workings of nature, or rather, 

 we should say, of Him who is the author of nature. 

 Thus, there are some species which employ their 

 destructive powers upon that chief source of our 

 daily support, the wheat, which, as soon as it blos- 

 soms, is immediately attacked by a small orange- 

 coloured midge (or gnat, as it has been miscalled), 

 of a very delicate form, which deposites its eggs 

 among the glumes of the florets of the wheat, by 

 the assistance of its ovipositor, which is very long 

 and retractile within the body, like the joints of a 



