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INVERTEBRiTES. 



HoRSE-BOT The Horse-bot is the larva of a Hy rescmb/ing 



a humble-bee, with two wings. The female lays her eggs on the 



shoulders, manes, and knees 

 of horses, which they lick 

 oflF and swallow. They hatch 

 in the stomach, feed in the 

 larva state all the winter on 

 the mucilage, and in spring 

 are found in the horse's 

 stomach, sometimes in great 

 numbers. They resemble, in size and form, a date-stone, having 

 two hooks at the fore end, with which they adhere to the inner 

 coat of the stomach, often penetrating from one-fourth to half an 

 inch deep into the white insensible tissue, and become as if dis- 

 torted by it. If numerous, they cause violent pain ; and, as they 

 irritate the stomach, and extract a great deal of nourishment from 

 the animal, they necessarily injure digestion. 



Flies. — Of the Musca, or Flies, there are one hundred and 

 twenty-nine species, chiefly distinguished by the peculiiirity of 

 their feelers. 



The large Btiick Fly. 



