CLASS-BOOK OF ZOOLOGY. 14^ 



some others have the form of Wasps, Bees, Hawk-moths 

 or Bugs. 



§ 626. Flies are of no direct use to man ; they are the 

 parasites of the Animal Kingdom. They torment man 

 and beast, by sucking their blood ; they spoil or destroy 

 our provisions ; their larva? destroy our meadows and 

 grain-fields, as the Hessian-fly ; while others make their 

 nests in the skin, brain, or stomach of animals. 



§ 627. The Musquito (Culex) is found in all parts of 

 the world, but differing in size and color, and everywhere 

 they are exceedingly troublesome. It is armed with a 

 proboscis, from which proceeds, as from a scabbard, a 

 very minute, fine sting, with which the insect pierces 

 the skin of its victim, and sucks its blood. 



5 628. The cause of the itching and inflammation pro- 

 duced by this sting, seems to be the saliva, which comes 

 from the proboscis, and enters the skin with the sting. 



§ 629. The Musquito lays about 300 eggs, in stagnant 

 water ; from which, after two days, proceed slender- 

 shaped larvas, moving in the water with great rapidity, as 

 we can see daily in open rain-casks. 



§ 630. After remaining only four weeks in the water, 

 the lame are converted into perfect insects. According 

 to this fact, five or six generations of the Musquitoes are 

 produced during one summer. 



§ 631. The Hessian-Jly, (Culex Destructor,) a species 

 of Musquito, was first seen in North America in 1776. 

 It is supposed that it was brought from Europe in a ship- 

 load of wheat, destined for the Hessian soldiers. 



§ 632. The Hessian-fly is very small ; entirely black, even 

 the wings, except at the root, where they are reddish- 

 brown ; feet pale, covered with black hair. 



§ 633. The female, in the spring, makes the stems of 

 wheat a place of deposite for her eggs, the maggots of 

 which enter the plant and feed on it. The number of 

 these insects is so immense, that they sometimes destroy 

 entire fields of wheat. 



5 634. The Gad-fly (Oestrus) lays her eggs upon 

 living animals, as Cows, Stags, Sheep, etc., by piercing 

 their skin with its strong and sharp ovipositor. 



