890 



INVERTEBRATES. 



ORDER VI. — TWO -WINGED INSECTS. 



Insects of this order have only two wings, but beneath 

 them are balancers or poisers. Their mouths are frequently armed 

 with lancets and suckers, by means of which they pierce the skin 

 of animals, and feed upon their blood. To this order belong some 

 of the most troublesome and annoying of the whole animal crea- 

 tion, yiz., the various species of gnat and gad-fly, the mosquito, 

 the common house-fly, the horse-fly, etc. They attack both men 

 and other animals, and are found in almost every part of the globe. 

 Their larvse are deposited in the skins and intestines of brute 

 animals, sometimes even in those of men, in putrid meat, in 

 cheese, mud, and water. They pass through a complete meta- 

 morphosis. 



The Gnat. — The mouth is furnished with a fleshy pro- 

 boscis and two lateral lips. There are no less than one hundred 



The Qnat. 



and twenty-nine species, which arc chiefly distinguished by their 

 feelers. 



