THE GNAT AND TIPULA. 165 



assistance of a microscope to distinguish the one 

 from the other : they are both mounted on long 

 legs, both furnished with two wings and a slender 

 body ; their heads are large, and they seem to be 

 hump-backed ; the chief and only difference there- 

 fore is, that the tipula w r ants a trunk, while the 

 gnat has a large one, which it often exerts to very 

 mischievous purposes. The tipula is a harmless, 

 peaceful insect, that offers injury to nothing ; the 

 gnat is sanguinary and predaceous, ever seeking 

 out for a place in which to bury its trunk, and 

 pumping up the blood from the animal in large 

 quantities. 



The gnat proceeds from a little worm, which 

 is usually seen at the bottom of standing waters. 

 The manner in which the insect lays its eggs is 

 particularly curious : after having laid the proper 

 number on the surface of the water, it surrounds 

 them with a kind of unctuous matter, which pre- 

 vents them from sinking ; but at the same time 

 fastens them with a thread to the bottom to pre- 

 vent their floating away, at the mercy of every 

 breeze, from a place the warmth of which is pro- 

 per for their production, to any other, where the 

 water may be too cold, or the animal's enemies 

 too numerous. Thus the insects, in their egg 

 state, resemble a buoy which is fixed by an an- 

 chor. As they come to maturity they sink deeper, 

 and at last, when they leave the egg as worms, 

 they creep at the bottom. They now make them- 

 selves lodgments of cement, which they fasten to 

 some solid body at the very bottom of the water, 

 unless, by accident, they meet with a piece of 



