NATURAL HISTORY. 139 
. Linneus has only eleven forts of thefe Flies, namely, the water Flie, 
the Summer Flie, and the Cherry tree Flie; thefe have variegated. 
Wings : the dung hairy Flie, the wonderful Flie, the putrid Flie; and 
the Flie of the neceflary houfe: thefe three have variegated bodies: the 
£lephants trunk Flie: the Heth Flies the houfe Flie, and the Flie that 
8 bred in cheefe, 
Oy dbs Be ea Hg tells 
OF THE GNAT AND TIPULA, 
(From Goxpsmiru.) 
HXHSRE are two infe&s which entirely refemble each other in 
their form, and yet widely differ in their habits, manners, and 
Propagation. Thofe who have feen the tipula, or long-legs, and the 
arger kind of gnat, have moft probably miltaken the one for the other, 
they have often accufed the tipula, a harmlefs infe&, of depredations 
Made by the gnat, and the innocent have fuffered for the guilty; in- — 
deed the differences in their form are fo very minute, that ic often re 
Quires the affiftance of a microfcope to diftinguifh the one from the 
ther: they are both mounted on long-legs, both furnifhed with two 
Wings and a flender body; their heads are large, and they feem to be 
lump-backed ;_ the chief and only difference, therefore, is, that the 
Upula wants a trunk, while the gnat has a large one, which it often 
€xerts to very mifchievous purpofes. The tipula is a harmlefs peace- 
fal infed, that offers injury to nothing; the gnat is fanguinary and 
Predaceous, ever feeking out for a place in which to bury its trunk, 
*nd pumping up the blood. from the animal in large quantities. 
he gnat proceeds from a little worm, which is ufually feen at the‘ 
Ottom of ftanding waters. The manner in which the infeét lays its 
Ses is particularly curious ; after having laid the proper number on the 
Urtace of the water, it furrounds them with a kind of un@uous matter, 
Which prevents them from finking; but at the fame time faftens them 
With a thread to the bottom, to prevent their Hoating away, at the mercy 
®t every breeze, from a place the warmth of which is proper for their 
Produgion, to any other, where the water may be too cold, or the ani- . . 
Mals its enemies too numerous. ‘Thus the infects, in their egg flates _ 
Tefemble a buoy, which is fixed by an anchor. As they come to ma~ 
‘urity they fink deeper, and at laft, when they leave the egg as worms 
‘Ney creep at the bottom. ‘hey now make themfelves lodgments of 
“ement, which they faften to fome folid body at the very bottom of 
ms water, unlefs, by accident, they meet with a piece of chalk, which 
Sing of a foft and pliant nature, gives them an opportunity of finking 
Tetreat for themfelves, where nothing but the claws of a cray-fifh 
fan poffibly moleft them. The worm afterwards changes its form. 
“ appears with a large head, and a tail invefted with hair, and moif- 
"ded with an oleaginous liquor, which the makes ufe of as a cork, to 
» fuftain 
