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fiieath or cafe, A B D E being the cafe, and BCD the fting, M^hich 

 fting, he fays, is fo Iharp at the extremity, that he could not, with 

 his beft microfcopes, difcern the point. 



FJg. 7, reprefents the Iheath and the flings of the Gnat, as placed 

 by me before the microfcope, and drawn by the limner from the 

 life, by my diredlion, F G H I is the cafe or llieath, which the Gnat 

 opens on the fide, at G H I, in order to protrude the flings when 

 it is going to flrike : this llieath is covered with hairs, and between 

 them with many fmall feathers, but which feathers are fo clofely 

 joined to the body of it that they are rarely to be feen. H K is a 

 part of thofe four organs or flings, as they are regularly placed be- 

 fide each other, and at fuch a diflance from the Iheath as the Gnat 

 protruded them of its own accord, and not forced out by me, unlefs 

 in killing the animal I did it inadvertently. At K are feen the barbs 

 or hooks with which the flings are furniflied. The colour of thefe 

 flings is like that of tranfparent tortoifefliell. F I is that part of the 

 llieath and flings cut off next the Gnat's head. 



Fig. 8, LMNOP, reprefents that part of the fling, or fecond 

 cafe, from which I extracted the two other flings, the points of which 

 are furniflied with hooks. This has an opening from end to end, 

 through which the other flings may be protruded, in like manner 

 as I have mentioned refpeding the firft flieath : I have alfo, through 

 this opening, oftentimes drawn out all the three flings which lie 

 within it. 



L M Q O, is another piece, lying upon the former, and, being 

 fomewhat broader and longer than the other, feems as if defigned 

 to cover it like toother flieath, but I have often drawn it out of the 

 cavity of the piece LMNOP. 



Fig 0, RST, reprefents in part all the flings, and here may be 

 difcerned the two inward ones that are barbed, exhibiting the fame 

 appearance as at H K. Thefe two interior barbed flings are won- 

 derfully thin but not flat, for if fo they would, by their thinnefs, be 

 unable to bear any force, and flill lefs have power to perforate the 



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