LICROSCOPIC AL ESSAYS. 



23S 



their fldn, which form a cone or cafe for the pupa. In thefe 

 the larva lofes firft it's length; the body becoming Ihorter, 

 aftumes the figure of an egg ; and the (kin forms a hard and cruf- 

 taceous cafe, or folid lodging, for the embryo infect. 



Of the Libellula. 



In the libellula, or dragon fly, we have an inftance of thofe in- 

 fects who are termed in the pupa ftate femicompleta, that is, who 

 proceed from the egg in the figure which they preferve, till the 

 time comes of alfuming their wings, and who walk, act, and eat, 

 as well till that period as afterwards. 



Of all the flies which adorn or diverfify the face of nature, * 

 there are few, if any, more beautiful than the libellula : " they ^ 

 are almofl of all colours, green, blue, crimfon, fcarlet, and r 

 white; fome unite a variety of the mod vivid tints, and exhibit, lV "'~*"^ 

 in one animal, more different fhades than are to be found in the 

 rainbow." The larva of the libellula is an inhabitant of the 

 water, the fly itfelf is generally found hovering on the borders 

 thereof. 



Thefe infects are produced from an egg which is depofited in 

 the water by the parent ; the egg fmks to the bottom, and re- 

 mains there till the young infect finds ftrength to break the flielL 

 The larva is hexapode, and is not quite fo long as the fly ; on 

 the trunk are four prominencies, or little bunches, which become 

 more apparent, in proportion as the larva increafes in fize and 

 changes it's (kin. Thefe bunches contain the rudiments of the 

 wings, which adorn the infect when in it's perfect ftate, 



6 * The 



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