332 1NSECTA. 



are folded in two directions, or simply in their length, and the inner 

 margins of the cases, usually coriaceous, are crossed. They only expe- 

 rience a semi-metamorphosis. 



In the seventh or the HEMIPTERA, there are six legs and four wings, 

 the two superior in the form of crustaceous cases, with membranous 

 extremities, or similar to the inferior, but larger and firmer; the man- 

 dibles and jaws are replaced by setae forming a sucker, enclosed in a 

 sheath composed of one articulated, cylindrical, or conical piece, in the 

 form of a rostrum. 



In the eighth or the NEUROPTERA, there are six legs, four mem- 

 branous and naked wings, and mandibles and jaws for mastication ; 

 the wings are finely reticulated, and the inferior are usually as large as 

 the superior, or more extended in one of their diameters. 



In the ninth or the HYMENOPTERA, there are six feet, and four 

 membranous and naked wings, and mandibles and jaws for mastication ; 

 the inferior wings are smaller than the others, and the abdomen of the 

 female is almost always terminated by a terebra or sting. 



In the tenth or the LEPIDOPTERA, there are six legs, four mem- 

 branous wings, covered with small coloured scales resembling dust ; a 

 horny production in the form of an epaulette, and directed backwards, 

 is inserted before each upper wing, and the jaws are replaced by 

 two united tubular filaments, forming a kind of spirally convoluted 

 tongue. 



In the eleventh or the RHIPIPTERA, there are six legs, two mem- 

 branous wings folded like a fan, and two crustaceous moveable bodies, 

 resembling little elytra, situated at the anterior extremity of the 

 thorax ; the organs of manducation are simple, setaceous jaws, with 

 two palpi. 



In the twelfth or the DIPTERA, there are six, legs, twomembranous 

 extended wings, accompanied, in most of them, by two moveable 

 bodies or halteres, placed behind them ; the organs of manducation are 

 a sucker composed of a variable number of setae inclosed in an inar- 

 ticulatcd sheath, most frequently in the form of a proboscis terminated 

 by two lips. 



