CONSIDKRATIONS. 475 



apertures, so as partly to cover the internal side of the coxce. 

 From this prolongation arises, on each side, a stout, broad, 

 but short apophysis, forming the second pair spoken of above. 

 These may be named the " anterior episternal apophyses.''' 

 Two small pieces placed within the thorax, and articulated to 

 the coxce, are called the rotulce. They are nearly triangular ; 

 very convex on the interior surface; the posterior margin is 

 straight, and articulated with the corresponding margin of the 

 opening of the coxa ; the opposite side is nearly circular, with 

 a small notch fitting a crescent-shape projection of the bouclier, 

 upon which these parts move; whilst at the same time they 

 fix indirectly the coxa to the bouclier. Two corneous rings, 

 of an elongate-oval form, suspended in the membrane, which 

 unites the prothorax to the mesothorax, near to the scuto- 

 sternal apophyses, surround the stigmata, and are termed the 

 " cadres des stigmates." 



The prothorax of Coleoptera varies much in different genera: 

 that of Forficula is intermediate between that of Coleoptera 

 on the one hand, and of the Lepismcc and Scolopendra on the 

 other; the upper part resembling the former — the lower, the 

 latter. Though differing much from the jirothorax of Coleop- 

 tera, it resembles it much more than that of the Orthoptera. 

 The structure of the legs is so well known, as to render it 

 needless for me to say more, than that our author uses the 

 terms commonly employed by French writers. 



The mesothorax is, in Coleoptera, generally one-half 

 smaller than the metathorax ; as the elytra, not being much 

 used in flight, do not require such powerful muscles as the 

 wings. It is composed of fourteen parts, besides several 

 small ones connected with the elytra, {proalce, Newman). 

 The upper surface consists of a triangular slightly convex 

 piece, {Vecusson) ; the anterior part of which is emarginate ; 

 but the emargination is filled by an almost membranous plate, 

 {le limbe de Vecusson). Another triangular plate occupies 

 about two-thirds of the anterior part of the lateral margin — is 

 directed downwards, and terminates in two slender apophyses. 

 This is called the " lateral apophysis " of the ecusson ; the 

 two branches are the anterior and posterior cornua, [comes 

 mittrieure et posttrieure). 



In some Coleoptera these are separated from the body of 

 the apophysis, and may then be called the " anterior scapulars." 



