176 Mr. W. S. xMacLeay on the Anatomy of the 



to the stigmata of the scutellum of the metathorax.* Perhaps these are 

 Mr. Kirby's par op/eztrffi. 



4. The epimera are large, connecting the scutellum with the meta- 

 sternum, and passing from the episternum to the postscutellum.j- Mr. 

 Kirby seems only to have noticed these pieces under the peculiar form 

 they adopt iu Tettigonia, where he calls them opercula-X 



Applying the above philosophical nomenclature to certain insects, which 

 have hitherto been considered anomalous, we shall get some remarkable 

 results. Let us take, for instance, Stylops McUttce.^ We find the puz- 

 zling appendages to the scutum of the mesothorax to be true elytra, and 

 that consequently the only wings the insect possesses are the under wings, 

 the paraptera of which are enormously developed as well as the epimera 

 of the metathorax. This insect, in fact, ceases to be so very extraor- 

 dinary.|l 



Having now detailed this symmetrical theory of the thorax, I may 

 apprize the reader that my future descriptions shall be adapted to it. M. 

 Jurine, in his valuable paper on the wings of Hyvienoptera, says their 

 thorax is composed of thirty-six pieces. Considering, however, the 

 clavicle of M. Chabrier and the sqnamula to belong to the wing, there 

 are only the following pieces according to Audouin, viz. 



• Fig. 5 and 10, N. f Fi?- 5 and 10, M. 



X See " Rapport fait a I'Acad. des Sciences, &c., 19 Fevrier, 1821." p. 7. 



§ Having' no specimen of the Stylops with me, 1 am here alluding to Mr. 

 Bauer's figure of it in the Linnean Transactions, and allowance ought accord- 

 ingly to be made for my not here speaking from actual dissection. From M. 

 Jurine's beautiful dissections of Xenus Vesparum it appears that the StTejtsiptera 

 differ from each other considerably in structure. 



|] In the same way Evania ceases to have its abdomen very singularly situ- 

 ated on this explanation of its anatomy. The scutellum and postscutellum of 

 the metathorax in this genus being confluent, and the postscutellum, never- 

 theless, excessively developed, the abdomen appears inserted on the back of 

 the insect. It is, however, in its proper place. 



