382 EXiJSxv^AA. ANATOMY OF INSECTS. 



C Metaphragma (the Metaphragm). A nearly verti 

 cal septum or partition, attached behind to the 

 Postfrcenum, and usually deeply cleft at its apex in 

 Coleoptera, of a rather horny consistence, which 

 forms the upper separation of the second cavity of 

 the Alitrunk from that of the Abdomen*. It affords 

 a point of attachment for many muscles of both 

 alitrunk and abdomen. It includes the Septula. 

 a Septula (the Septula). The lesser ridges and par- 

 titions raised on the surfaces of the metaphragm, 

 and on those of other parts of the cavities of the 

 trunk, serving as points of attachment to various 

 muscles b . 

 4. Postpectus (the Postpectus). The underside of the 

 second segment of the alitrunk c . It includes the 

 Mesostethiwn, Parapleurce, Metasternum, Postfurca, 

 Opercula, and Pedes Postici. 

 A Mesostehium (the Mesostethium). A central piece 

 between the intermediate and posterior legs, and 

 bounded laterally in Coleoptera by the Parajrteurce 

 — along the middle of which, where it exists, the 

 Metasternum runs d . 

 B Parapleur^e (the Parapleural). Two pieces, one on 

 each side of the Postpectus, included between the 

 Scapularia, Mesostethium, and Pleura e . They in- 

 clude the Spiracida Parapleuritica. 

 a Spiracula Parapleuritica (the Parapileuritic Spi- 

 racles). Two spiracles, one in each of the Para- 

 pleurce of Tetyra f . 



* Plate XXII. Fig. 10, 11. x . b Ibid. Fig. 9—11./". 



c Plates VIII. and IX. /. d Ibid. j/. 



e Ibid. z. i Plate XXIX. Fig. 15. *". 



