EXTERNAL ANATOMY OF INSECTS. 379 



ropega or wing-socket a . It includes the Spiracula 

 Scapidaria. 



a, Spiracula Scapularia (the Scapular Spiracles). 

 Two spiracles observable, one in each scapular, in 

 Acrida laurifolia, &c. 



C Mesosternum (the Mid-breastone). The elevated 

 and central part of the Mcdipectus, between the mid- 

 legs, often terminating anteriorly in amucro; some- 

 times, as in Plater, in a cavity, receiving the mu- 

 cro of the Presternum b . 



D Medifurca (the Medifurca). A branching vertical 

 process of the Endosternum, which serves as the 

 point of attachment to the muscles that move the 

 midlegs c . 



E Pedks Intermedii (the Mid-legs). The intermediate 

 pair of legs, consisting of the same parts as the 

 posterior legs d . 



3. Metathorax (the Metathorax). The posterior seg- 

 ment of the Alitruncus e . It includes the Meso- 

 pkragma, Postdorsolum, Post scut ellum, Postfrcenum, 

 Pleurce, and Metaphragma. 



a Mesophragma (the Mesophragm). A partition of a 

 firm consistence, connected by its posterior margin 

 with the Postdorsolum, and passing down vertically 

 into the mid-chest; serving as a point of attach- 

 ment to several of the muscles that move the 

 wings f . This, with the prophragm, forms the an- 



• Plates VIII. IX. o'. b Plate VIII. Fig. 4, 8, 13, 17. p. 



c Plate XXII. Fig. 6. q . d Plate XVI. Fig. 4—6. r . 

 e Plate VIII. Fig. 3, 12.; and IX. Fig. 1, 7, 10, 11, \% 

 15. e. 

 s Plate XXII. Fig. 9, 11./. 



