378 EXTERNAL ANATOMY OF INSECTS. 
ropega or wing-socket *. It includes the Spzracula 
Scapularia. 
a. SprracuLa ScapuLaria (the Scapular Spiracles). 
Two spiracles observable, one in each scapular, in 
Pterophylla laurifolia, &c. 
C. MEsosterNuM (the Mid-breastbone). 'The elevated 
and central part of the Medipectus, between the mid- 
legs, often terminating anteriorly in amucro; some- 
times, as in Elater, in a cavity, receiving the mu- 
cro of the Prosternum ». 
D. Mepirurca (the Medifurca). A branching ertival 
process of the Endosternum, which serves as the 
point of attachment to the muscles that move the 
mid-legs °. 
E. Pepres InTerMeEpt! (the Mid-legs). The intermediate 
pair of legs, consisting of the same parts as the 
posterior legs 4. 
3.. MeraTHorax (the Metathorax). The posterior seg- 
ment of the Alitruncus*. It includes the Meso- 
phragma, Postdorsolum, Postscutellum, Postfrenum, 
Pleura, and Metaphragma. 
a. Mesopuracma (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‘. This, with the prophragm, forms the an- 
* Prates VILE. IX. o’. > Prater VIII. Fic. 4, 8, 13, 17. p’. 
© Pirate XXII. Fic. 6.9. % Pirate XVI. Fic. 4—6. 7”. 
Prate VILE. Fic. 3, 12. and IX. Fic. 1,7, 10, 11, 12, 15. 
Pirate XXII. Fic. 9, 11. s’. , 
Cc 
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