EXTERNAL ANATOMY OF INSECTS. 371 
with the Dorsolum, which passes down into the an- 
terior cavity of the alitrunk, of which it forms the 
upper separation from that of the manitrunk. It 
affords a point of attachment to several muscles of 
the wings, &c. ? 
C. Dorsotvum (the Dorslet). The piece which lies be- 
tween the Collare and Scutellum, to which the pro- 
phragm is anteriorly attached, and which bears the 
upper or anterior organs of flight®. It includes 
the Pteropega, Elytra, Tegmina, Hemelytra, Ale 
Superiores, and Tegule. 
a, Preropreca (the Wing-socket). The space in which 
the organs for flight are planted. That for the se- 
condary or under-wings is in the Metathorar<. 
b. Exyrra (the Elytra). The upper organs for flight, 
when they are without nervures, and uniformly of 
a thicker harder substance than membrane whether 
corneous, or coriaceous ; lined by a fine membrane; 
and when closed, united by the longitudinal suture‘. 
They include the Axis, Sutura, Epipleura, Alula, 
and Hypoderma, and are peculiar to the Coleoptera 
and Dermaptera. 
A, Axis (the Azzs). A small, prominent, irregular pro- 
cess of the base of the Elytrum, upon which it turns, 
and by the intervention of which it is affixed to the 
Dorsolum, in the anterior wing-socket ¢. 
B. Sutura (the Suture). The conflux of the sutural or 
* Prate XXII. Fie. 8, 11. 2’. 
» Ibid. Fic. 8. VIII. Fie. 3, 12, 14,16. IX. Fic. 1,7, 8,10—12, 
15, 19, 21. 7. 
* Peate VIII. Fic. 14, 20. IX. Fre. 11, 12. and XXII. Fie. 8. 3". 
¢ Pirate X. Fic. 1. and XXVIII. Fic. 1—8, 10. 
© Prats XXVIII. Fic. 3—5. 8”. 
2 ES 
