INTERNAL ANATOMY OF INSECTS. 39 



of Copris the corrugations form a perplexed labyrinth ; 

 in the caterpillar of the puss-moth the plaits are so nar- 

 row as to look like rays a ; and in some Dynastidce the 

 lips approach to a lamellated structure. Again, in Hy- 

 drophilus caraboides the upper lip, and in Dytiscus cir- 

 cumflexuS) both lips seem formed of elegant plumes b : a 

 similar ornament distinguishes the inner edge of the lips 

 in the caterpillar of the great goat-moth (Cossus lig- 

 niperda) and others c . In the grub of the rhinoceros- 

 beetle (On/ctes nasicomis) the margin of the lower or in- 

 ner lip is decorated by pinnated rays, which enter the 

 cellular membrane that covers the upper lip d : in this 

 larva, and that likewise of the cockchafer, the two lips 

 are formed of different substances; in the last the upper 

 or outer one consists of a perforated cellular membrane, 

 through which the air can pass, while the lower or inner 

 one is a cartilaginous valve that closes the orifice e : in 

 the former this valve is surmounted by a boss f . In the 

 pupa of Smerinthus Populi, a hawk-moth not uncommon, 

 and of some dragon-flies (Libellula depressa), the margin 

 of the two lips is crenated, probably with notches which 

 alternate, that the mouth of the spiracle may shut more 

 accurately s. The substance is unusually thick in the spi- 

 nose caterpillars of butterflies ; and in the pupa of one, 

 Uria Proteus, it is villose. 



Under the present head I may observe, that in some 

 cases, as in the puss-moth, and the larva of the common 



a Sprengel, 7. t. iii./. 30. b Ibid. t. ii./. 22. t. iii./. 29. 



c PLATE XXIX. FIG. 29. 



d Ibid. FIG. 10. Sprengel, Ibid. 9. /.I./. 46. 



c Ibid. 9. t. If. 9. ' PLATE XXIX. FIG. 16. a. 



8 Sprengel, Ibid. t. iii./. 27- 



