44 INTERNAL ANATOMY OF INSECTS. 



and the prothorax, as in Blatta : in the Hemiptera and 

 Neuroptera probably the situation is not very different. 

 In the Lepidoptera this pair of spiracles is planted just 

 before the base of the tipper or primary wings a : a similar 

 situation, I suspect, is appropriated to it in the Tricho- 

 ptera, but covered by a tubercle or scale. Something 

 similar has foeen noticed by M. Chabrier, in the same 

 situation and circumstances, in the collar of Hymeno- 

 ptera b . In numerous Diptera this breathing pore is 

 planted on each side between the collar and the dorso- 

 lum above the arms c , and in Hippobosca in the collar 

 itself d . 



In Lepidopterous, Coleopterous, and some other larvae, 

 the two segments of the body corresponding with the 

 alitrunk in the perfect insect, are without spiracles, nei- 

 ther have they in this state, though pneumatic organs 

 have been discovered e , any real ones in that part : but 

 not so the remaining orders, all of which have these or- 

 gans in that section of the trunk. To begin with the 

 OrtJioptera : in Blatta there seems to be a long narrow 

 one behind the intermediate leg ; in the Gryllotalpa there 

 is one in the posterior part of the pleura ; and in Lo- 

 cust a, above both the intermediate and hind legs f . It 

 is probable, that in general those that have no spira- 

 cles in the manitrunk have four in the alitrunk, which 

 seems the natural number belonging to the trunk. In 

 many of the Heteropterous Hemiptera in the parapleura 



De Geer, i. 81. t. v./. 10./. b Sur le Vol des Ins. c. i. 459. 

 c Reaum. iv. 246. t. xix./. 8. s. 



d In this tribe, which I forgot to remark before, (see VOL. III. 

 p. 549 .) there seems both prothorax and collar. 

 VOL. III. p. 550, 559. &c. 

 f PLATE VIII. FIG. 14. h". 



