44 INTERNAL ANATOMY OF INSECTS. 
and the prothorax, as in Blatta : in the Hcmiptcra and 
Netiroptera probably the situation is not very different. 
In the Lcpidoptcra this pair of spiracles is planted just 
before the base of the upper or primary wings a : a similar 
situation, I suspect, is appropriated to it in the Tric/io- 
ptcra, but covered by a tubercle or scale. Something 
similar has been noticed by M. Chabrier, in the same 
situation and circumstances, in the collar of Hjmeno- 
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 Lepidoptcrous, 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 % 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 
Orthoptera : — 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- 
custa, 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 Hcmiptcra in the parapleura 
a De Geer, i. 81. t. v.f. 10. /. b Sur le Vol des Ins. c. i. 459. 
c Reaum. iv. 24G. t. xix./. 8. s. 
ll 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". 
