792 



MR. J. G. n. FRKW ON THE LARVAL 



triangular flap, and its distal end is produced downwards into 

 a sinular but more prominent ihip, the two flaps largely fdling 

 up the widened ends of the slit. The whoh? felted chatnber 

 with its branches is enclosed in a delicate, chitinons sbeathing- 

 membrane(s.')?i.). This membi'ano appears to be absent from the 

 extreme apices of the branches and does not, presumably, cover 

 over the openings. These two points could not, however, be 

 settled definitely. 



The Posterior S2nrades (text-figs. 7 tt 8) are situated at the- 

 apices of two very small stigmatic papillae carried postero-dorsally 

 by the last body-segment. Each pnpilla benrs at its apex a 

 rounded stigmatic plate (s.p.) in which are the three stigmatie 

 openings. Tlie postei-ior stigmata are of the same general type 

 as the interior ones. A bulb, which is, however, of no greater 



Text-ii"'ure 6. 



I'ostevior view of anteviov spiracle. 



diameter than the tracheal trunk, is interposed between the felted 

 chambor and the tracheal trunk. Its w'all is strengthened by twa 

 sinuous rid"es which may be se{)arate from each other, or the 

 proximal one may be incomplete with its ends fused with the 

 distal ridge as shown in text-lig. 7. I have not as yet seen a, 

 case where the distal ridge was incomplete. The felted chamber 

 is relatively narrow and long, with its walls produced internally 

 into delicate ridges and hairs; distally it divides into three very 

 short branches (not, however, all in one plane as are those of the 

 anterior stigmata), each of which opens on the stigmatic plate 

 by one of the openings mentioned above. In an apical view of 

 the stigmatic plate (text-fig. 8) a central dark area is seen caused 

 by lookii\g through the plate into the conical space betAveen the 



