RECTAL RESPIRATION 



465 



Eaton states that there is a rectal respiration in the nymphs of 

 may-flies, and Palm en observed in young larvae of Baetis and Cloeon 

 that the rectum took 

 in " by gulps " water 

 colored by carmine and 

 expelled the whole of 

 it at once, in order to 

 fill it again in the same 

 way. " This rectal res- 

 piration therefore cor- 

 responds to that of 

 Libellulid larvae." 



Besides breathing by 

 spiracles, by tracheal 

 gills, as well as through 

 the integument, the 

 larva of Culex has been 

 observed by Raschke 

 to have a rectal respira- 

 tion. At the anterior 

 end of the rectum arises a countless number of fine tracheae, which 

 pass through the walls and, subdividing, end in numberless very 



FIG. 484. End of the body of the same larva as in Fig. 

 431, seen from the side, the branches of the main tracheae 

 (Mr) omitted : Kbl, excrementitial pellet in rectum ; kl>, 

 tracheal gills ; b, funnel of the closing apparatus ; hz, hollow 

 tooth of the closing apparatus ; Tc, fc t , k a , siphonal lobes ; th, 

 tactile hair ; as, chitinous plate ; str, rudder ; I, its thickened 

 edge; sch, its shank; s', a",W&t\es. This and Fig. 433, 

 after Raschke. 



VF 



FIG. 435. Thorax and anterior abdominal 

 segments of the nymph of a may-fly (Cloeon 

 tlimidiatum) with tracheal gills J(tK lt tk,, tk^ 

 and the rudiments of the fore wings (VF) 

 and hind wing (IIF) : tl, tracheal longitudinal 

 trunks. After Graber, from Lang. 



FIG. 436. Gills on the middle abdominal 

 segments of larva of cetis binoculatus : trl, 

 longitudinal tracheal trunks ; vf, stigmatic 

 cord ; ktr, gill-tracheje ; trk, tracheal gills. 

 After Palmen, from Lang. 



fine twigs in the papilla-like folds situated within the rectum. The 

 supply of tracheal twigs is greatest where the papillae are largest. 

 (Figs. 433, 434.) 



2H 



