THE H YPOPHA R YNX 



77 



In the fleas the hypopharynx is a large, slender, unpaired, long, 

 chitinous trough, as long as the mandibles, and toothed at the end. 

 Figures 79 and 80 show its relations to the other parts of the mouth ; 

 in Fig. 79, x, is seen where the salivary duct opens into the pharynx. 

 Although this organ is not unanimously referred to the hypopharynx, 



B 



mx 



mx.p 



FIG. 79. A, hypopharynx of Pulex c-aiii* : 

 as, basal portion situated within the head ; s. d, 

 common duct of the four bladder-shaped sali- 

 vary glands ; 8. d', opening of the tubular sali- 

 vary glands into the throat. , end of the 

 hypopharynx, showing the gutter-like structure 

 and teeth at the end. After Landois. 



- -mx.p 



md hi/p 



FIG. 80. Beak of Vermipsylla : hyp, hypo- 

 pharynx. After Wagner. 



yet from the description of Landois and others, it is evident that 

 this structure does not correspond to the labrum or epipharynx, but 

 belongs to or arises from the floor of the mouth, and, being in close 

 relation to the labium, and also receiving the salivary duct, must be 

 a true hypopharynx. 



