ÉTAT ACTUEL DE LA QUESTION DU VEHICULE DE LA PESTE o7î 



sion anglaise décrit sous le nom de hypopharijnx (1), car elle est 

 placée sous le pharynx aspirant (%. 3, 4 et 6, lO) ; elle est « a chiti- 

 nous plate concave downwards, extending backwards from the 

 mandibulo-basal articulation to the subœsophageal ganglion. It 

 supports the salivary pump (fig., 9), the muscles for operating 

 which occupy its concavity. The dorsal convex surface is in rela- 

 tion with the under site of the aspiratory pharynx from which it 

 is separated by aspace; this 



is bridged 



by a liga- 



space 



ment (fig., 27), which divides 

 it into two parts, a posterior 

 (hœmocoel) and an anterior 

 (aspiratory canal). The ante- 

 rior margin at its centre is 

 prolonged into a pointed 

 process (fig. 4, 9), which 

 contains the exit duct of the 

 salivary pump. » 



The salivary pump (fig. 3, 4 

 et 6, 9) is situated medially 

 at the anterior end of the 

 under surface of the hypo- 

 pharynx. It receives the saliva 

 from the glands by means 

 of the salivary ducts(fig.. H) 

 and propels it through the 



exit duct of the pump into the salivary grooves in the inaudibles, 

 (tîg. 4 et 5) It is a hollow chitinous organ... Normally its cavity is 

 obliterated by the spring-like action of the chitinous walls, but the 

 muscles attached to the posterior wall when contracted cause a 

 lumen to appear which then becomes full of salivary sécrétion. On 

 the muscles relaxing the elastic reaction of the walls closes the 

 lumen and the sécrétion is expelled through the exit duct. The 

 opening of the salivary duct is in apposition with the salivary 

 canals in the mandibles (fig. 4 et o), which canals extend down 

 the mandibles. » 



(1| (le nom a été employé d'une manière erronée par Gerstfeld et Grube pour 

 désigner l'épipharynx. 



Fig. 2. — Pulex philippinensis Herzog 

 {P. cheopis Roth. ?). A cf , B extrémité de 

 la 9> d'après Herzog. 



