334 
[May 2, 
In Palexcanis, according to Landois, the hypopharynx, together 
with the mandibles, situated on eacli side of it, forms a closed 
suckin<r tube. 
Fig. 19. A, hypopharynx of Pulex cauls ; x, basal portion situated with- 
in the head ; s.d, common duct of the four bladder-shaped salivary glands ; 
s.d', opening of the tubular salivary glands into the throat; B, end of the 
hypopharynx, showing the gutter-like structure and teeth at the end. — 
After Landois. 
As the result of his transverse sections of the flea's beak, 
Kraepelin was led to deny the existence of a hypopharynx in 
Siplionaptera. He states his belief that the hypopharynx, present 
in all Diptera, is in the Pulicidae entirely wanting. "This absence 
of the hypopharynx results in a wholly different use of the 
mandibles and the formation of a very peculiar tyjjc of sucking 
