■894-J 
337 
[Packard. 
the reason that it is united with the head and i)liarynx in the 
same way as the labruni of Diptera, and because, like the labrura 
of Diptera, it assists in the work of sucking, since it completes 
the back of the sucking tube, being curved down on each side of 
it. Moreover the mandibles on each side contain a deep furrow 
in which the two outlets of the salivary glands open. I have 
before shown that two ducts of the salivary glands in Vermip- 
sylla, which lie in the basal portion of the abdomen, unite near 
the head into a single efferent duct which first passes into the 
pliarynx and then goes into the unpaired j^iercing organ. Since 
I do not suppose that Vermipsylla is an exception to other fleas, 
I think that Kraepelin has not seen 
this salivary duct. Moreover, with- 
out entering into the mode of attach- 
ment of the unpaired piercing organ, 
I see in the very fact that the common 
efferent duct of the salivary glands 
passes into the piercing organ, a deci- 
sive proof against the view that it is 
the labrum. Landois (p. 27) also 
speaks of a common duct passing oiit 
from his 'bladder-like salivary gland,' 
which must enter the pharynx, but 
which he had not traced so far. 
Should we bring this statement into 
harmony with the view of Kraepelin, 
then must we adopt the view that 
the piercing organ represents two 
parts : the labrum and the hypopha- 
rynx (epipharynx) ?" It may be ob- 
served that Wagner entiiely agrees 
with Kraepelin as to the nature of the labium, though he differs 
both from Taschenberg and from Kraepelin in reoardino- the 
fleas as "a very specialized group of Diptera." 
Our own scanty observation on this organ, made mostly from 
examination of a slide of the flea of the European hedgehog {Pulex 
erinacei Bouche, Fig. 23), shows that it agrees with the figure of 
Landois (Fig. 19). At its base within the head it divides into 
two separate rods {stili hypopharyngi, st) which protect the end 
of the efferent duct. In the specimen drawn, the base of the 
Fig. 22. Eucl of mandible 
of Vermipsylla, highly mag- 
nified : t, teeth.— After Wu(/- 
ner. 
PUOCEEDINGS H. S. N. 11 
