Packard.] 
348 
[May 2, 
liyjiopliaryiix is the fact that it encloses the end of the salivary 
duct. This shows that it is an outgrowth of the 2d maxillae or 
labium. The type of beak of the Siphonaptera, then, seems on 
the whole to be more like that of the Diptera than that of any 
Other order of sucking insects, the resemblance being seen in the 
presence of a hypopharynx and of a lalnum, while the composi- 
tion of the beak differs remarkably in the absence of a labrum. 
Fig. 31. Oesophagus (oe), pharynx (ph) with epiphar3'ux (q^/i), and 
labrum (Ibr) of Asihts atricapillus ; mph, pharyngeal muscle; sr, salivary 
receptacle; other lettering as in Fig. 30. — After Meinert. 
Hence I am unable to agree with Kraepelin that the piercing 
organ is the labrum, and I coincide with the view of Wagner 
that it cannot be that part. 
The Sij^honaptera, then, differ from 
the Diptera, as respects the beak and 
its accessories, in the lack of a clypeus 
or hypostoma, and of a labrum, while 
tlie mandibles are large and well devel- 
oped, adapted only for piercing the flesh, 
being serrate on each side. The max- 
illae also are well developed, consisting 
of an acute, broad, blade-like piercing 
lobe, with a 5-jointed palpus stretched 
out like an antenna, while the labium 
is represented by a minute basal portion 
apparently giving origin to the hypo- 
FiG. 32. Hypopharynx 
of Stomoxys stimulans ; p, 
posterior, a, anterior part 
of the hypopharynx; s, 
styles of the labrum. — 
After 3Ieinert. 
