138 
Beekeeping 
The proboscis consists of the external mouth parts other 
than the mandibles (Fig. 68, Prb, Fig. 72, A-H). This 
group of organs serves in taking up liquid food. The name 
“tongue” is usually given to the slender median portion 
( Gls) but is loosely applied to the three median parts, the 
labrum. Snodgrass {l.c. pp. 44-45) explains the relation 
of these parts to the mouth parts of other insects and points 
out the true homologies, at the same time showing the 
errors into which various writers on bee anatomy have 
fallen. The accompanying illustration (Fig. 72, A-H ) 
shows the structure of the organs of the proboscis. It 
will be seen (Fig. 72, D) that there are three terminal pieces, 
the central glossa {Gls) and two lateral labial palpi ( LbPlp ) 
arising from the mentum {Ml), a median basal sclerite, 
and two maxillae, arising from separate basal pieces, the 
stipes {St). These in turn articulate with the lorum {Lr), 
a flexible band connecting with the cardines {Cd) which 
attach the whole proboscis to the head at the fossa of the 
proboscis {PrbPs, Fig. 68, B), on which it is suspended. 
The maxillae {Mx) are articulated by the cardines {Cd) 
to the maxillary suspensoria on the side walls of the fossa 
while the mentum {Mt) articulates with the submentum 
{Smt) which is held in the lorum {Lr). These parts are 
suspended in the membrane in the fossa floor, giving great 
freedom of movement. 
The glossa {Gls) is covered with circles of hairs and the 
tip (labellum, Lbl) is spoon-shaped. The tip is protected by 
spiny hairs {Hr), formerly supposed to be taste organs, between 
which is the end of the ventral groove {k) of the glossa. 
When the proboscis is not in use the labium and maxillae 
are folded back against the mentum and stipes. When 
in use, these parts are unfolded and held together. In 
sucking liquid the base of the labium slides between the 
bases of the maxillae. To acquire this motion, the sub¬ 
mentum turns on the lorum and the mentum turns on 
its articulation with the submentum. This gives the men¬ 
tum a forward and backward movement and the labium 
