30 
THE HEAD OF THE BEE, 
and the liquid is drawn up ; but on pressing theni 
together, as in b (Fig. 13), two tubes {p d) are formed, 
whose capacity is much smaller than that of a, con- 
sequently the fluid is forced forward, just as it is in 
our own mouths. Bees are also able to distend the 
infolded membrane on the under side of the tongue 
and expose the rod, probably for the purpose of clean- 
ing it. 
In repose the mentum is drawn back, and the 
tongue (with the labial palps and covered by the 
maxillse) is folded back out of the way. 
