32 
BRITISH BEES. 
extending forwards, lienee takes several forms, usually 
tapering to an acute point, but sometimes rounded or 
hastate, according to the structure of the tongue, to 
which they form a protection. 
The maxillary palpi are small, longitudinal joints, 
never exceeding six in number, and generally in the 
normal or true bees not so numerous. They vary in 
relative length to the organ to which they are attached, 
and usually progressively decrease in length and size 
from the basal ones to the apical, but each joint, except¬ 
ing the terminal one, is generally more robust at its 
apex than at its own special base. The function of these 
maxillary palpi is unknown. They are always present 
in full number in the Andrenidce , and in some few 
genera of the true bees, but they vary from their normal 
number of six to five, four, three, two, and one in the 
latter; and it is curious that they are most deficient in 
those bees having the most complicated economy, as in 
the artisan bees and the cenobite bees; they thus evi¬ 
dently show that it is not a very parambunt function 
that they perform. On each side, at the apical summit 
of the labium, are inserted the labial palpi. These are 
invariably four in number, but vary considerably in 
length and substance. In the Andrenidce they have 
always the form of subclavate, robust joints, and are 
usually as long as the tongue, but not always; they are 
only half the length of that organ in the subsection of 
the acute-tongued Andrenidce. In the normal bees, 
even in the genus Panurgus, which is the most closely 
allied to the Andrenidce, the labial palpi immediately 
take excessive development, especially in their two basal 
joints, and the structure of these two joints, excepting 
in this genus and in Nomada, partakes of a flattened form 
