388 Endocranium and Maxillary Suspensorium of the Bee. [May, 
principle of a machine recently patented for producing a slight 
and steady motion combined with strength.) The two parallel 
basi-cranial rods are also connected with each other by a very 
thin and pliable sheet of chitine, which forms the lower bound- 
ing wall of the head at the excavated part, and yet allows perfect 
freedom of motion to the suspensorial mechanism. 
The basi-cranial rods are forked at their distal ends, where they 
support the maxillary rami, one at each side (Fig. 5, MR), which 
are joined to them by avery perfect elbow-joint, enabling the 
rami to fold downwards. The rami support the maxille, which 
can thus be protruded or withdrawn. We think that each of 
these rami corresponds with the cardo or basal segment of the 
maxillz of the cockroach or beetle (though this name has been 
given to the process next to be described). 
The modus operandi of the maxille on these rami is note- 
worthy. Each maxilla consists of a flat base (stipe), surmounted 
by a lacinia resembling a knife blade, and bearing a rudimentary 
palp at the middle; and its lacinia can bend downwards and 
backwards so as to be out of the way and to present the stipe as 
a flat projecting plate. When the mouth parts are retracted, the 
two maxillz are thus bent down, and their plate-like stipes are— 
approximated, so as to forma hard under lip for the mouth, upon 
which the mandibles play in their operations (as on a piece of cork, 
or in cell-making as when the carpenter-bee is operating on wood). 
The basi and medi-labium then fill the excavated part of the basi- 
cranial surface. When the suspensorium is being protruded, the 
thin membrane which borders its proximal joints and which is 
extended so as to reach the blades of the maxilla, becomes tense 
and divaricates them so as to secure their steadiness of motion 
and to give free play to the intervening labium. 
From the distal end of the maxillary rami proceed two labial 
rami to support the labium, thus giving an additional joint, with 
a hinge which moves freely backward and forward. (This is the 
piece usually called cardo; we shall call it /adial ramus of the 
suspensorium, or labi-suspensorium.) By means of it a very 
1Dr. Hagen has shown us Wolff's article on “‘ Das Riechorgan der Biene”’ in 
Nowa Acta Leop. Carol., Band Xxxviil (1875), with beautiful and accurate drawings 
of the structure of the bee’s head. The author does not appear to have studied the 
parts in the relations here discussed ; and he is altogether fanciful in identifying the 
hard parts and the muscles of the bee’s skull with the bones and muscles of the 
mammalian head. 
