32 THE ANATOMY OF THE HONEY BEE. 



entoskeleton and are individually called apodemes. Those of the 

 head constitute the entocranium, those of the thorax the entothorax. 



The side walls of the fossa of the proboscis form two high, thin, 

 vertical plates, as seen from the interior of the head (fig. 11), in 

 front of the mesocephalic pillars. The posterior edge {d) of each 

 of these plates is so much thicker than the rest of it in the worker 

 that it appears at first sight to be a separate rod. Its upper end 

 projects above the body of the plate as a free arm (e) to which is 

 articulated the basal piece of the maxilla {Cd). It thus constitutes 

 the maxillary suspensorium. (Macloskie includes under this term 

 both the arm of the cranial wall and the cardo of the maxilla.) 



The head of the drone (fig. 11 B) presents, besides the parts de- 

 scribed, a thin plate (/) depending from the vertex of the cranium 

 along the line between the compound eyes. 



Besides these apodemes of the cranial wall itself there are others 

 which project into the head cavity from the bases of the appendages 

 to afford points of insertion for their muscles. These are specially 

 developed in connection with the mandibles and will be described in 

 the discussion of these organs. Still other internal chitinizations are 

 developed in the walls of the pharynx, but these likewise will be 

 described later. 



2. THE ANTENNiE AND THEIR SENSE ORGANS. 



The antennae of the bee are the two slender, jointed appendages- 

 movably attached to the center of the face, where each is inserted 

 into a circular membranous area or socket just above the upper part 

 of the clypeal suture. Their general shape and position are shown 

 by figures 9 A, 11 A, and 19, Ant. Each is seen to consist of two 

 parts, forming a prominent elbow with each other, and usually so 

 held that the first or proximal part extends outward and upward 

 from its frontal attachment and carries the other in a pendent posi- 

 tion from its distal end. The first part thus forms a basal stalk, 

 called the scape (figs. 9 A; 19, Scp)^ consisting of a single joint 

 inserted into the antennal socket of the front by a prominent basal 

 condyle bent toward the face. This articular knob is attached to 

 the rim of the socket by a circle of membrane, but it is also pivoted 

 on a slender peglike process projecting upward from the lower edge 

 of the socket. Hence, while the flexible membrane allows each 

 antenna to revolve freely in any direction, the latter is at the same 

 time held firmly in position by the pivot. The antennae are moved 

 by special sets of muscles inserted upon their bases within the head. 

 The second or distal division of the antenna is cylindrical and longer 

 than the first, forming a flexible flagellum, (fig. 9 A; 19, FT) hanging 

 downward from the distal end of the scape. It is composed of 11 



