THE EMBRYOLOGY OF THE HONEY BEE 143 



(VIII) is actually composed of cells of just this character (Fig. 

 52, Ant). If these groups of small cells represent the antennal 

 rudiments, then the antennae originate caudad of the future 

 mouth, since its location on the germ band is marked by the point 



Hyp 



iBr, 



NIG 



FIG. 52. Transverse section through the head of an embryo, Stage IX, 

 showing the three principal divisions of the brain (iBr, zEr, sBr). and the 

 antennal rudiment (Ant), x 387. 



where the cells of the anterior mesenteron rudiment come to the 

 surface. 



At Stage VIII the procephalic lobes have undergone considera- 

 ble change both in position and form. The entire germ band has 

 increased in length, thereby bringing its anterior end around the 

 cephalic pole of the egg, so that the procephalic lobes are now 

 curved in a semicircle, their anterior ends lying on the dorsal 

 side of the egg and directed toward the caudal pole. The 

 procephalic lobes have meanwhile become subdivided into 

 three lobes, the three pairs constituting respectively the proto- 

 cerebrum, deutocerebrum and tritocerebrum, each of which rises 



