120 THE EMBRYOLOGY OF THE HONEY BEE 



deutocerebral lobes is given off a thin strand of nerve fibres, the 

 rudiment of the antennal nerve (Fig. 41, AntNv) which passes 

 laterad to the antennal rudiment (AntR). 



The tritocerebrum is in the larva, as in the adult, a rather ill- 

 defined region of the brain ; its two halves are virtually continuous 

 ventrad with the halves of the circumoesophageal commissures, 

 dorsad they are fused with the antennal lobes or deutocerebrum. 

 Each is united to its mate of the opposite side by a long and thin 

 band of nerve fibres, the suboesophageal commissure (Figs. 41 



StgNv 



Ao Oe(Flnt) 





mm 



SlkDO 



SoeGng 



FIG. 42. Transverse section through the posterior region of the head of 

 a newly hatched embryo (Stage XV), intersecting the optic lobes (iBr, 

 OpL), the suboesophageal ganglion (SoeGng), and the corpora allata 

 (Cor All), x 337. 



and 45, SoeCow), which passes beneath the oesophagus and in- 

 tersects the median plane between the oesophagus and the anterior 

 end of the suboesophageal ganglion. The two halves of the trito- 

 cerebrum are in addition connected with one another and with 



