THE EMBRYOLOGY OF THE HONEY BEE 131 



Nbl 



'Hyp 



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FIG. 49. Transverse sections through developing ventral cord. A, 

 region between the first and second thoracic segments, Stage IX; B, first 

 mandibular segment, Stage X; C, first thoracic segment, Stage X; D, 

 posterior region of second thoracic segment, Stage X, x 600. 



especially since the ganglion cells are very similar to those of 

 the mesoderm. 



