THE EMBRYOLOGY OF THE HONEY BEE 



concerned. Petrunkewitsch (1902) has published a figure il- 

 lustrating a transverse section through a drone egg during the 

 stage of mesoderm formation in which is shown a distinct roll- 

 ing up of the edges of the middle plate while still attached to 

 the lateral plates. This condition tends to approach the type 

 found in Chalicodoma, and if it normally exists in the drone 

 could be readily interpreted as intermediate, connecting types 

 i and 2, as illustrated by Chalicodoma and Apis respectively. 



MP 





FIG. 22. Longitudinal (sagittal) sections through the anterior region 

 of the germ band, Stage V, showing segmentation. A is a section along 

 the mid-line, and includes only the middle plate; B is lateral of the 

 mid-line. The mesoderm is here now divided into two layers, x 387. 



