556 E. N. FAVLOVSKY AND E. J. ZARIX 



Fig. 21. — Transverse section of rectal gland of a bee that has hibernated. 

 In the cells of its epithelium are visible numerous granular inclusions and 

 granules of secretion. Duboscq's fluid ; Heidenhain's iron haematoxylin. 

 Zeiss ; ,\ hom. imm., oc. 0. 



Fig. 22. — Oblique transverse section of rectal gland of a summer bee. 

 The network of deejily stained cell borders in which tracheae pass (fig. 25, 

 PI. 17) are visible. In the protoplasm of the epithelial cells there are no 

 inclusions. Zenker formol. Same stain and magnification as in fig. 21. 



Fig. 23. — Part of longitudinal section of the rectal gland. The entrance 

 of the trachea between the cells of its external layer and the formation of 

 lateral transverse branches of the trachea under the surface of the gland 

 are visible. Zenker formol ; iron haematoxylin. Zeiss ; ^\ hom. imm., 

 oc. 4. 



Fig. 24. — Network of tracheae under the surface of the inner wall of the 

 rectal gland. Same treatment. Zeiss ; ^.^ hom. imm., oc. 1. 



Fig. 25. — Part of surface section of the exterior wall of the rectal gland. 

 Tracheae running between the cells are visible. The surfaces of the latter 

 adjacent to them stain shari)ly l)lack. Same treatment and magnification 

 as in ])reparation no. 23. 



Fig. 26. — Cuticle of the epithelium of the small intestine with numerous 

 bacteria on its surface. Zenker formol ; Giemsa. Zeiss ; ob. ,^5, oc. 4. 



