1914.] NATURAL SCIENCES OF PHILADELPHIA. 545 



thus seen that the cells lie beneath the thinnest portion of the chitin 

 belonging to the posterior part of the articular membrane, and that 

 their exits lie in the thickest portion of this chitin. A transparent 

 area (Plate XIX, fig. 4, Amp) was seen in many of the cells, and a 

 tube (fig. 4, Tu) runs into each of these areas. 



In order to study these cells in a living state more carefully, the 

 articular membranes including the tissues adhering to them were 

 removed from worker bees. This material was placed on a slide 

 in a weak solution of methylin green. The cells adhering to the 

 chitin were teased apart and a few of them with their tubes were 

 separated from the mass of cells and chitin. Such a treatment, 

 however, almost always pulls the internal ends of the tubes out of 

 the cells, whereupon the transparent areas disappear immediately. 

 The tubes are then attached only at their peripheral ends. 



The cells vary considerably in size. They are either spherical 

 or ovoid in shape. Fig. 5 represents one of the largest ovoid cells. 

 It is typical and was drawn with the aid of a camera lucida while 

 still alive, being stained very slightly with methylin green. The 

 large nucleus has a heavy wall, and it stands out conspicuously. 

 The nucleoli with heavy walls stain green. The cytoplasm in the 

 centre of the nucleus has a faint green color, while that near the 

 periphery of the nucleus is semitransparent. The wall of the cell 

 is thin. The cytoplasm of the cell is more or less transparent. It 

 is granular and appears to have innumerable minute clear spots 

 (CIS). In the broader end of the cell lies the ovoid, transparent 

 area, which may be called the ampulla (Amp). The tube {Tu) 

 tejminates at the centre of the ampulla. The ampulla seems to have 

 many lines or streaks which radiate from the periphery toward the 

 centre, and these radial streaks (RadStr) stop short of the centre and 

 leave a perfectly transparent, ovoid area (TrA) at the centre of 

 the ampulla. 



Judging from the structure of these cells, we must call them 

 gland cells, but when observed hurriedly they may be mistaken for 

 oenocytes. As a rule, the oenocytes are smaller than the gland cells, 

 but nevertheless many of them are as large as many of the gland 

 cells. Only a few oenocytes may be found among the mass of gland 

 cells, but they are quite abundant on all sides of the gland cells- 

 Fig. 6 represents a typical large oenocyte, still alive and stained 

 slightly with a weak solution of methylin green. The following 

 may be used to distinguish a gland cell from an oenocyte. An 

 oenocyte is never connected with a tube. It never has an ampulla. 



