SACBROOD. 



the cut surface of the older ones shows the presence of a varying num- 

 ber of old cocoons (fig. 2, C). Near the mouth of the cell on the side 

 walls (figs. 1 and 2, C) will often be noted a wrinkling of the surface. 

 This wrinkling is caused by the presence of old cocoons. The two 

 remaining walls are parallel and will be referred to as the lateral 

 walls (fig. 1, L). The bottom is concave on the inside. The cap 



Fig. 3.— End view of cell capped. The cap is 

 convex, being recently constructed. (Origi- 

 nal.) 



is also concave on the inside, making 

 it convex on the outside. 



When freshly constructed the sur- 

 face of the cap (fig. 3) is smooth and 

 and entire and shows considerable 

 convexity. Later, not infrequently 

 it is found to be less convex and 

 somewhat irregular. The cap should 

 remain normally for the most part 

 entire (fig. 8) . While this is the rule, 

 there are exceptions to it. The bee- 

 keeper is familiar with the appear- 

 ance which suggests that it had not been entirely completed (fig. 11; 

 PL II, b). 



The long axis of the cell is nearly horizontal, the bottom of the cell 

 being normally only slightly lower than the mouth. The long axis 

 measures approximately one-half inch, while the perpendicular dis- 

 tance between any two diametrically opposite side walls is approx- 

 imately one-fifth of an inch. The side walls are each approximately 

 one-tenth of an inch wide. It is in such a cell, then, that the brood 

 of the age at which it cHes of sacbrood is found. 



Fig. 2.— Empty worker cell cut in half along 

 the long axis of the cell, showing cocoons (C) 

 at the base and near the mouth of the cell, 

 and the lowermost angle (A 2 ) formed by the 

 two walls which constitute the floor (F) of 

 the cell. Enlarged about 8 diameters. 

 (Original.) 



