SACBROOD. 



21 



plainly visible. The margin frequently presents a wavy outline cor- 

 responding to the original furrows and ridges of the lateral margin of 

 the larva. 



Posterior third. — The posterior third (figs. 23 and 24) extends upon 

 the bottom of the cell, but does not completely cover it. A lateral 

 view of the scale (fig. 24) shows that it is turned upward anteriorly 

 and drawn somewhat toward the bottom of the cell. The ventral 

 surface is concave, often roughened, and directed somewhat forward. 

 This margin, like that of the middle third, has a tendency toward 

 being irregular. 



The scale. — The scale can easily be removed intact from the cell. 

 (PL II, x.) Indeed, when very dry, many of them can be shaken 

 from the brood comb. When out of the cell, they vary markedly 

 in appearance. The anterior third is of a deeper brown than the 

 the other two thirds as a rule. The dorsal side of the middle and 



JP^W 



Fig. 24.— Scale, or larval remains, in position in cell cut lengthwise, lateral view. (Original.) 



posterior thirds is shaped to conform to the floor of the cell, being in 

 general convex, with a surface that is smooth and polished. The 

 margin is thin and wavy. The anterior third and the lateral sides of 

 the middle and posterior thirds being turned upward, the ventral sur- 

 face being concave, and the posterior side being convex, the scale in 

 general presents a boatlike appearance and could be styled " gondola- 

 shaped." This general form of the scale has been referred to by 

 beekeepers as being that of a Chinaman's shoe. When completely 

 dry, the scale is brittle and may easily be ground to a powder. 



Condition of the virus in the scale. — The scales in sacbrood, when fed 

 to healthy bees, have shown no evidence of being infectious. 



The length of time that dead larvae are permitted by the bees 

 to remain in the cells before they are removed varies. They may be 

 removed soon after death, they may remain until or after they have 

 become a dry scale, or they may be removed at any intervening stage 

 in their decay. Not infrequently they are permitted to remain to or 



