12 



BULLETIN 431, U. S. DEPARTMENT OF AGRICULTURE. 



Fig. 8. — End view of capped cell which con- 

 tains a larva dead of sacbrood, being simi- 

 lar to the one shown in figure 9. The cap 

 here is not different from a cap of the same 

 age over a healthy larva. (Original.) 



stage is reached. It is rare to find a pupa dead of sacbrood (PL II, 

 zz). The larvae that die (fig. 7) are found lying extended lengthwise 

 with the dorsal side on the floor of the cell. They may be found in 



capped (fig. 8) cells or inxells which 

 have been uncapped i^g. 9), as bees 

 often remove the caps from cells 

 containing dead larvae. Caps that 

 are not removed are more often en- 

 tire, yet not infrequently they are 

 found to have been punctured by 

 the bees. Usually only one puncture 

 is found in a cap (PL II, d), but 

 there may be two (fig. 10) or even 

 more (PL 11,/) . The punctures vary 

 in size, sometimes approximating 

 that of a pinhead, although usually 

 smaller, and are often irregular in 

 outline. Sometimes a cap (fig. 11, 

 PL II, b) has a hole through it which 

 suggests by its position and uniform 

 circumference that it has never been 

 completed. Through such an opening (fig. 11; PL II, e) or through 

 one of the larger punctures the dead larva may be seen within the cell. 

 A larva recently dead of sacbrood is slightly yellow. The color in a 

 few days changes to brown. The shade 

 deepens as the process of decay con- 

 tinues, until it appears in some in- 

 stances almost black. Occasionally for 

 a time during the process of decay 

 the remains present a grayish appear- 

 ance. 



In sacbrood, during the process of 

 decay, the body wall of the dead larva 

 (figs. 7 and 9) toughens, permit- 

 ting the easy removal of the re- 

 mains intact from the cell. The 

 content of the saclike remains, dur- 

 ing a certain period- of its decay, is 

 watery and granular in appearance. 

 Much of the time the form of the 

 remains is quite similar to that of a 

 healthy larva. If the dead larva is not removed, its surface 

 through evaporation of its watery content, becomes wrinkled, dis- 

 torting its form. Further drying results in the formation of the 



Fig 



Looking into a cell containing a 

 larva dead of sacbrood. The stage of 

 decay is about the same as in figure 8. 

 (Original.) 



