. Sacbrood. Bees. SACBROOD. 13 "scale" (figs. 22\ 23; PI. II, I, r, and x). This scale is not adherent to the cell waU. In sacbrood the brood combs may be said to have no odor. Larvae imdergoing later stages of decay in the disease, however, when crushed in a mass and held close to the nostrils are found to possess a disagreeable odor. From a superficial or casual ex- amination alone of a case of sac- brood it may be mistaken for some other abnormal condition of the brood. A careful study of the post- mortem appearances of larvse dead of the disease, however, will make it possible to
. Sacbrood. Bees. SACBROOD. 13 "scale" (figs. 22\ 23; PI. II, I, r, and x). This scale is not adherent to the cell waU. In sacbrood the brood combs may be said to have no odor. Larvae imdergoing later stages of decay in the disease, however, when crushed in a mass and held close to the nostrils are found to possess a disagreeable odor. From a superficial or casual ex- amination alone of a case of sac- brood it may be mistaken for some other abnormal condition of the brood. A careful study of the post- mortem appearances of larvse dead of the disease, however, will make it possible to avoid any such confusion. A more careful study of the dead larvse is therefore Fio. 10.—Cap of cell containing the remains of a larva dead of sacbrood. The cap is slightly sunken and bears two perforations made by the bees. (Original.) APPEARANCE OF LARV.«! DEAD OF SACBROOD. No signs in a larva dying of sac- brood have yet been discovered by which the exact time of death may be determined. As the larvse in this disease usually die diu-ing the time when' they are motionless, lack of movement can not be used as an early sign of death. In this descrip- tion it is assumed that the larva is dead if it shows a change in color from bluish-white to yellowish or indications of a change from the normal turgidity to a condition of flaccidity. The appearance of a larva dead of sacbrood varies from day to day, changing gradually from that of a living healthy larva to that of the dried residue—the scale. A de- scription that would be correct for a dead larva on one day, there- fore, may and probably would be incorrect for the same larva on the following day. Moreover, all larvse dead of the disease do not imdergo the same change in appear- ance, causing another considerable range of variation. For con- venience of description, this gradual and continual change in appear- ance is here considered in five more or less arbitrary stages. As the. Please note that these images are
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisherwa, booksubjectbees
