16 CIRCULAR 3 92, U. S. DEPARTMENT OF AGRICULTURE 



infection and the length of time the disease has been active. Dead 

 brood in open cells is removed by the bees sooner than that in sealed 

 cells. Occasionally the bees increase the thickness of the cappings 

 over dead brood in sealed cells. Such cappings appear dark, sunken, 

 and greasy, and are sharply depressed in the center. Dead larvae 

 may remain in these cells for months, or even over winter. 



APPEARANCE OF SICK BROOD AND TIME OF DEATH 



Sick larvae change from glistening white to dull or flat white, and 

 a slight loss of plumpness may be noticed. They move uneasily in 

 their cells and are often found in abnormal positions. A yellow 

 discoloration occasionally appears before the larvae die. 



Death from parafoulbrood usually occurs when the larvae are 

 coiled or irregularly twisted in the cells, but many extended larvae 

 and a few pupae are killed. The average age at the time of death 

 is usually somewhat greater than in case of European foulbrood. 



APPEARANCE OF DEAD BEOOD 



Larvae dead of parafoulbrood are coiled, irregularly twisted, or 

 fully extended in the cells, depending largely on the age when death 

 occurs. Usually the number of larvae and pupae that die in sealed 

 cells is somewhat greater and the number of larvae that die while 

 coiled is smaller than is the case in European foulbrood. 



Larvae that die in open cells dry rapidly and usually form light- 

 colored scales, although some become light brown, reddish brown, or 

 dark brown. Larvae that die in sealed cells dry more slowly, and 

 decay continues for a longer time. Many of these become reddish 

 brown during decay and form dark-colored scales. In an occasional 

 decayed larva or scale the tracheae show clearly. In sick or recently 

 dead larvae the stomach can be seen through the skin along the back. 

 The content of the stomach consists of a turbid grayish or yellow- 

 gray fluid that contains many bacteria. 



CONSISTENCY OF DEAD BEOOD 



Dead larvae soon become soft and watery. In capped cells some 

 become decidedly ropy during decay and form dark reddish-brown 

 or brown scales of a leathery consistency. In open cells the larvae 

 usually become pasty and later form light-colored brittle scales. In 

 some dead larvae ropiness develops rapidly, while in others it 

 develops slowly or is entirely absent. Ropiness in parafoulbrood 

 often resembles this symptom in American foulbrood. When this 

 occurs, a distinction can usually be made b} 7 noting the color and 

 odor of the dead brood. 



The scales can be removed easily from the cells. 



ODOE OF DEAD BEOOD 



Only a slight odor can be detected in recently dead brood, and 

 most larvae have but slight odor during decay. Many dead larvae 

 in sealed cells and also some in open cells, however, develop an 

 intense putrid odor similar to that of European foulbrood but fre- 

 quently much more intense. It can sometimes be detected as soon 



