30 TECHNICAI. BULLETIN 149, IT. S. DEPT. OF AGEICULTUEE 

 Table 5. — DaUy death rate of bees in cages when given honey for food — Contd. 



^ Records of the number of deaths were not made on these days. 



The graphs of Figures 1 to 4 and Tables 1 to 4 show the rate of 

 mortality obtained under varying conditions when fungous extracts 

 mixed with dilute honey were fed to bees in cages. 



The normal death rate for caged bees when given honey as food 

 is shown in Table 6 and in the graphs of Figure 5. Graphs 1 and 2 

 of this figure were drawn from data obtained by Phillips (19, p. 

 396-399) on the death rate of bees in cages when given honey for 



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FiGUEE 5. — Rate of mortality of lots of honeytiees in cages when fed with honey. This 

 graph represents normal death rates for bees kept in cages 



food. Graphs 3 and 4 were drawn from data obtained by the writer 

 while determining the normal death rate of bees in cages, as checks 

 upon other experiments. These cages were kept in the laboratory on 

 the opposite side of the room from the source of light. The bees 

 were supplied with honey diluted with an equal volume of water. 

 The temperature of the laboratory during the time that the experi- 

 ments were in progress ranged between 23° and 27° C. 



In view of the difference in death rate between the experiments of 

 Phillips and those of the writer, when bees in cages were given honey 

 for food, one is led to believe that there were important differences 

 m the conditions of the experiments. Either the bees used by Phil- 

 lips were not entirely healthy or the conditions under which 

 his experiments were conducted were less favorable for caged bees. 



RESULTS OF EXPERIMENTS WITH THE PENICILLIA 



Wliile studying the fungi associated with honeybees the writer 

 {5,f. 64) found that species of Penicillium caused the mummification 

 of b.ees more often than did any of the other forms. Bees mummi- 

 fied by Penicillia resemble closely those killed by Aspergilli. At- 

 tempts weremade to infect healthy bees with cultures of Penicillium 

 isolated from other bees. Adult bees in cages and in colonies were 

 unaffected when spores of these organisms were fed to them. Adult 

 bees and brood in colonies exposed to the cultures of Penicillium on 



