EXPLANATION OF PLATES 



PLATE I 



Brood affected with American foulbrood: 



A. — American foulbrood produced by the feeding of pure cultures of Bacillus larvae, showing the later 

 stages of decay of the brood. 



B.— American foulbrood produced experimentally, showing irregular distribution of capped and un- 

 capped cells, punctured caps, and scales. 



C. — American foulbrood, showing sunken and punctured caps. The sample was shipped by mail for 

 diagnosis. 



PLATE II 



Healthy bee larvae (prepup&e) and first and second postmortem stages of American foulbrood larvae as 

 described in the present paper: 



A. — Cap of cell containing a healthy larva. Being recently constructed, it is convex. 



B.— Cap of cell containing a larva recently dead of the disease. It is not unlike many of the caps over 

 healthy larvae. 



C— Cap of cell containing a diseased larva. It is slightly sunken. 



D .—End view of a healthy larva. The cap was removed artificially. (In the laboratory this is done con- 

 veniently with fine pointed curved forceps or a dissecting needle.) 



E.— End view of larva illustrating the earliest (first) stage of American foulbrood. 



F.— End view of larva which has reached the second stage. 



G .—Ventral view of a healthy larva of the age at which death from American foulbrood frequently occurs. 



H.— Ventral view of larva illustrating the first stage after death. 



I.— Ventral view of larva showing second stage. 



PLATE III 



Third, fourth, and fifth stages of decay in American foulbrood larvae: 



A.— Punctured cap of cell containing a dead larva. 



B.— End view of larva illustrating the fourth stage of decay. The cap was removed artificially as indi- 

 cated by the torn edges. 



C— End view of larva illustrating the fifth stage of decay, the scale. The cap had been removed by the 

 bees, as shown by the smooth condition of the mouth of the cell. 



D .—End view of larva, third stage. 



E.— End view of larva, fourth stage. 



F.— End view of larva, fifth stage— the scale. 



G.— Ventral view of larva, third stage. 



H.— Ventral view of larva, fourth stage. 



I.— Ventral view of larva, fifth stage— the scale. 



PLATE IV 



Healthy pupae and first and second postmortem stages of American foulbrood pupae as described in tho 

 present paper: 



A. — Healthy pupa of the age at which death from American foulbrood occurs. 



B. — End view of pupa, first stage of the disease. 



C— End view of pupa, second stage. 



D. — Ventral view of pupa of the age at which death from American foulbrood occurs. 



E.— Ventral view of pupa, first stage. 

 * F.— Ventral view of pupa, second stage. 



PLATE V 



Third, fourth, and fifth postmortem stages of American foulbrood as described in the present paper: 



A.— End view of pupa, third stage. 



B.— End view of pupa, fourth stage. 



C— End view of pupa, fifth stage— the scale. 



D.— Ventral view of pupa, third stage. 



E.— Ventral view of pupa, fourth stage. 



F.— Ventral view of pupa, fifth stage— the scale. 



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