EXPLANATION OF PLATES 
PLATE I 
Brood-combs containing larve that are sick and others that are dead of Euro- 
pean foulbrood, showing the irregular appearance of the brood. About one-half 
natural size. 
A.—The dead larve have all been removed. Some of the remaining larve 
are sick, others are not infected. The disease was produced by experimental 
inoculation. 
B.—Many of the dead larve have not been removed. The comb had been 
out of the colony for a considerable period. The larvz that are quite young 
showing abnormal position and appearance are not sick or dead of European 
foulbrood, but are so as a result of the comb being away from the colony. 
Disease was produced by experimental inoculation. 
C.—The comb was taken from a colony in which the disease had appeared 
in nature and not as the result of artificial inoculation. Before being photo- 
graphed the brood-comb had been out of the hive for a few days. Aside from 
the larve which are dead of European foulbrood, other larve present are dead 
from lack of attention by adult bees—starvation, exposure, and other causes. 
PLATE II 
A.—Live larva showing first symptoms of European foulbrood. The tur- 
gidity is slightly less than in a healthy larva (D). 
B.—Live larva showing early symptoms of European foulbrood. The body 
is more transparent than that of a healthy larva (D). Small opaque areas give 
it a punctate appearance. 
C.—Larva dead of European foulbrood contained within a chitinous envelope 
filled with a watery-appearing fluid. 
D.—Healthy larva of the earliest age at which larve die of European foul- 
brood. Turgidity marked. 
E.—European foulbrood larva which may or may not be dead. Surface less 
glistening than in healthy larve. Marked turgidity lost. Prominence of tracheze 
not increased. 
F.—Scale formed by .drying of larve dead at early age. Prominence of 
trachez marked. 
G.—View of healthy larva in normal position with roof of cell removed. 
Larva turgid. Surface glistening. 
H.—Larva sick with European foulbrood. Lack of turgidity and increased 
prominence of trachez observed. 
I.—European foulbrood larva which may or may not be dead. Less turgidity, 
a relative dullness in the surface appearance, and punctate condition present. 
Similar to E. 
PLATE IIT 
A.—Healthy larva immediately preceding the age at which the capping of the 
cell is done. Dorsal surface turned toward the observer. The narrow trans- 
parent area along the dorsal median line is prominent. 
B.—Larva dead of European foulbrood of the same age as A. The turgidity, 
glistening surface, and transparent area are less marked. 
C.—Larva dead of Huropean foulbrood partly coiled and partly endwise in 
cell. 
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