EUROPEAN FOULBROOD. 3 
and the one that frequently has been associated in the literature with 
Bacillus alvei. This is unfortunate. While B. alvei is not the cause 
of any bee disease, it occurs very frequently with European foul- 
brood and is found only seldom in the ropy disease. In using the 
names European foulbrood and American foulbrood it is possible, 
however, to avoid confusion by bearing well in mind the history of 
the disease. 
HEALTHY LARV OF THE AGE AT WHICH THEY DIE OF 
EUROPEAN FOULBROOD 
Bees dying of European foulbrood do so during the larval stage.t 
Death may take place <t any time from the fourth day of larval life to 
pupation. For convenience of description the brood of the age at 
which death from European foulbrood occurs is placed here in three 
groups. Groups 1 and 2 include the uncapped and group 3 the capped 
larvee. 
GROUP 1 
The youngest larva (Pl. II, D, G) that dies of European foulbrood 
practically covers the bottom of the cell. It hes either on its right or 
its left side, with its dorsal portion extending to the lateral walls of 
the cell. Its form is C shaped with the anterior and posterior ex- 
tremities almost together. Its color is bluish white with a glistening 
surface, presenting a pearly appearance. The body is more or less 
opaque, due largely to the adipose tissue. Folds and furrows divide 
the surface into segments. In health these are quite prominent and 
the entire larva is turgid in appearance. 
With the unaided eye spiracles and trachew can be seen with diffi- 
culty, but by slight magnification they are readily observed. Most 
of the trachez, appearing as white lines, extend either dorsally or 
ventrally on the lateral side of the larva, but a distinct chain con- 
necting them will be observed to extend at right angles to these. 
GROUP 2 
Healthy larve (PIL. III, D, G) slightly older than those described in 
Group 1 constitute Group 2. The larva now completely fills the 
bottom of the cell. The dorsal side pressing against the lateral side 
walls of the cell causes the contour of the body to be in general 
hexagonal. The trachee are seen less easily than in younger larve, 
while the color, glistening appearance, prominence of segments, and 
turgidity are similar to those of the younger larve described in 
Group 1. 
By turning the larva so that its dorsal surface may be brought into 
view (PI. III, A) there is observed a more or less transparent narrow 
1The term larve as used in the present paper applies to the prepupe as well as to 
earlier stages of the brood. 
