EUROPEAN FOULBROOI). 5 



beekeepers, a condition noticeable wlien tlie disease is fairly well 

 advanced in the colony. 



The dead larva' lose their jiearly whiteness and assume a yellowish 

 color, later becoming brownish. This deepens often to a dark brown. 

 The decaying remains are not characteristically ropy, as in American 

 foulbrood. Marked viscidity is usually absent. When it is present 

 the decaying mass can be drawn into threads but to a less extent than 

 in the ropy disease. In advanced cases the disease may be accom- 

 panied by an odor, but in the writer's experience this never has been 

 marked and never offensive. 



As the disease in the colony advances, weakness becomes a symp- 

 tom. In severe cases queenlessness may result from the infection. 

 This, however, is by no means the rule. 



SYMPTOMS MANIFESTED BY INDIVIDUAL LARV^ SICK OR DEAD OF EUROPEAN 



FOULBROOD 



Evidences of European foulbrood in the individual larvae appear 

 before and after death. The colony symptoms used most frequently 

 in the diagnosis of the disease are largely post-mortem aj)pearances 

 of larvae. Of much interest and frequently of considerable diagnos- 

 tic value are the symptoms manifest by larvae sick but not dead of 

 the disease. For convenience in the description of the appearances 

 of the sick or dead larvae, the grouping used in describing the 

 healthy larvae (p. 3) is followed. The appearances of affected 

 larvae both living and dead are, of course, changing constantly. A 

 description which is correct for one day or hour, it should be 

 realized, is not likely to be entirely correct for the next. 



GBOtJP 1 



The youngest larvae manifesting symptoms of European foul- 

 brood are approximately 4 days old (PI. II, A, B, C, E, F, H, I). In 

 many cases at this stage of the disease a peristalsis-like movement of 

 the body is marked and is readily observed by the unaided eye, but 

 in others no such bodily movements are observed. The diseased 

 larvae at the time may be more transparent (PL II, B, H) than 

 healthy ones of the same size. In such larvae the tracheae are quite 

 prominent and more readily seen than in healthy ones. Occasionally 

 numerous minute opaque areas are observed in these more transpar- 

 ent larvae, giving to them a punctate appearance. Very often, how- 

 ever, this sign is not present. In many instances, indeed, no distinct 

 symptom is observed until the larva approaches death. (PI. II, A). 



Larvae (PI. II, A, B, C, E, H, I) of this group dying or just dead 

 of the disease lose their marked glistening appearance; their pearly 

 whiteness gives way to a yellowish tint ; the turgidity seen in healthy 

 larvae is diminished in the sick; and the folds and furrows indicat- 



