EXPERIMENT STATION BULLETINS. 529 



the observer so that a bright light strikes the lower side wall (fig. 3). 

 A very characteristic and usually penetrating odor is often noticeable 

 in the decaying larvae. This can perhaps best be likened to the odor of 

 heated glue." 



''The majority of the larvae which die of this disease are attacked 

 after being sealed in the cells. The cappings are often entirely removed 

 by the bees, but when they are left they usually become sunken (fig. 1, 

 g, c, j) and frequently perforated (fig. 1, c, j). As the healthy brood 

 emerges the comb shows the scattered sunken cappings covering dead 

 larvae (fig. 3), giving it a characteristic appearance." 



"Pupae also may die of this disease, in which case they, too, dry 

 down (fig. 1, o, d), become ropy, and have the characteristic odor and 

 color. The tongue frequently adheres to the upper side wall and often 

 remains there even after the pupa has dried down to a scale. Younger 

 unsealed larvae are sometimes afi'ected. Usually the disease attacks 

 only worker brood, but occasional cases are found in which queen and 

 drone brood are diseased. It is not certain that race of bees, season, or 

 climate have any effect on the virulence of this disease, except that 

 in warmer climates, where the breeding season is prolonged, the rapid- 

 ity of devastation is more marked." 



EUROPEAN FOUL BROOD. 



"European foul brood was formerly called 'black brood' or 'New 

 York bee disease.' The name 'black brood' was a poor one, for the 

 color of the dead brood is rarely black or even very dark brown. 

 European foul brood usually attacks the larva at an earlier stage of its 

 development than American foul brood and while it is still curled up at 

 the base of the cell (fig. 4, r). A small percentage of larvae dies after 

 capping, but sometimes quite young larvae are attached (fig. 4, e, m). 

 Sunken and perforated cappings are sometimes observed just as in 

 American foul brood (fig. 1, c, g, j). The earliest indication of the 

 disease is a slight yellow or gray discoloration and uneasy movement of 

 the larva in the cell. The larva loses its well-rounded, opaque appear- 

 ance and becomes slightly translucent, so that the tracheae may become 

 prominent (fig. 4, b), giving the larvae a clearly segmented appearance. 

 The larva is usually flattened against the base of the cell, but may turn 

 so that the ends of the larva are to the rear of the cell (fig. 4, p), or 

 may fall away from the base (fig. 4, e, g, 1). Later the color changes to 

 a decided yellow or gray and the translucency is lost (fig. 4, q. h). The 

 yellow color may be taken as the chief characteristic of this disease. 

 The dead larva appears as a moist, somewhat collapsed mass, giving the 

 appearance of being melted. When the remains have become almost dry 

 (fig. 4, c) the tracheae sometimes become conspicuous again, this time 

 by retaining their shape, while the rest of the body content dries around 

 them. Finally all that is left of the larva is a grayish-brown scale 

 against the base of the cell (fig. 4, f, h), or a shapeless mass on the 

 lower side wall if the larva did not retain its normal position (fig. 4, 

 n, o). Very few scales are black. The scales are not adhesive, but are 

 easily removed, and the bees carry out a great many in their efforts to 

 clean house." 



"Decaying larvae which have died of this disease are usually not ropy 

 as in American foul brood, but a slight ropiness is sometimes observed. 

 67 



