EUROPEAN FOULBROOD. 3 



and the one that frequently has been associated in the literature Avith 

 Bacillus alvei. Ihis is unfoiiunate. While />. alrei is not the cause 

 of any bee disease, it occurs very frequently with European foul- 

 brood and is found only seldom in the rop}^ 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.^ 

 Death may take place ct any time from the fourth day of larval life to 

 l^upation. 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 

 larvse. 



GROUP 1 



The youngest larva (PI. II, D, G) that dies of European foulbrood 

 practically covers the bottom of the cell. It lies 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 tracheae can be seen with diffi- 

 culty, but by slight magnification they are readily observed. Most 

 of the tracheae, appearing as white lines, extend either dorsally or 

 ventrally on the lateral side of the larva, but a distinct chain con- 

 necting them wdll be observed to extend at right angles to these. 



GROUP 2 , 



Healthy larvae (PI. Ill, 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 tracheae are seen less easily than in younger larvae, 

 while the color, glistening appearance, prominence of segments, and 

 turgiclity are similar to those of the younger larvae described in 

 Group 1. 



By turning the larva so that its dorsal surface may be brought into 

 view (PL III, A) there is observed a more or less transparent narrow 



^ Tlie term larvae EkS used in the present paper applies to the prepupse as well as to 

 earlier stages of the brood. 



