DIAGNOSING BEE DISEASES IN THE APIARY 



13 



would normally be spinning their coccoons (figs. 8, /-Z, and 10, 

 D-F). Comparatively few larvae die while fully extended (fig. 

 10, A, B, (7, G, H, I). Pupae are rarely affected by this disease. 



Figure 9. — European foulbrood ; heavily infected comb showing larvae in various stages 



of disease and decay. 



Larvae dead of European foulbrood, therefore, are usually coiled 

 on the bottom of the cells but may be irregularly twisted or fully 

 extended. 



COLOR OF THE DEAD BKOOD 



Soon after death larvae become dull and grayish or yellowish- 

 white. During decay the color deepens and may become brown or 

 almost black. The tracheae, or breathing tubes, in dead larvae usu- 

 ally show more clearly than in healthy ones (fig. 8, C and F). They 

 appear as radiating white lines in the dead coiled larvae and as 

 narrow white lines across larvae that die while extended. A white 

 line which crosses the radiating white lines can frequently be seen 

 on the side of dead larvae. The prominence of the tracheae is a 

 valuable symptom of European foulbrood but is not strictly depend- 

 able. 



An elongated, dull grayish- white or yellowish- white mass can be 

 seen through the skin along the back of sick and recently dead 

 larvae. This mass is within the chyle stomach and consists of a 

 turbid fluid that contains many bacteria. In healthy larvae, pollen 

 in the stomach can often be seen through the skin along the back 

 (fig. 8, J) , but the color is usually of a brighter and deeper shade 



