132 JOURNAL OF ECONOMIC ENTOMOLOGY [Vpl. 14 



colonies is often difficult because of the fact, as is particularly the case 

 with European foulbrood, there are many irregularities and variations 

 in symptoms that often add to the confusion of the beekeeper in making 

 gross diagnosis hurriedly in the field. In order to more easily differen- 

 tiate some of these confusing s^Trnptoms to assist in gross diagnosis, they 

 may be divided into three classes. Occasionally in an unusually virulent 

 case of American foulbrood or in one where the bees have deserted the 

 brood because of its foul condition allowing what healthy brood there 

 is to starve, larvae will be found which have died while still coiled in the 

 cell, among the typical American foulbrood larvae.^ These coiled 

 larvae often have much the same appearance as typical European foul- 

 brood coiled larvae. However, the consistency is generally quite dif- 

 ferent from European foulbrood, more like the typical slimy glue-like 

 consistency of American foulbrood material. As a rule, however, the 

 symptoms of American foulbrood are uniformly constant because of the 

 fact that Bacillus larvae is almost always the only invader of the larvae 

 causing death and a type of decomposition which prevents growth of 

 other organisms. Several such cases were found in California. 



A second class of confusing sjanptoms are found in samples which 

 come particularly from regions where European foulbrood has been 

 allowed to run unchecked for a long time. Such samples were found 

 in certain sections of California and have been received from various 

 other sections of the country. These samples show along with more 

 or less of the typically coiled European foulbrood larvae, large numbers 

 of larvae which have died after extending and even being sealed in the 

 cell, showing a consistency somewhat like that of American foulbrood 

 but more lumpy or like an old partly rotten rubber band.^ Sometimes 

 scales are found extended in the cells in such large ntunbers as to appear 

 on casual examination Hke an old comb of American foulbrood. Close 

 examination, however, shows the consistency, irregular shape and posi- 

 tion with lack of adherence to the cell wall to be different from that in 

 American foulbrood. This type was found to be quite prevalent in 

 California. 



The third class is composed of cases of actual mixed infection where 

 typical American foulbrood, ropy larvae or scales, are associated in the 

 same comb with typical European foulbrood, coiled moist melting larvae, 

 or possibly occasionally the abnormal rubbery irregular larvae mentioned 

 above. The active stage of the two diseases often seems to be localized 

 more or less in different parts of the comb. This is probably due to 



*White, G. F. 1920. American foulbrood. U. S. Dept. of Agric. Bui. No. 809, 

 'Sturtevant, A. P., 1920. A study of the behavior of colonies affected by European 

 foulbrood of bees. U. S. Dept. of Agric. Bui. No. 804. 



