4 BULLETIN 780, U. S. DEPAKTMENT OF AGRICULTURE. 



taken up by Brotbeck (1857). Zander (1909) in his first paper re- 

 ferred to Nosema infection as a (malignant) dysentery. Other discus- 

 sions have appeared from time to time in regard to such relationship 

 (Maassen and Nithack, 1910; Beuhne, 1911; Maassen, 1911). 



In fact the two disorders are very different and should be con- 

 sidered, for the present at least, as having no direct relation to each 

 other. As both conditions are widely distributed and occur most 

 frequently in the spring of the year, it is to be expected that not 

 infrequently both of them may be encountered together in the same 

 colony. 



Efforts have been made to determine the name by which Nosema- 

 disease has been known to beekeepers in the past. In these studies 

 it was found (p. 16) that the highest percentage of Nosema-infected 

 bees occurred in weak colonies. Consequently in asking beekeepers 

 for samples bees from weak colonies were requested. In response 

 to the request made approximately 150 samples were received. 

 FuUy half of these contained Nosema apis. Nine representative 

 beekeepers located in different sections of the country that sent 

 Nosema-infected bees were asked concerning the name by which the 

 colonies showing the weakened condition were known. Three replied 

 spring dwindling; two, not spring dwindling; two, weak colonies; one, 

 bad queen; and one, "Don't know." None suggested paralysis and 

 none dysentery. 



In reply to requests for bees from colonies showing spring dwindling 

 38 samples were received from 14 beekeepers located in different 

 sections of the country. Out of the 38 samples 15 upon examination 

 revealed the presence of Nosema apis. From these 15 samples 314 

 bees were examined; of which 70 were found to be Nosema-infected. 



Samples have been received from five beekeepers who diagnosed 

 the condition in the colonies from which the bees were taken as 

 paralysis. Nosema apis was not found in any of them. 



The facts indicate, it would seem, that beekeepers had not learned 

 to recognize the disease produced by Nosema apis by any one name. 



DIGESTrSTE TRACT OF ADULT BEES. 



In Nosema infection the parasite Nosema apis enters, infects, and 

 leaves the bee by way of the digestive tract. It is well, therefore, to 

 know something of the location, arrangement, appearance, and 

 structure of the organs of the alimentary canal of the healthy adult 

 bee in order that the disease when encountered may be recognized 

 and more fuUy understood. 



The following description is an abbreviation of a general survey of 

 the alimentary tract by Snodgrass (1910). The part of the alimentary 

 canal (fig. 1) immediately following the mouth forms an enlargement 

 called the pharynx (PJiy). Succeeding this is the oesophagus (CE), 



