ITOSEMA-DISEASE. 



a slender tube traversing the entire thorax. In the anterior part of 

 the abdomen the oesophagus expands into a large thin-walled sac 

 which is known as the honey stomach (HS) ; next is the short neck- 

 like portion, the proventriculus (Pvent); then comes the large U- 

 shaped portion, the stomach or ventriculus (Vent), an organ with 

 thick walls and many annular constrictions. Following the stomach 

 is the short, narrow 

 and coiled, small in- 

 testine (SInt) having 

 a circle of about one 

 hundred long, greatly 

 coiled, blind, thread- 

 like tubes opening 

 into its anterior end. 

 These tubes are the 

 Malpighian tubules 

 {Mdl). Following the 

 small intestine is the 

 large intestine or rec- 

 tum {Eect). When 

 bees have been con- 

 fined for some time 

 this latter portion of 

 the canal is found dis- 

 tended with material 

 to be voided. 



Since the stomach is 

 always invaded by the 

 parasite in Nosema- 

 disease, and the Mal- 

 pighian tubules occa- 

 sionally are, a further 

 description of the 

 structure of these or- 

 gans seems warranted. 



The stomach (fig. 

 1, Vent) is a relatively 

 thick-walled organ 

 lying U-shaped within 

 the abdomen. When 

 removed and straight- 

 ened it is seen to be in general cyHndrical but somewhat spindle-shaped 

 in form. (PI. I.) Circular constrictions present give to it a segmented 

 appearance. The number and distinctness of these transverse mark- 

 ings vary somewhat. The size of the organ and its color vary also. 

 The color varies within wide limits, being usually some shade of 



\fent 



Fig. 1. — Alimentary canal of worker bee: Pharynx (Pftj/), oesophagus 

 • (ffi), honey stomach (HS), proventriculus {Pvent), stomach or 

 ventriculus {Vent), small intestine (S/ni), and large intestine or 

 rectum {Rect}, rectal glands {RGl), Malpighian tubules (J/aZ)_ 

 Salivary glands of head {2GI) and thorax {SGI), and pharyngeal 

 glands {IGl) are also shown. (Snodgrass.) 



