Bui. 780, U. S. Dept. of Agriculture. 



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Further Studies on Nosema apis as Revealed by the Microscope. 



G, Nosema apis as seen in a stained smear preparation; H, a stained smear preparation showing within 

 the groups how closely the cells are packed with parasites (note the nucleus of an epithelial cell below 

 and to the right of the center); /, smear showing young forms (note the paired appearance); J, por- 

 tions of epithelial cells are shed into the lumen of the stomach, carrying with them the contamed 

 parasites, accounting for the groups in this photograph; K, cross sections of Malpighian tubules 

 highly magnified (the epithelial cells of the one to the left are not infected, some of those of the 

 one above contain parasites, while all of those of the one to the right are heavily infected); L, tangen- 

 tial section of stomach wall showing the three muscular layers, the fiber of all of them being branched 

 and striated. The irmer and outer layers are made up of longitudinal fibers while the middle one 

 consists of circular ones. (Original.) 



