PROC. ENT. SOC. WASH., VOL. 20, NO. 7, OCT., 1918 



153 



alimentary tract. Having reached the stomach it grows, invades 

 the epithelium and then multiplies -rapidly and to an enormous 

 extent. Never, however, has the germ been found be3 r ond the 

 basement membrane. 



Outside the basement membrane (fig. 1, bm) is the muscular 

 coat (m) comprised of three layers the external of longitudinal, 

 the middle of circular, and the inner of longitudinal fibers. Each 

 muscular layer consists of a single layer of branched fibers. 

 These fibers are separated from each other and therefore do not 

 form a compact layer. The branching fibers form a network of 

 anastomoses within each layer. Communications by branches 

 exist between the outer and middle layers and between the in- 



ep._< 



Fig. 1. A longitudinal section of the ventriculus of the adult honey bee 

 illustrating the three layers of the muscular coat (in). The spores of 

 Nosema apis are shown in the epithelium. 



ner and middle ones. Whether any such direct communication 

 exists between the outer and inner layers has not been estab- 

 lished. The diameter of the fibers of the outer and middle layer 

 are about equal and their number per unit of area is approxi- 

 mately the same. The diameter' of the fibers of the inner layer 

 on the other hand is much less than of the other two while the 

 number of fibers is much greater. The middle and inner layers 

 follow the course and extent of the basement membrane while the 

 fibers of the outer one bridge across the circular constrictions of 

 the organ. Apparently the fibers of all three muscular layers 

 are striated. While many of the preparations have not shown 

 this character it is yet to be demonstrated whether the absence 

 -of si nations are not due to the techniqu of fixation or staining. 



