1920] Hickernell: Digestive System of Cicada 233 



traction of the sphincter would so close the lumen as to prevent 

 effectively passage of any liquid. 



The Anterior Crop. 



The esophagus empties into the anterior crop through the 

 narrow opening described above. The walls of this division are 

 not uniformly differentiated (Fig. 9). The floor of the organ is 

 so constructed as to permit little expansion. The roof is much 

 folded, the folds apparently allowing some distension as a result 

 of the pressure of the contained liquid food. These differences 

 of structure are easily observed in either longitudinal or 

 transverse sections. 



The epithelium covering the floor of the anterior crop is 

 made up of columnar cells varying somewhat in length. Ante- 

 riorly its surface is thrown into a series of gentle folds (Fig. 8). 

 The folds increase in height until in the extreme posterior end 

 they much resemble the gastric crypts of some of the verte- 

 brates. The cell boundaries, easily seen in the distal portions of 

 the cells, become less sharply marked as the base of each cell 

 is approached. The cytoplasm of the cells is uniformly gran- 

 ular or homogeneous. No vacuoles or secretion products were 

 observed. The nuclei are large and chromatic and they may 

 be found in almost any position between the base and free ends 

 of the cells. No cuticula or striated border was observed, the 

 free ends of the cells having membranes similar to those cov- 

 ering the basal portions. 



"The roof of this division has an epithelium much different in 

 character from that above described. The cells are more cubical 

 than columnar. The dorsal folds are very deep (Fig. 9) while 

 secondary folds branch off from the one or two large primary 

 ones in such a fashion that in transverse section the pattern 

 formed resembles the branches of a tree. There is a pronounced 

 cuticula developed upon the surface of the dorsal epithelium. 



Cross sections through any part of the anterior crop region 

 show the ascending intestine and malpighian vessels to be closely 

 apposed to the dorsal wall of this organ. These tubes lie in the 

 depressions between the folds previously described but do not 

 actually penetrate the folds at any point. 



The entire mass formed by anterior crop and entwined tubes 

 is covered with a peritoneal membrane together with some 

 muscle fibres. The resulting saccular appearance and the 



