THE CANADIAN ENTOMOLOGIST 279 



thickness from three to ten micra. Dietrich's, Bouins', and Flem- 

 ing's (strong formula) Fluids were used for fixation. Best results 

 were obtained with the last fluid, although Dietrich's Fluid gave 

 excellent results. Sections were stained with Heidenhain's Iron 

 Haematoxylin and Delafield's Haematoxylin with Eosin used as a 

 counterstain. Better results were obtained with the former stain, 

 especially after fixation with the Fleming's Fluid. 



Cross and longitudinal sections through the region of the 

 pores, showed that the hypodermis was very much thickened, and 

 apparently consisted of several layers of cells (Figs. 4 and 5). 

 The upper layer consisted of hypodermal cells with elongate, 

 flattened, deeply stained nuclei, with axes parallel to the surface 

 of the cuticula, and surrounded by but little cytoplasm. They 

 resemble the normal hypodermal cells found in other regions of 

 the body, but are not so regularly arranged nor contiguous, being 

 scattered here and there between the upper ends of the cells of the 

 lower layers. 



Below these smaller cells, larger cells were present, sometimes 

 appearing as a single layer, at other times presenting the ap- 

 pearance of two or more layers, due to the fact that they were 

 crowded together so that their nuclei had been somewhat dis- 

 placed. Longitudinal sections showed that these lower cells 

 were not perpendicular to the surface of the cuticula, but slanted 

 backwards at a considerable angle. They are somewhat columnar 

 in shape, but vary much in this respect due to their being crowded 

 together. 



The minute structure of these cells is represented by figures 

 6 and 7. They possess large vesicular nuclei with distinct nuclear 

 walls, prominent nucleoli, and deeply-stained chromatin granules. 

 The cytoplasm of the individual cells is distinctly areolar in ap- 

 pearance. The most striking feature about these cells though is 

 the presence in the cytoplasm of a rounded reservoir from which 

 extends a delicate chitinous canal which opens at the surface 

 by one of the pores previously described. The reservoir may be 

 either laterad or somewhat beneath the nucleus, and the canal 

 in many cases is quite sinuous, so that in sections, only portions 

 of it show here and there. Surrounding the reservoir the cytoplasm 



