280 THE CANADIAN ENTOMOLOGIST 



is much more granular, the granules evidently being the secretion 

 which collects in that region, and empties into the reservoir. 

 From here the secretion is carried to the exterior through the 

 minute canals, where it collects in the depressions in the cuticula. 



What the nature of this secretion is, the writer did not de- 

 termine. From the structure of the glands, and their resemblance 

 to odoriferous glands of other insects, the writer is inclined to 

 believe they perform a similar function in the case of the 

 cockroach. 



The writer wishes to express his thanks to Dr. W. A. Riley 

 for his suggestions and advice in this work. 



Explanation of Plate VI. 



Fig. 1. Dorsal aspect of the 10 abdominal segment of the 9 

 cockroach, showing location of the depressions in 

 the cuticula. D, depressions; C, cerci. 



Fig. 2. Appearance of depressions under oil immersion lens. P. 

 pore. 



Fig. 3. Cross-section through a depression. Cu, cuticula; P, 

 pore. 



Fig. 4. Longitudinal section through the region of the pores. 

 Cu, cuticula; Hyp., hypodermis; Gl., glands. 



Fig. 5. Cross-section through the middle group of depressions. 

 D., depression; N. Hyp., normal hypodermis; Gl., 

 glands. 



Fig. 6. Longitudinal section through the region of the pores 

 (greatly enlarged). D., depression; Cu., cuticula; N. 

 Hyp., normal hypodermis; Gl., glands. 



Fig. 7. Glandular cell (greatly enlarged). Cu., cuticula; P., 

 pore; C, canal;' R., reservoir; B.M., basement 

 membrane. 



