154 



THE COCKROACH I 



supporting plate of the spiracle, and is inserted opposite to the 

 occlusor, into the extremity of the bow. 



A 



C 



Fig. 37, Four views of the First Abdominal Spiracle (left side). X 70. The bow 



is shaded in all the figures. (P. americana.) 



A The spiracle, seen from the outside ; p, lateral pouch ; /, internal aperture. 



B Do., side view. 



C Do., seen from the inside, the aperture open. The occlusor muscle 



is shown. 

 D The spiracle, seen from the inside, the aperture shut. 



