PLATE IV. —To Illustrate the Anatomy of the Digestive System op 



THE Imago. 



A. Outline figure of a female Cidex, to show the relations of the intestinal 



canal and its appendages, x 15 diams. 



B. The rectal glands lying in situ cu the large intestine, with their tracheal 



supply. X 75 diams. 



C. Isolated cells of rectal glands, x 300 diams. 



D. Chitinous pharyngeal bulb, x 75 diams. 



E. Blind extremity of a Malphigian tube, x about 200 diams. 



F. Semi-diagrammatic representation of the parts about the mouth, x about 



75 diams. 



O. The salivary glands and their ducts lying in situ on the pharynx and 

 oesophagus, x 75 diams. 



H. Salivary duct of one side and its branches, the middle one of which, 

 though mainly denuded, has attached to it two clusters of salivary 

 cells. X 430 diams. 



K. Normal salivary cells somewhat more highly magnified. 



In the above figures : a, labrum ; b, mandible ; c, labium ; d, buccal bulb ; 

 e, oesophagus ; /, salivary duct ; g, nerve ; k, " hypopharynx " ; m, 

 Malphigian tubes ; n, chitinous pharyngeal bulb ; o, spiral valve of 

 large intestine ; p, pneumatic vesicle (dotted outline of) ; q, trachea 

 supplying the cellular tissue of the labium ; r, rectum ; s, salivary 

 glands ; t, rectal glands ; v, stomach. 

 The chitinous framework of the head is indicated by coarse oblique 



shading ; the outline of labrum in dotted, and that of the labium in broken 



dotted lines. 



