PLATE 6 



EXPLANATION OF FIGURES 



27 Third stage in the development of the adult photogenic organ of Photinus 

 consanguineus ; cross section. A, photogenic fat-spheres; C, cuticula; H, hypo- 

 dermis; it/, muscle; P, luminous layer; T, trachea; U, urate layer. 



28 Fourth stage in the development of the adult photogenic organ of Pho- 

 tinus consanguineus; cross section. A, fat tissue; C, cuticula; E, thickened 

 tracheal epithelium of photogenic layer, where the end-cells are formed ; /•'/>', 

 fat haemocytes; //, hypodermis; P, luminous layer ; T, tracheal epithelium; U, 

 urate layer. 



29 Fully developed adult photogenic organ of Photinus consanguineus, in 

 adult insect;' cross section. (', cuticula. c, capillaries of tracheal end-cells: //, 

 hypodermis; P, luminous layer; T, trachea; U, urate layer. 



30 Disintegrating photogenic organ of adult Kllvchnia corrusca. A, fat- 

 sphere; C, cuticula; //, hypodermis; .1/, muscle; P, luminous layer; T, trachea; 

 U, urate layer. 



19S 



