PLATE 5 



EXPLANATION OP FIGURES 



22 Tracheal capillary penetrating the larval photogenic organ of Photinus 

 consanguineus. c, capillary; T, trachea. 



23 Tracheal end-cell penetrating the photogenic layer of the adult Photinus 

 consanguineus; partly from Lund, c, capillary; EC, end-cell; T, trachea. 



24 Earliest stage observed in the formation of the adult photogenic organ 

 of Photinus consanguineus; sagittal section. ^4, photogenic fat sphere, C, cutic- 

 ula; FB, fat haemocytes; H, hypodermis; /, investment; P, photogenic cells issu- 

 ing from fat-sphere; SB, segmental blood cells; T, trachea. 



25 Second stage in the development of the adult photogenic organ of Phot inns 

 consanguineus, lettering as in figure 24; cross section; here a number of the 

 photogenic cells have migrated to the hypodermis. 



26 Cross section through the region of the photogenic organ of an early 

 pupa of Photinus consanguineus. at a later stage of development than figured in 

 25. A, fat-sphere; C, cuticula; D, dorsal vessel; H, hypodermis; /, intestine; 

 K, Malpighian Tubule; M, muscle; A r , nervous system; O, oenocyte; P, forming 

 photogenic organ; T, trachea; V, vas deferens. 



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