:'~-^ 



A'-v»k - „ >- j) . 



^jT- ^.^^.:t.v-;''V^ X^'rH^'*'-'''* ^ViijiM''*^ • '■ "~-*<«ysi^™ 



J^C 



Fig. 25. — Sectional view of photogenic organ of the firefly {after Williams), showing 

 reflector or crystal layer {U) above and photogenic cells (P) below. C, cuticula; T, trachea; 

 c, capillaries of tracheal end cells; H, hypodermis; EC, tracheal end cells; A'', nerve. 



