452 



WILLIAM G. VAN DER KLOOT 



SUBESOPHAGEAL 

 GANGLION 



PROTOCEREBRUM 

 OF THE BRAIN 



'"'/TV 



CORPORA ALLATA 



c.a. hormone 



OVARY 



(promotes yolk deposition) 



DEVELOPING EGGS: 



Fig. 3. A diagrammatic summary of the control of egg development in the 

 roach, Leucophaea (Engehnann, 1957). For explanation see text. 



> excitatory nerve; > inhibitory nerve; 



^> excitatory hormone. 



becomes self-sustaining. Each time the young are born, the mechanical 

 stimulation is equivalent to mating, so the corpora allata are released from 

 inhibition and the next batch of eggs begins to mature. 



BRAIN 



CORPORA ALLATA 



c.a. hormone 



OVARY 



(promotes yoll< deposition) 



GENITAL APPARATUS i 



(stimuli from moling and parturition) 



Fig. 4. A diagrammatic summary of the control of egg development in the 

 roach, Diploptera (Engelmann, 1959). For explanation see text. 



> inhibitory nerve; > excitatory hormone. 



