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THE PHYSIOLOGY OF INSECT SENSES 



Fig. 85. Simplified diagram of the neural pathways within the optic lobe of 

 Calliphora. R, retina; I, lamina ganglionaris ; II, medulla externa; 

 III, medulla interna; OC, outer chiasma; IC, inner chiasma. (Redrawn 

 from Cajal and Sanchez, 1915.) 



After the axons of the retinal cells traverse the basement membrane 

 about one from each ommatidium passes directly to the lamina, 

 while its five or six companions turn immediately at right angles, 

 forming local chiasmata with those of other ommatidia. The axons 

 then enter the lamina in groups or bundles, each bundle consisting of 



