m 



PLATE III. Electron-micrograph of the 

 tip of a tarsal contact chemo- 

 receptor of Stomoxys calcitrans 

 (X 20,000). (Courtesy of J. R. 

 Adams.) 



PLATE IV. Photomicrographs of images of newsprint formed by the corneal 

 lens of ocelli of the caterpillar Isia Isabella, ex is seen through a unitary 

 type cornea; x, through a tripartite type. (From Dethier, 1942.) 



