Sensory input to insect POL-neurons

Fig. 1:

Distribution and orientation of ommatidia in the dorsal rim area of the compound eye of the cricket, Gryllus campestris, as determined in a tangential section through the retina. Each of the small Ts stands for an ommatidium, the structure of which is given at the lower right. The orientation of the microvilli indicates the e-vector of maximal sensitivity for a receptor cell.