CRITICAL INTENSITY AND FLASH DURATION FOR RESPONSE TO FLICKER: WITH ANAX LARVAE.

Determinations of the flicker response curve (F - log I(m)) with larvae of Anax junius (dragonfly) for various ratios t(L)/t(D) of light time to dark time in a flash cycle provide relations between t(L)/t(D) and the parameters of the probability integral fundamentally describing the F - log I function, including the variability of I. These relations are quantitatively of the same form as those found for this function in the sunfish, and are therefore non-specific. Their meaning for the theory of reaction to visual flicker is discussed. The asymmetry of the Anax curve, resulting from mechanical conditions affecting the reception of light by the arthropod eye, is (as predicted) reduced by relative lengthening of the fractional light time in a cycle.