e¹¹ flies have an abnormal electroretinogram; they show no transient responses at light-on or light-off. e¹¹ flies show defects when assayed in Buridan's paradigm; landmark fixation and walking appear to be close to the random level expected of blind flies or wild-type flies walking without landmarks. The walking distance of the e¹¹ flies exceeds that of wild-type flies in this assay.

Homozygous third instar larvae are unresponsive to UVC radiation.

A large fraction of homozygotes are arrhythmic with respect to locomotor activity when kept in constant darkness at 24^oC, and the average signal-to-noise ratio is lower than wild-type. Heterozygotes have intermediate SNR values between homozygotes and wild-type, indicating that their rhythmicity is not completely normal. At 20^oC, most homozygotes have weak rhythmicity or are arrhythmic, at 28^oC, most homozygotes have significant periodicity. Some homozygotes have extremely weak rhythms under a light-dark cycle. The eclosion rhythm is normal.

Body colour: dark. Tyrosinase formed in adults (Horowitz). Classifiable throughout larval period by dark spiracle sheaths (Brehme, 1941). Phenylthiocarbamide inhibits development of e¹¹ homozygotes more than wild type; reverse is true for inhibition by silver chloride; heterozygotes intermediate in both cases.Mixtures of the two inhibitors affect heterozygotes to a greater extent, thus exhibiting negative heterosis (Kroman and Parsons, 1960). Under ordinary conditions, viability and fecundity of heterozygote superior to either homozygote (Moree). RK1.