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. The rhythmicity is not affected by temperature. Homozygotes sometimes show abnormal synchronisation to light-dark cycles. The eclosion rhythm is normal.

Body colour: black.

Ability to incorporate beta-alanine-derived C intermediate between that of e¹ and wild type.

Classifiable from hatching throughout larval period by dark color of spiracle sheaths, although darkening is less than in e¹, e⁴, or e¹¹.

RK1. Body colour: darker than wild-type but lighter than e¹.