Heterozygotes exhibit curly upturned wings, crossed posterior scutellars and darker than normal body colour. Transheterozygotes with U1 exhibit the same phenotype.
Viable over U1. Lethal over an X-ray induced revertant of U1. Upturned wings, crossed posterior scutellars, and darker than normal body color are observed in U2 heterozygotes and U1/U2 heteroalleles. Wing phenotype is additive with that of Cy1.