This ENU-induced mutation was isolated in a screen at the University of Pittsburgh. More than one mutation in this line results in a discernible phenotype in a homozygous recessive screen. At least two segregating phenotype groups are identified. See b2b1801.1Clo and b2b1801.2Clo Additional incidental mutations were detected in sequencing for the causative mutation, b2b1801Clo, and may be present in stocks carrying this mutation.