Thoracic bristles of Pin2/+ flies very short at normal room temperature, but wild type at 17oC. Homozygotes almost lethal, the few survivors having virtually no thoracic bristles. Pin2/Pin1 mutants have smaller bristles than Pin2/+ and lower viability. Pin2/+ flies carrying bw+Y have longer bristles than Pin2/+ but shorter than wild type.
Grell, Feb. 1957.