(A–C′) Photomicrographs of dissected testes (T), seminal vesicles (SV), paragonia (P), and ejaculatory ducts (ED) from 4-day old male flies. (A) Canton-S and (B) Sply14a revertant with normal testes. Sply05091 mutant male with (C) one reduced testis (arrow) and (C′) two reduced testes (arrows). (D) Reduced testicular phenotype is seen in 41.4% (N=170) of the Sply05091 mutant males and rarely, if ever, in Canton-S and Sply14a revertants. Bar, 400 μm. * indicates p<0.001.