Early events in spermatogenesis, from meiosis to `onion' stage spermatids, appear normal in unc^unspecified mutants. However, in mutant elongating spermatid cysts, nuclei are dispersed along the flagellar bundle and are frequently separated from their centriole adjuncts in mutant elongating spermatid cysts and the number of axoneme profiles in each cyst is reduced by an average of 73% (17/64 intact axonemes, n=5). Some of the remaining axonemes appear unaffected, but many show defects ranging from a single break to complete disruption of the axoneme into its constituent microtubule doublets. In unc^unspecified mutants the cilia extending from the sensory processes of antennal olfactory neurons are missing or truncated. The scolopidial cilia of femoral chordotonal organs in these flies are also missing or truncated. Transverse sections of the bases of these cilia show some broken rings in the distal part of the basal body. Proximal basal bodies, ciliary rootlets and non-neuronal sensory structures are not visibly affected. Spermatocyte centrioles in unc^unspecified mutants have a similar ultrastructure to wild-type, with with microtubule triplets clearly present, but both the centrioles are shorter.