Following radiation treatment with approximately 2400 r., young C. tarsalis male adults fathered stocks which produced large numbers of inviable embryos over 15 generations. Cytological examinations of the primary spermatocytes of viable offspring indicated that in some cases this reduction in egg hatch was due to reciprocal translocations or other inherited chromosomal aberrations. This preliminary investigation suggests that inherited chromosomal anomalies, with possible application in control programs, can be induced and successfully maintained in this species.