Sterility and lethality in crosses involving two translocation heterozygotes of the Germay cockroach, Blatella germanica (L.).

Productivity in crosses involving two independent reciprocal translocations in Blattella germanica are reported. Lethal effects alone could not account for the reductions in hatch since completely unproductive crosses occurred frequently. The latter are attributed to the inability of reduced numbers of viable embryos to force open the egg case. The implications for genetic control of the joint dominant effects from embryonic trapping and translocation semisterility are discussed.