MORPHOLOGIC DEFECTS IN ANEUPLOID EGGS FROM MATINGS OF TRANSLOCATION HETEROZYGOTES OF THE GERMAN-COCKROACH (DICTYOPTERA, BLATTELLIDAE)

Aneuploid eggs from reciprocal crosses of wild type to translocation h eterozygotes involving 6 of the 11 autosomes of the German cockroach, Blattella germanica (L.), are described. Eggs were arrested early in d evelopment, either before or during formation of a segmented germ band . They were categorized roughly according to embryonic development. Se veral types of gross morphological defect in eggs from individual ooth ecae recurred in other matings of the same translocation heterozygote. The greatest similarities were between eggs from crosses of transloca tions involving the same two chromosomes. In three translocations, the frequency of advanced egg types differed in reciprocal crosses but, i n three others, no difference was apparent. It is suggested that the z ygotic genome acts earlier in the control of early embryogenesis in B. germanica, and possibly in other primitive hemimetabolans, than in ho lometabolous insects.