Abstract
Evidence from irradiation experiments in Eurybrachis apicalis (Homoptera: Auchenorrhyncha: Eurybrachidae) leads to the conclusion that in this species, the chromosomes are monocentric. Chromosome fragments produced by X-ray irradiation do not segregate to the poles either in mitotis or meiosis, and are left behind and lost in the cytoplasm. It is probable, however, that a variety of conditions prevail in the Hemiptera, and both localized and ‘diffuse’ kinetochore activity occurs in members of the group.
