ABSTRACT
Abstract The first gynandromorph of the insect order Zoraptera is reported. A gynandromorph of Zorotypus brasiliensis Silvestri is described from a likely parthenogenetic population in the Atlantic Forest around the border of the Brazilian states of Minas Gerais, Rio de Janeiro, and São Paulo. As has been previously surmised for this species, the sample consisted of only females, tending to support the hypothesis of thelytokous parthenogenesis for this population. The gynandromorph is largely female in outward appearance, but exhibits male secondary sexual traits on the left side of the apical abdominal segments. The left (male) antenna consists of antennomeres of different proportions to those of the right (female) antenna. The internal genitalia and associated sclerites, however, are female although some are augmented in their form relative to normal-type females. Comments are made on possible factors resulting in the development of the gynandromorph. This is the 16th insect order with gynandromorphism reported.