In various ants: a worker of a distinct form having an enlarged and malformed thorax.
Originally supposed to result from abnormal development associated with nest parasitism by certain beetles, the condition is now thought to be caused in most cases by an infectious disease of the labial glands..
Origin
Late 19th century (in an earlier sense). From pseudo- + ancient Greek γυνή woman, wife, in sense 1 after French pseudogyne parthenogenetic female insect, in sense 2 after German Pseudogyne, use as noun of feminine of pseudogyn (adjective).