FERREIRA A. Contribution to the knowledge of cytology of two species of Brazilian scorpions: Opisthacantus manauarensis, Ferreira, 1967 (Scorpiones, Scorpionidae) and Bothriurus asper araguaie (Scorpiones, Bothriuridae). Anais da Academia Brasileira de Ciências. v. 40, p. 97-99, 1968.