1. Bettini, S. (ed.): Arthropod Venoms. Berlin-Heidelberg-New York: Springer 1978
2. Carlet, G.: Ann. Sci. nat. (Zool.) 9, 1 (1890)
3. Robertson, P.L.: Aust. J. Zool. 16, 133 (1968); Maschwitz, U., Kloft, W., in: Venomous Animals and their Venoms (Bücherl, W., Buckley, E.E., eds.). New York-London: Academic Press 1971; Dufour's gland opening is here correctly described outside the sting base in the Vespidae, but incorrectly inside it in the Apidae
4. Schlusche, M.: Zool. Jb. (Anat.) 61, 77 (1936); Snodgrass, R.E.: Anatomy of the Honey Bee. Ithaca, N.Y.: Comstock 1956; de Lello, E.: J. Kansas Entomol. Soc. 49, 85 (1976)
5. Forel, A.: Z. Wiss. Zool. 30, 28 (1878); Janet, C.: Etudes sur les Fourmis, les Guêpes et les Abeilles, Note 17. Paris: Carré & Naud 1898