The Dufour gland secretion of M. scabrinodis is largely composed of the same farnesene homofarnesene and bis-homofarnesene isomers found earlier in M. rubra, a C18 Tris-homofarnesene has also been identified. The hydrocarbons found in M. rubra are absent from M. scabrinodis except for small amounts of pentadecane, pentadecene, heptadecane and nonadecane. Methanol, ethanal, ethanol, acetone, butanone, butenone and 1-butanol are also present in small quantities. Further evidence has been obtained from the dehydration of pure nerolidol isomers by a new method, to show that the Myrmica ants produce (Z,E)-α-farnesene. © 1979.