Worker ants ofPolyrhachis (Cyrtomyrma) ?doddi collectively discharge the secretions of their large mandibular glands when their nest is disturbed. The major glandular compounds of workers are 6-methylhept-5-en-2-one and phenylacetaldehyde oxime. Other components identified are mellein, 6-methylhept-5-en-2-one oxime, phenylacetonitrile, phenyiacetaldehyde, benzaldehyde, and several alkanes and alkenes. The mandibular gland secretions of queens differ from those of workers only quantitatively. Large queens have considerably more of most components, the small queens have much less of volatile components. There is a pronounced sexual difference: the major components of the male's secretions are octanoic acid and mellein, with geranic acid, 8-heptadecene, 2-methylbutanoic acid, and 9-nonadecene present in lesser amounts. Workers ofP. ?doddi also have unusually large Dufour's glands containing a large array of hydrocarbons, of which tridecane is the major component, but α-farnesene, pentadecane, and heptadecene are also present in large quantities.