Plural: setae. Structure on the surface of the insect body, often referred to as hairs or bristles. A seta may easily be lost but has a prominent socket (alveolus) which is raised on one side if the seta is slanted. Setae are usually connected to nerves and have a sensory function.
Does someone has a scan of Nartshuk E.P. 2003. Key to families of Diptera (Insecta) of the fauna of Russian and adjacent countries. Proceedings of the Zoological Institute Vol. 294: 1-252 for me?