The adjective of apex. Example: 'Arista commonly bare on apical half' means that the second half of the arista (starting from the third antennal segment) is bare. Opposite of basal.
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?