The fine structure of the trifoliate process of three species of Atherigona were studied. The outer surface of the lateral lobe of the process for the three species, A. bedfordi, A. hyalinipennis and A. secrecauda is covered with a dense mat of hairs. There are spine-like outgrowths on their inner surface referred to as “commasets” as well as some unusual sensilla on the rim of the lateral lobe and the section connecting the lobes to the stem. These structures showed inter-specific variation. The stem of the process is glabrous and granulate in A. bedfordi and A. secrecauda, but sparsely pilose in A. hyalinipennis.
