The taxonomic significance of eye pattern in female Tabanidae (Diptera)

Female eye patterns are illustrated for 86 of 92 species and varieties of Tabanidae known from Tennessee. The figures show the relative size, shape, presence or absence of pattern, and shape and position of pattern on the corneal surface of the eyes. The absence of eye pattern among all individuals of 5 genera implies that the unicolorous condition is primitive. Genera that normally exhibit patterned eyes may have some unicolorous representatives in which the condition is thought to be secondarily derived. Seven of the 8 genera from Tennessee that exhibit patterned eyes may be separated by eye pattern alone. Possible phylogenetic relationships, based on eye pattern in conjunction with other characters, are presented for species of the genus Tabanus.