Diopsis (Diopsidae, Diptera) with unusual wing spots: two new species from Malawi with a longer eye span in females than in males

Diopsis malawiensis spec. nov. and D. vanbruggeni spec. nov. are described from Malawi. Subgeneric grouping of Diopsis Linnaeus, 1775, is briefly discussed, but the genus awaits revision. A redescription is given of Diopsis micronotata Brunett i, 1926, from the D.R. of Congo, as this species might be confused with D. vanbruggeni. The two new species and D. micronotata are closely related and are tentatively placed in the absens Brunett i group. Diopsis surcoufi Séguy, 1955, from Mozambique and Tanzania, is redescribed because of its superficial resemblance to D. malawiensis. All four species are characterised by tiny, but distinct, apical or subapical wing spots. In D. malawiensis, D. micronotata and D. vanbruggeni, eye span is, in absolute and relative terms, slightly longer in females than in males. Sexual dimorphism in Diopsidae, as related to eye span, is briefly discussed.