Diopsis mayae sp. n. (Diptera, Diopsidae), a dominant stalk-eyed fly, occurring from South Africa to Saudi Arabia

Diopsis mayae sp. n. is the sister species of the well-known West-African D. apicalis. It occurs from Egypt and Saudi Arabia down through eastern Africa to Namibia and South Africa. Both species belong to the D. apicalis species group, a relatively young branch of the Diopsidae, and separated at least 280,000 years ago. Although around 40 species still need to be described in the D. apicalis species group, D. mayae sp. n. and D. apicalis are by far the most dominant species in the group, while both species belong to the very small group of Afrotropical Diopsidae with a wide distribution. Data are presented on sexual dimorphism with respect to eye span for the new species and compared with those for D. apicalis. Both species are secondary stem-borers in rice and other Poaceae. Ecological information is presented for D. mayae sp. n. and compared with the information available for D. apicalis.