Drosophilidae (Diptera) of the Cook Islands Author Mcevey, Shane F. Author Polak, Michal Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45221 - 0006, United States of America text Records of the Australian Museum 2021 Rec. Aust. Mus. 2021-11-24 73 5 153 170 http://dx.doi.org/10.3853/j.2201-4349.73.2021.1770 journal article 10.3853/j.2201-4349.73.2021.1770 2201-4349 7177968 5F204B3F-03AD-459D-83F3-4D14B41A1677 Scaptodrosophila marjoryae (Harrison, 1954:105) Seventeen species of Scaptodrosophila are known from the Tropical South Pacific (TSP). During the present survey a pale brown Scaptodrosophila species with translucent or weakly pigmented setae and without thoracic vittae was collected on Aitutaki and Rarotonga. It has apical and basal scutellar setae subequal in length and is therefore not S. bryani or S. anuda (see above); it has C-index 2.11–2.23 (AM K.472185–88) and is therefore not S. scaptomyzoidea (Duda, 1923) — S. scaptomyzoidea has exceptionally high C-index in the range 4.0–4.7 ( McEvey & Dizon, 2017 ). This is not a black species or a species with blackened thorax or blackened tergites, nor is it a species with any form of thoracic banding or thoracic vittae. This effectively eliminates 12 of the remaining 14 described TSP Scaptodrosophila species. The present species appears to be very close to S. marjoryae (Harrison, 1954) previously reported only from Samoa ( Table 1 , Fig. 1 , 1500 km distant). Scaptodrosophila marjoryae closely resembles S. concolor (Bock, 1976) and S. aurochaeta (Bock, 1984) from Australia . Specimens with very similar morphology, and awaiting determination in the AM, have been examined by us from Vanuatu (AM K.380057), Moorea (McE10215 CNRS/ MNHN) ( Table 1 , Fig. 1 ) and Townsville, Australia (Schiffer’s iso-female culture CBN17, AM K.357126–45 etc.). Unfortunately we have been unable to examine S. marjoryae from Samoa but our conclusion after a comparative study of male terminalia of these similar pale brown species with translucent setae from across the TSP and northern Australia is that at least four species exist; differences exist in specimens from Rarotonga, Port Vila, Moorea, and Townsville. Only three names are available (in the TSP and northern Australia ), so types of S. marjoryae , S. concolor and S. aurochaeta must be examined before identifications can be made with confidence. In the interim, since we find no departure from Harrison’s description, we have determined the present species from the Cook Islands to be S. marjoryae and we leave open the question of possible synonymies with Australian species until further study.