The beach flies of the Mascarene Islands (Diptera: Canacidae: Tethininae) Author Munari, Lorenzo c / o Entomology Section, Museo di Storia Naturale, S. Croce 1730, Venezia, Italy. Author Kirk-Spriggs, Ashley H. Senior Curator in Charge of Diptera and Siphonaptera, Department of Life Sciences, Natural History Museum, Cromwell Road, London SW 7 5 BD, United Kingdom. Author Mcgregor, Gillian K. Geography Department, Rhodes University, Grahamstown 6140, South Africa. text Zootaxa 2020 2020-09-22 4853 2 183 198 journal article 9109 10.11646/zootaxa.4853.2.2 665c72da-8a91-438a-ac00-4d39ce709306 1175-5326 4410564 5FCB7B3D-DE8C-441D-96A4-5B71D73415B1 Dasyrhicnoessa insularis ( Aldrich, 1931 ) Figs 10 , 16 , 24 , 27 , 32 . Distribution . Afrotropical : Cameroon , Madagascar , Mascarenes ( La Réunion *, Mauritius *, Rodrigues *), Nigeria , Seychelles ( Mahé ), Sierra Leone . Australasian/Oceanian : American Samoa (Tutuila), Australia ( Queensland ), Austral Islands, Bismarck Islands (Dyaul), Canton Island, Caroline Islands (Ponhpei, Chuuk , Yap , Palau ), Fiji Islands (Ovalau, Suva, Vanua Balavu, Viti Levu),? French Polynesia (Society Islands: Moorea), Hawaii (French Frigate Shoals, Hawaii, Hilo, Kahoolawe, Kauai, Lisiansky, Maui, Midway Atoll , Molokai, Oahu, Pearl and Hermes Reef), Kiribati ( Butaritari , Makin , Eita, Tarawa , Abemama ), Line Islands (Christmas), Mariana Islands ( Saipan , Tinian ), Marquesas (Hivaoa, Nuku Hiva), Marshall Islands ( Majuro , Japtan, Parry, Lib , Jibu, Jaluit , Namorik ), Palmyra Island, Pitcairn Island , Rapa Island, Society Islands (Bora Bora, Raiatea, Tahiti), Vanuatu (Erromanga, Aneityum), Wake Island . Nearctic : Bermuda , United States ( Florida ). Neotropical : Bahamas (South Bimini ), Belize , Brazil ( Ceará , Paraná , São Paulo ), Mexico ( Tabasco ), West Indies ( Cuba , Dominica , St. Kitts , St. Lucia , St. Vincent ). Oriental : Chagos, Indonesia ( Sulawesi , Ternate ). Material examined (all “A.H. Kirk-Spriggs & B.S. Muller, sweeping intertidal zone and coastal vegetation”, unless otherwise stated). La Réunion : 1♀ , Grande Anse , 21°22′17″S , 55°33′00″E , 26.x.2015 , 0–12 m , M.J. Ebejer, general sweeping; secondary forest, intertidal rocks & coral beach (deposited MJEC ) ; 1♂ , St.-Louis , Rivière St.-Étienne , 21°17′54″S , 55°24′07″E , 0–9 m , 18.x.2015 , M.J. Ebejer, general sweeping; intertidal rocks & vegetated gravel plain (deposited MJEC); 1♀ , St.-Pierre , Pointe de Pont , 21°20′51″S , 55°28′52″E , 0–6 m , sweeping intertidal rocks and coral beach, 13.xi.2015 , A.H. Kirk Spriggs. Mauritius : 14♂ , 11♀ , Black River , Le Morne Brabant , 20°27′32″S , 57°19′42″E , 1–3 m , 28.i.2018 ( 1♀ deposited LMC) ; 63♂ , 35♀ , Black River , Petite Case Noyale , 20°24′23″S , 57°22′10″E , 1–3 m , 28.i.2018 ( 2♂ deposited LMC) ; 3♂ , 4♀ , Black River , Tamarin , 20°19′41″S , 57°22′33″E , 1–3 m , 28.i.2018 ; 23♂ , 86♀ , Grand Port , Grand Sable , 20°19′12″S , 57°46′12″E , 1–3 m , 27.i.2018 ( 2♂ , 1♀ deposited LMC) ; 8♂ , 8♀ , Grand Port , Pointe d’Esny , 20°25′28″S , 57°43′22″E , 1–3 m , 27.i.2018 ( 1♀ deposited LMC) ; 4♂ , 4♀ , Grand Port , Vieux Grand Port , 20°22′23″S , 57°42′48″E , 1–3 m , 27.i.2018 ( 1♂ deposited LMC) ; 4♂ , 1♀ , Pamplemousses , Le Goulet , 20°06′14″S , 57°31′02″E , 1–3 m , 30.i.2018 ; 9♂ , 12♀ , Pamplemousses , Tombeau Bay , 20°08′00″S , 57°29′54″E , 1–3 m , 30.i.2018 ( 1♀ deposited LMC) ; 2♀ , Pamplemousses , Trou aux Biches, 20°02′36″S , 57°32′14″E , 1–3 m , 29–30.i.2018 ; 2♂ , 6♀ , Rivière du Rempart , Pointe des Lascars , 20°05′14″S , 57°42′26″E , 1–3 m , 31.i.2018 ; 5♂ , 3♀ , Savanne , Bel Ombre , 20°30′00″S , 57°23′34″E , 1 m , sweeping coastal rocks and sandy beach, 11.xii.2016 ( 1♂ deposited LMC) ; 3♂ , 2♀ , Savanne , Bel Ombre , 20°29′32″S , 57°22′42″E , 1–3 m , 26.i.2018 ; 2♀ , Savanne , Riambel , 20°31′09″S , 57°30′25″E , 1–3 m , 26.i.2018 . Rodrigues : 2♂ , 2♀ , Anse aux Anglais , 19°40′15″S , 63°26′19″E , 1–3 m , 10.ii.2018 ( 1♂ , 1♀ deposited LMC) ; 2♀ , Anse Mourouk , 19°44′23″S , 63°27′53″E , 1–3 m , 10.ii.2018 ; 15♂ , 11♀ , Baie du Nord , 19°42′33″S , 63°22′20″E , 1–3 m , 9.ii.2018 ( 1♀ deposited LMC) ; 1♀ , Île Michel , 19°44′43″S , 63°24′13″E , 1–3 m , 10.ii.2018 ; 2♀ , Plaine Corail , 19°46′05″S , 63°22′36″E , 1–3 m , 9.ii.2018 (all deposited BMSA, unless otherwise stated). Comments : A common pantropical beach fly. In this species the colour of the thorax often exhibits strong variation. The following range of variation has been observed in specimens from different world sites: mesonotum entirely yellow to blackish, sometimes scutum dark brown and scutellum yellow only at margin; in a few cases, scutum dark brown and scutellum predominantly yellow. Though rather infrequent, some transitional forms occur in formerly studied specimens ( Munari 2002 ). The above is not corroborated by the material from the Mascarenes, which does not exhibit significant variation in mesonotal colour, the yellow or sometimes yellowish fulvous colours being invariably present, to a greater or lesser extent on the scutum. Similar to other Indo-Pacific congeners, the posteroventral armature of the male mid femur is formed of a long row of regular, spine-like setae, gently decreasing in size towards the apex of the femur.