Revision of the genus Macrostomus Wiedemann (Diptera: Empididae: Empidinae). I. The ferrugineus species-group Author Rafael, José Albertino Instituto Nacional de Pesquisas da Amazônia, Coordenação de Entomologia, Caixa Postal 478, 69011 - 970, Manaus, Amazonas, Brazil. E-mail: jarafael @ inpa. gov. br Author Cumming, Jeffrey M. Invertebrate Biodiversity, Agriculture and Agri-Food Canada, K. W. Neatby Bldg, C. E. F., Ottawa, Ontario, Canada K 1 A 0 C 6. E-mail: jeff. cumming @ agr. gc. ca text Zootaxa 2009 2009-04-06 2064 1 39 56 https://biotaxa.org/Zootaxa/article/view/zootaxa.2064.1.4 journal article 10.11646/zootaxa.2064.1.4 1175-5326 5321572 Macrostomus fuscithorax , n. sp. ( Figs. 1a–h , 8 ) Diagnosis. Thorax and abdomen shining black, legs predominantly yellow; postcranium black with gray pruinescence; male tergite 8 acute distally; vein CuA 1 shorter than dm-cu vein. Female without pinnate scales on hind tibia; wing approximately as wide as male wing, rather hyaline. Description. Holotype male. Frons approximately one third anterior ocellus width. Face slightly wider than frons only at ventral margin. Postcranium entirely black. Antennae lost. Palpus brown. Thorax shining black with gray-brown pruinescence more distinct on disc of scutum. Setae: 4 dorsocentrals; 1 supra-alar presutural; scutellar lost; 3–5 antepronotals; 1–3 tiny proepisternals; 3–5 katatergitals. Legs (only hind leg present) yellow with distal tarsomeres 3–5 or 4–5 brown; hind tibia with one distal slender setae; first hind tarsomere with no slender setae dorsally. Wing with pterostigma brown and distal patch slightly brown infuscated ( Fig. 1a ). Halter with stem light yellow, knob partially brown. CuA 1 vein shorter than dm-cu vein. Abdomen shining black. Tergite 8 ( Fig. 1b ) with a thin distal projection. Epandrium with posterodorsal protuberance slightly longer than anterodorsal protuberance ( Fig. 1c ). Anterior cercus rather short; posterior cercus with many anterodorsal and slender dorsal setae and a internal small distinct ramification ( Fig. 1d ). Hypandrium ( Fig. 1e ) with a few setae medially, a paired rounded and relatively wide protuberance distally, and an acute subapical process medially. Size. Body length 2.5 mm ; wing length 2.7 mm . Female. Frons approximately anterior ocellus width; face narrower than frons, approximately half anterior ocellus width. Legs without pinnate scales. Tergite and sternite 8 ( Figs. 1f–g ) as described for M. ferrugineus species-group. Genital fork ( Fig. 1h ) with well sclerotized T-shaped rod. Size. Body length 3.2 mm ; wing length 3.3 mm . Geographical records. Brazil (Amazonas state), Fig. 8 . FIGURE 1 . Macrostomus fuscithorax , n. sp. , paratypes. A–E, male; A , wing apex; B , tergite 8, dorsal view with right setae omitted; C , epandrium and cercus, lateral view; D , detail of posterior cercus; E , hypandrium and phallus, lateral view. F–H : female. F , Tergite and sternite 8, lateral view; G , sternite 8, ventral view; H , genital fork, ventral view. Abbreviations: DP, distal protuberance; SP, subapical process. Scales: A = 0.5 mm; B–G = 0.2 mm; H = 0.1 mm. Material. Holotype ♂ : BRASIL , Amazonas , Manaus, F [azenda] P[orto] Alegre , BR 174 , km 68 // 17–19.xi.1993 , F.F.Xavier ( INPA ). Paratypes . Same data as holotype ( 1♀ INPA ); Manaus, PDBFF / WWF, Proj. Bert Klein, i.1985 , Malaise, Res. 1210 ( 1♂ 2♀ INPA , male with only terminalia in glycerin, remaining of body lost; one female in glycerin); Manaus, PDBFF / WWF, Proj. Bert Klein, xi.1985 , Malaise, Res. 1301 ( 1♀ CNC ) . Holotype condition. In poor condition. Head glued in the pin; antennae lost; most legs missing with only right hind leg present; terminalia in glycerin. The other known male specimen ( INPA paratype ) is only represented by terminalia. Etymology. From Latin fuscus = black in reference to the black color of thorax. Discussion. Macrostomus fuscithorax , n. sp. appears close to M. ferrugineus (Fabricius) , M. fusciventris , n. sp. and M. melanothorax , n. sp. on the basis of the shape of male tergite 8, which is acutely projected distally. Macrostomus fuscithorax shares a black thorax with M. melanothorax ; the other species of the M. ferrugineus species-group have a predominantly yellow thorax. It differs from M. melanothorax by vein CuA 1 being shorter than vein dm-cu, by the shape of posterior cercus, the apex of the hypandrium, and by the epandrium with the posterodorsal protuberance slightly longer than anterodorsal protuberance.