Revision of the genus Macrostomus Wiedemann (Diptera, Empididae, Empidinae). IV. The amazonensis species-group Author Rafael, José Albertino Author Cumming, Jeffrey M. text Zootaxa 2015 3947 1 109 121 journal article 10.11646/zootaxa.3947.1.7 157445af-8a6b-4ebd-8f19-7a1fd783268b 1175-5326 237979 54A83A1C-7F6E-416C-88C3-E4D3916E1698 Macrostomus amazonensis species-group Description. Male . Head narrowly dichoptic. Frons shiny black, varying in width from ¾ to approximately subequal to anterior ocellus width. Ocellar tubercle slightly protuberant with one pair of ocellar setae. Face less shiny black than frons, width approximately half of anterior ocellus width, slightly wider at apex; apex slightly gray pruinose. Postcranium black, gray pruinose. Antenna velvety black with postpedicel pubescent and unisegmented, sometimes pedicel somewhat yellow. Proboscis yellow, brown at base, approximately as long as or slightly longer than head height. Palpus brown or yellow. Thorax shiny, black, yellow or both, more gray-brown pruinose on posterior disc of scutum, scutellum, postscutellum, laterotergite and sparsely on mesopleuron. Thoracic chaetotaxy: 2–5 antepronotals; 1 postpronotal stout and 2–3 minute; 3–4 pairs of dorsocentrals; 1 supraalar presutural; no supra-alar postsutural; 1 postalar stout and 1 minute; 1–3 proepisternals; 1 notopleural stout and 1 minute; 1–2 pairs of scutellars, when 2 present outer pair weaker; 3–6 slender katatergitals with anterior row longer. Legs shiny, predominantly yellow; fore tarsomeres 1–4 whitish apically and 1–2 rather yellow banded medially. Hind femur with 1 anteroventral seta at distal third, sometimes absent. Hind tibia ( Fig. 1 ) with 4 dorsal setae and hind tarsomere 1 with 1 longer dorsal seta. Wing ( Figs 54, 56, 58, 60, 62 ) brown infuscated on pterostigma and apex of cell r2+3. Veins M1, M2 and A1 evanescent; cell dm elongate and truncate. Halter brown to yellow, partially white at knob. Abdomen shiny black, sometimes yellow on basal segments and on terminalia. Tergite 1 ( Fig. 15 ) narrow, tergites 2 and 3 with no slender longer setae posterolaterally. Terminalia with tergite 8 short, not projected posteriorly ( Figs 2 , 11 , 19 , 30 , 45 ), sinuose with shallow to notched indentation ( Fig. 30 ), or not, along anterior and posterior margins. Epandrium with anterodorsal and posterodorsal lobes of same height ( Figs 3 , 20 , 31 , 46 ), or posterodorsal lobe higher ( Figs 12 , 39 ). Hypandrium with apex somewhat simple with variable setae ( Figs 5 , 22 , 33 , 41 , 47 ), or no setae ( Fig. 14 ). Anterior cercus of variable shape; posterior cercus elongate, simple or with secondary protuberances, usually upwardly directed ( Figs 3 , 12 , 20 , 31 ); median cercus always membranous with long setae ( Figs 3 , 12 , 20 , 31 ); cercal bridge usually narrow ( Figs 13 , 21 ). Ventral projection of cercus thin ( Fig. 12 ) or swollen ( Figs 47, 48 ), with or without setae distally. Ejaculatory apodeme with very short dorsal lamella. Female . Head dichoptic. Frons approximately as wide as anterior ocellus width. Width of face half of anterior ocellus width. Fore tarsomeres 1–4 not white distally; hind tibia with or without pinnate setae dorsally and ventrally. Wing ( Figs 55, 57, 59, 61, 63 ) approximately as wide as in male, generally with same infuscation pattern. Terminalia ( Figs 6–9 , 15–17 ). Sternite 8 of variable shape. Genital fork with base widened and lateral arms inwardly curved or elongate ( Figs 9 , 53 ), or small with lateral arms absent ( Fig. 28 ). Genital chamber membranous to slightly sclerotized.