Syringogaster rufa Cresson

Marshall, S. A., Buck, M., Skevington, J. H. & Grimaldi, D., 2009, A revision of the family Syringogastridae (Diptera: Diopsoidea), Zootaxa 1996 (1), pp. 1-80 : 59-62

Syringogaster rufa Cresson

Figs. 50–53; Plates 1A–B, 3G, 4H, 5E; Map 9

Syringogaster rufa Cresson, 1912: 393 (type species of genus by original designation); Curran, 1934 (wing illustration); Papavero, 1964 (misidentification); Prado, 1969.

DESCRIPTION: Head orange except darker ocellar tubercle. Vertex evenly and strongly convex at middle. Ocellar triangle shining, bare, bordered on each side by a row of four small inclinate bristles; strongly tapered and triangular, anterior apex separated from frontal margin by at least 3X scape width; remainder of frons tomentose and dull. Ocellar bristles strong. Anteromedial surface of pedicel bare. Parafacial distinctly divided into lateral and medial strips; shining vibrissal angle with thin black bristles. Gena and subgena subequal in height, gena with a row of fine black bristles. Supracervical collar shorter than pronotum, with a dense dorsomedial patch of sensilla.

Thorax: Pronotum orange, with a strong anterolateral carinae on each side; antepronotum and propleuron shining, notum otherwise dull, tomentose and mostly sparsely setulose, setulae of dorsocentral lines longer and more conspicuous than in other species, longest ones as long as rays of arista; anterior half of notum orange except for small, black, subquadrate humeral pit; posterior corners slightly darker in front of postalar callus, scutellum yellow. Notopleural carina and humeral carina small but distinct; postpronotum dull tomentose and sparsely setulose; black humeral carina short, restricted to anterior face of humeral pit; supraalar carina indistinct, tomentose. Laterotergite with carinate anterior margin raised well above anepimeron. Pleuron orange except for narrow, more or less darkened depressed area along margin between meron and metapleuron (extent of area varies between specimens), subspiracular ridge, and postmetacoxal bridge just above hind coxae. Upper posterior corner of anepisternum densely covered with long pale setulae, lower anepisternum, katepisternum and anepimeron sparsely covered with fine bristles, mesopleuron otherwise shining and bare. Anterior prespiracular process forming a narrowly triangular tooth extending posteriorly (in some specimens the apex of this tooth is dark); posterior prespiracular process forming a strong, shining ridge along anterior face of spiracle. Subspiracular ridge weakly developed, with a low, bare anterior lobe and a tomentose posterior lobe. Fore coxa, trochanter and base of femur yellow to pale brown, bristles long and pale, longer in male. Posteroventral margin of fore femur with long thin yellow bristles anteroventral margin bare. Mid femur white basally, rest of femur pale brown; tibia brown on basal half, yellowish on distal half. Mid tarsomeres 1–3 and basal half of tarsomere 4 with antero- and posteroventral sawlines. Hind femur with a white basal ring followed by a dark brown ring of similar length; hind tibia dark brown on basal ¾, pale distally. Hind femur concave dorsobasally, convex for balance of dorsal surface; anteroventral row of 7–9 spine-like bristles extending over more than distal 1/2 of femur, posterior row shorter. Hind tibia not at all produced apicoventrally. Hind tarsomeres 1–4 with sawlines, those on tarsomere 4 extremely shortened. Metanotum well developed, orange except for black points of articulation with mesonotum and tergite 1.

Wing clear with large and dark patches over all crossveins, patches over basal crossveins coalescing into a narrow band that does not reach leading edge of wing; a narrow discal band encompassing apex of R 2+3 and extending forward along vein M to meet dark patch over r-m and extending to dark patch over dm-cu but not extending to hind margin of wing. Fork of CuA usually lined up with bm-cu; A 1 +CuA 2 extending to wing margin, CuA 1 extending to wing margin. R 2+3 running to costa at a very oblique angle, not distinctly turned up near apex. Cell r 4+5 gradually widening beyond r-m, almost parallel sided distal to r-m, not abruptly tapered to r-m; r-n almost as long as dm-cu; dm-cu strongly convex.

Abdomen: Abdomen reddish brown, tergites 4 and 5 sometimes darker laterally. Syntergite 1–3 elongate, tergites 1 and 2 almost parallel-sided. Tergite 1 weakly punctate; tergites 2 and 3 fused but delineated by a distinct suture, shining, bare except for scattered setulae, with indistinct longitudinal wrinkles.

Female terminalia: Four spermathecae in two pairs, each pair made up of close but distinctly separated, dark, acorn-shaped spermatheca; each spermatheca ringed by grooves, cylindrical cap about a third as long and wide as theca.

Male terminalia: Tergites 5 and 6 unmodified, ventrolateral margins straight, spiracles 5 in membrane, spiracles 6 in tergite. Both sternites 5 and 6 reduced to a pair of small, pale sclerites, each with 2–4 long bristles; synsternite 7+8 narrow but forming a complete ring, spiracles in lateral margins of ring although right spiracle slightly lower. Postabdomen entirely pale. Epandrium slightly wider than long. Cercus almost sessile, much smaller than the broad, mitt-shaped surstylus; latter with longest bristles as long as surstylus. Hypandrium entire, lacking breaks or weakening; anterior U-shaped portion relatively slender, lacking anterior apodeme; hypandrial bridge narrow but not weakened medially; ventral hypandrial lobe stout but not inflated, parallel-sided and with ca. five stout bristles at apex. Pregonites slightly asymmetrical, very characteristic and of peculiar shape: ventral process unusually long, accommodated by shallow dorsal groove of basiphallus, basomedially with small tooth; median process strongly sclerotized, triangular with acute apex; posterodorsal process broadly rounded, somewhat lamellate, with submarginal carina on left pregonite only. Basiphallus narrowly cylindrical at base, greatly expanded and asymmetrical distally, right apicolateral corner more prominent than left one; distiphallus directed sinistrally, basal part broadly U-shaped with one arm curved up left side of postabdomen, distal part with a small, medial, finger-like process and a very large, sickle-shaped process approximately the same size as the basal part of the distiphallus.

TYPE MATERIAL: Holotype ♀ and two paratypes ♂ ( ANSP): COSTA RICA. Río Surubres , Bonnefil Farm, 800’, 16.x.1909, P.P. Calvert. We have seen only photos of the holotype and two paratypes provided by J. Weintraub ( ANSP).

MATERIAL EXAMINED: COSTA RICA. Puntarenas, Osa Peninsula, Corcovado N.P., San Pedrillo , 1–50 m, 8º37.5’N, 83º44.1’W, 12–14.viii.2001, trailside leaves and yellow pans, M. Buck, K.N. Barber, S.A. Marshall, J. Skevington (10♂, 11♀, DEBU; 3♂, CNCI) ; Bosque Esquinas, A.C. Osa , 200 m, v.1994, M. Segura (1♂, INBC) ; Heredia, La Selva Biological Station , 10.43ºN, 84.02ºW, 6–9.vii.1993, pan traps, B. Brown (1♀, LACM) ; “Surrubres” [= Surubres] (1♀, CNCI, Syringogaster rufa det. Kertész) ; Heredia, 5.5 km S Pto. Viejo , 4–5.iii.1991, secondary forest, B.J. Sinclair (1♂, CNCI) ; Cartago, 5 km E Turrialba, Reventazón Gorge , 10.xi.1980, J. Wooley (1♂, 1♀, CSCA) . ECUADOR. Pichincha, 47 km S Sto. Domingo, Río Palenque Station , 250 m, 17–25.ii.1979, S.A. Marshall (1♂, DEBU) . PANAMA. Barro Colorado Island , 24.vii.1963, D.Q. Cavagnaro & M.E. Erwin (1♂, AMNH) ; Barro Colorado Island , viii.1938, F.M. Hull (1♀, CNCI) .

COMMENTS: Curran (1934) illustrated a wing of S. rufa from Barro Colorado Island, Panama.