Stipomorpha simillima (Hull, 1950)

Reemer, Menno, 2013, Taxonomic exploration of Neotropical Microdontinae (Diptera: Syrphidae) mimicking stingless bees, Zootaxa 3697 (1), pp. 1-88 : 67-68

Stipomorpha simillima (Hull, 1950)

Figs 204–208 , 246 .

Microdon simillimus Hull, 1950: 611 .

Studied type specimens. HOLOTYPE. GUYANA. Male. Label 1 (small round, red-bordered): " Holotype "; label 2:"Dark forest"; label 3: "A in cop. with B"; label 4: "British Guyana: Essequibo R., Moraballi Creek. 17.X.1929. Oxf. Univ. Expedn. B.M. 1929-485."; label 5 (red): " Holotype Microdon simillima Hull ". Coll. BMNH.

PARATYPES. GUYANA. Male. Label 1 (small, round, yellow-bordered): " Paratype "; label 2: "Dark forest."; label 3: "British Guyana: Essequibo R., Moraballi Creek. 17.X.1929. Oxf. Univ. Expedn. B.M. 1929-485."; label 4 (yellow): " Paratype Microdon simillima Hull ". Coll. BMNH.

Male. Label 1: " British Guiana: / Essequibo R., / Moraballi Creek / 25.ix.1929. / Oxf. Univ. Expedn. / B.M. 1929-485."; label 2 (yellow): " Paratype / Microdon / simillima / Hull". Coll. CNC.

Additionally studied specimens. BRAZIL: 1 male, Belém, Pará, 17.V.1967, leg. Y. Sedman, coll. USNM; FRENCH GUYANA: 1 male, Crique Sapokal Degrad Laurens, 95 m., N 3°16' / W 52°41',, 26.viii–2.ix.2000, malaise trap, leg. A.E.I. Guyane, coll. J.T. Smit; PERU: 1 female, Madre de Dios, Rio Tambopata, Sachavacayoc centre, N 12°51'20.1" / W 69°22'20.1", 9–14.X.2010, malaise trap, leg. & coll. J.T. Smit; 1 female, Madre de Dios, Rio Tambopata, Sachavacayoc centre, N 12°51'46.4" / W 69°21'46.6", 14–20.X.2010, malaise trap, leg. & coll. J.T. Smit.

Redescription (based on holotype)

Adult male. Body size: 6-7 mm.

Head. Face occupying 1/4 of head width in frontal view; shining yellow with a pale brown median stripe from oral margin to just below antennae, gradually narrowing upward; face with white pilosity, a little longer around oral margin, except bare on median stripe. Gena blackish. Occiput black; black pilose dorsally, getting white laterally and ventrally. Oral cavity with hardly produced lateral margins. Frons and lunula black and short black pilose, except for bare triangular part posterior to lunula. Vertex black; black pilose. Eye very sparsely and short pilose, with pili about as long as ommati diameter, appearing bare under low magnification. Antennal fossa about as wide as high. Antenna blackish brown, except scape yellow on interior sides; scape and pedicel dark pilose; antennal ratio 4:1:3.5; basoflagellomere parallel-sided with narrowly rounded apex, with sensory pit located at 3/4 from base, within a vague groove that ranges from just before 1/2 to just after the pit; arista slender, about 2/3 of length of basoflagellomere, very shortly pilose, appearing bare under low magnification.

Thorax. Black, more brownish on pleurae. Postpronotum, scutum, postalar callus and scutellum short black pilose, except a few pale pile on scutellum (and possibly along transverse suture of scutum, but not well visible in type specimen). Scutellum semicircular, without calcars. Anepisternum more or less flat, pilose anterodorsally. Anepimeron pilose posterodorsally. Katepisternum and katepimeron bare. Calypter grey, halter yellowish.

Wing: hyaline, with faint yellowish cloud on and posterior to pterostigma and with faint dark cloud between apex of costal cell and vena spuria , and microtrichose except bare on basal 3/4 of cell br, basal 1/2 of cell bm, anterobasal 1/4 of cell cup.

Legs: brownish black, except anterior four tarsi yellow with first tarsomere more brownish. Legs black pilose, except anterior four tibiae pale pilose and hind-tibia pale pilose on basal 1/3; pile on hind-tibia a little longer than half the width of the tibia. First tarsomere of hind-tarsus as long as 1/3 of length of hind-tibia, a little wider than apex of tibia, twice as long as wide (dorsal view). Front-coxae and trochanters pale pilose; mid- and hind-coxae and -trochanters black pilose.

Abdomen. Blackish (but see diagnosis). Second segment wider than thorax, widest point at half the lentgh; third and fourth tergites strongly narrowing. Tergite 1 black pilose laterally; with anterolateral 'ridges'; with anteromedian smooth, concave area. Tergite 2 black pilose laterally, pale pilose dorsally. Tergite 3 black pilose. Tergite 4 black pilose, lateral margins with pale pilosity, which is posteriorly connected with two submedial lines of pale pile on posterior half of the tergite. Sternite 1 narrow and bare, separated from sternite 2 by a membrane of twice the width of sternite 1. Sternite 2 bare, laterally twice as wide as medially, separated from sternite 3 by a membrane of 1.5 times the median width of sternite 2. Sternite 3 and 4 pilose, not separated by membrane. Genitalia as in fig. 246.

Female. As male, except for usual sexual differences.

Diagnosis. From other Stipomorpha -species with a black thorax, S. simillima can be recognized by the following characters: face largely yellow with narrow median brown stripe, basoflagellomere about as long as or slightly shorter than the scape, anepisternum only pilose anterodorsally, katepisternum bare, structure of male genitalia. The colouration of the abdomen appears to be quite variable, from blackish in the holotype to pale brown in the paratype.

Notes. The fourth label on the holotype reads "A in cop. with B". Apparently the male holotype has been collected in copula with a female that has later been labelled as specimen B. The whereabouts of this female are unknown. In the original description Hull (1950) only mentions two male paratypes, one of which is present in the BMNH collection.

Distribution. Known from Guyana, French Guyana, Brazil and Peru.

Figures

FIGURES 201 – 211. 201 – 203. Stipomorpha puerilis female (holotype). 201. habitus dorsal; 202. habitus lateral; 203. head frontal. 04 – 208. Stipomorpha simillima male (holotype). 204. habitus dorsal; 205. habitus lateral; 206. head frontal; 207. head lateral; 208. wing. 209 – 211. Stipomorpha spuria male (holotype). 209. habitus dorsal; 210. habitus lateral; 211. face frontal.

FIGURES 246 – 251. Stipomorpha, male genitalia latera. 246. S. simillima (holotype); 247. S. spuria (holotype); 248. S. tenuicauda (Bolivia, coll. RMNH); 249. S. trigoniformis (holotype); 250. S. wheeleri (paratype); 251. S. zophera (holotype).