Stipomorpha mendax, Reemer, Menno, 2013

Reemer, Menno, 2013, Taxonomic exploration of Neotropical Microdontinae (Diptera: Syrphidae) mimicking stingless bees, Zootaxa 3697 (1), pp. 1-88 : 62-63

Stipomorpha mendax spec. nov.

Figs 182–185 , 242 .

Studied type specimens. HOLOTYPE. SURINAM. Male. Label 1: “Marowijne, near Perica, E-W verbinding, road 21. 25 km E of Commewijne river. Malaise trap. 6–20.VIII.1997. Leg. B. de Dijn. Coll. RMNH.

PARATYPES (all in coll. RMNH). SURINAM: 1 male, Paramaribo, Charlesburg, Krepi, 21.I.1964, leg. D.C. Geijskes; 1 male, Paramaribo, Ma Retraite, 14.I.1964, leg. D.C. Geijskes; 1 male, Paramaribo, Ma Retraite, 9.II.1964, leg. D.C. Geijskes; 1 female, Kwatta, 1.II.1964, leg. D.C. Geijskes.

Additionally studied material. FRENCH GUYANA, 1 female, Montagne de Kaw, Camp Patawa, 11.XII.2002, leg. V. Soon, coll. RMNH.

Description (based on holotype)

Adult male. Body size: 6 mm.

Head. Face occupying about 1/4 of head width in frontal view; shining yellow with vague, narrow median dark vitta; with whitish pilosity, most dense sublaterally and ventrally, very sparse medially; with narrow strip of white pubescence along eye margins. Gena hardly developed, eyes almost directly bordering oral margin; yellow. Lateral oral margins not produced; not reaching below eye margin in lateral view. Frons about as long as width of lunula; brown; yellow pilose laterally. Vertex shining black; black pilose. Occiput black; yellow pilose dorsally, white pilose ventrally. 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 brown. Antennal ratio approximately as 3:1:3.5; basoflagellomere parallel-sided with rounded apex. Arista slender, about 2/3 of length of basoflagellomere.

Thorax. Scutum black dorsally, with margins widely yellow; yellow pilose, except for two patches of black pile posterior to transverse suture. Postpronotum, postalar callus and scutellum yellow and yellow pilose. Scutellum without calcars; slightly sulcate apicomedially. Anepisternum weakly convex, without distinction between anterior and posterior part; yellow; yellow pilose anteriorly, bare posteriorly. Anepimeron brownish; yellow pilose dorsally, bare ventrally. Katatergum and anatergum brown; long and short microtrichose, respectively. Katepimeron yellow; bare. Katepisternum brown; bare. Calypter and halter yellow.

Wing: hyaline, without colouration, microtrichose except bare basally on cell r1 along vein RS, on basal 3/4 of cell br, posterobasal 1/2 of cell bm, basomedian 1/6 of alula.

Legs: Yellow, except hind tibia blackish with narrowly yellow base and first three tarsomeres of hind tarsus brown; yellow pilose, except tarsi dorsally black pilose and hind tibia long black pilose on apical 3/4. Coxae and trochanters yellow and yellow pilose.

Abdomen. Yellow and short yellow pilose. Second tergite slightly wider than thorax, widest at basal 1/3; third and fourth tergites much narrower. Sternites yellow; sparsely yellow pilose; sternite 1 bare. Genitalia as in fig. 242.

Etymology. The name mendax (Latin for lying, deceiving) was chosen in analogy of the names fraudator (Latin for cheating, deceiving) and spuria (Latin for false), two very similar-looking species of Stipomorpha.

Diagnosis. Orange-brown species with black vertex, very similar in size and colouration to S. fallax , S. fraudator and S. spuria . This species is keyed out in the key three times, because of variability in microtrichosity on the alula, variability in overall colouration and colouration of pilosity, and because of sexual dimorphism in wing colouration. In some specimens the alula is entirely microtrichose, while in others it has a small bare area basomedially. The only female identified as this species (see additionally studied material) differs from the males in the presence of a faint whitish cloud in the apical half of the wing (view against dark background). In other characters it is similar to the male.

Other varying characters: in some specimens the vertex is black pilose (as in the holotype), in others it is yellow pilose. The extent of black pile on the scutum also varies, as well as the extent of dark colouration on the abdomen. However, no discrete differences were found and the genitalia are similar in all male specimens.

Distribution. Only known from Surinam.

Figures

FIGURES 173 – 185. 173 – 174. Stipomorpha mackiei male (holotype). 173. head frontal; 174. head lateral. 175 – 176. Stipomorpha, alula. 175. S. mackiei; 176. S. tenuicauda. 177 – 181. Stipomorpha maculipennis male (holotype). 177. habitus dorsal; 178. habitus lateral; 179. head frontal; 180. head lateral; 181. wing. 182 – 185. Stipomorpha mendax male (holotype). 182. habitus dorsal; 183. habitus lateral; 184. head frontal; 185. head lateral.

FIGURES 240 – 245. Stipomorpha, male genitalia. 240. S. mackiei (Surinam, coll. RMNH); 241. S. maculipennis (holotype); 242. S. mendax (holotype); 243. S. micromidas (Costa Rica, coll. INBIO); 244. S. mixta (Guyana, coll. BMNH); 245. S. panamana (holotype).