Ubristes ictericus, Reemer, Menno, 2013

Reemer, Menno, 2013, Taxonomic exploration of Neotropical Microdontinae (Diptera: Syrphidae) mimicking stingless bees, Zootaxa 3697 (1), pp. 1-88 : 80

Ubristes ictericus spec. nov.

Figs 256–260 .

Studied type specimens. HOLOTYPE. BRAZIL. Male. Label 1: "Belem, Para / Brazil / 1-VI-1967 / Coll. Y. Sedman"; label 2: "IN APEG"; label 3 (red): " HOLOTYPE [male sign] / Ubristes ictericus / M. Reemer"". Coll. USNM.

PARATYPE. BRAZIL. Female. Same label data as holotype, except label 3: "new species 3"; label 4 (yellow): " PARATYPE [female sign] / Ubristes ictericus / M. Reemer". Coll. USNM.

PARATYPE. ECUADOR. Female. Label 1: " ECUADOR: Sucumbios / Sacha Lodge, 0.5°S. / 76.5°W. 270 m. 27VIII–10XI / 1994, Hibbs, ex: malaise"; label 2: " PARATYPE [female sign] / Ubristes ictericus / M. Reemer". Coll. SEMC.

Description (based on holotype)

Adult male. Body size: 10 mm.

Head. Face occupying about 1/2 of head width in frontal view; yellow, with very narrow, brown median line on lower 2/3; entirely white pilose. Gena yellow. Lateral oral margins produced. Frons and vertex yellow, except darkened posterior to lunula and on ocellar triangle; yellow pilose, except black pilose on ocellar triangle. Occiput black dorsally, yellow ventrally; yellow pilose dorsally, white pilose ventrally; whitish pollinose. 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, except scape yellowish; antennal ratio 6:1:9; basoflagellomere parallel-sided with narrowly rounded apex, with sensory pit located at 5/6 from base, within a groove that ranges from the base of the arista to close to the apex. Arista slender, about 2/3 of length of basoflagellomere.

Thorax. Scutum black, except margins widely yellowish brown; medially appressed golden yellow pilose, except for pair of black pilose patches on anterior 1/4, erect yellow pilose along margins. Postpronotum and postalar callus and scutellum yellow; yellow pilose. Scutellum yellow; yellow pilose basally, black pilose apically. Anepisternum yellowish brown; yellow pilose anteriorly and along posterior margin. Anepimeron yellow pilose on dorsal half. Katatergum and anatergum long and short microtrichose, respectively. Other pleurae bare. Calypter and halter yellow.

Wing: hyaline, with faint yellowish tinge. Microtrichose, except bare on 1st costal cell, basal 1/10 of 2nd costal cell, basally on cell r1 along vein RS, entirely on cell br except microtrichose along vena spuria , basal 2/3 of cell bm, basal 1/5 of cell cup, almost entirely on alula (only a narrow basal strip with microtrichia).

Legs: yellow, except basal 3 tarsomeres of hind leg dark brown; yellow to white pilose, except black pilose on anteroventral part of hind femur, apical 1/2 of hind tibia and dorsal part of hind tarsus.

Coxae and trochanters yellow; yellowish white pilose, except for sparse black pile apically on hind coxa.

Abdomen. Yellowish brown; yellow pilose, except black pilose posterolaterally on tergite 3 and on posterior 1/4 of tergite 4. Tergite 2 about as wide as thorax, with two lateral´bulges´halfway, which mark the maximum width of the abdomen; with long yellow pile anterolaterally, rather long yellow pile on the lateral 'bulges' and short, appressed pale pile on posterior half of tergite. Sternites with long yellow pile. Hypopygium yellowish.

Female. Body size: 9–10 mm. The female is very similar to the male, except for usual sexual differences. The paratype from Ecuador is slightly darker in colouration, with the posterior margin of the vertex dark and the hind femur and tibia somewhat darkened.

Diagnosis. Within Ubristes s.s. this is the only known species with an entirely yellow abdomen.

Distribution. Known from northern Brazil and Ecuador.

Figures

FIGURES 252 – 260. 252 – 255. Ubristes flavitibia male (holotype). 252. habitus dorsal; 253. habitus lateral; 254. head frontal; 255. head lateral. 256 – 260. Ubristes ictericus (holotype). 256. habitus dorsal; 257. habitus lateral; 258. tergite 2 dorsal; 259. head frontal; 260. head lateral.