Pelecinobaccha tristis ( Hull, 1930 ) Hull, 1930

Miranda, Gil Felipe Gonçalves, Marshall, Stephen A. & Skevington, Jeffrey H., 2014, Revision of the genus Pelecinobaccha Shannon, description of Relictanum gen. nov., and redescription of Atylobaccha flukiella (Curran, 1941) (Diptera: Syrphidae), Zootaxa 3819 (1), pp. 1-154 : 79-80

Pelecinobaccha tristis ( Hull, 1930) comb. nov.

Map 10.

Baccha tristis Hull, 1930 .— Hull, 1930: 140. Type locality: Mexico, Vera Cruz, Jalapa. Holotype male ANSP. Hull, 1949a: 195 (fig. 19, male abdomen).

Ocyptamus tristis . Thompson et al., 1976: 29 (catalog citation).

Male. Head: Black. Face with only black pile, with dense white pollen, apex of tubercle with no pollen, shiny. Lunule with small pale area above antennal insertions, central macula connected by medial vitta dorsally to frontal triangle color. Frontal triangle with silvery-white pollen laterally continuous from face. Vertical triangle with 3 rows of pile, but most pile concentrated in a single median row; ocellar triangle separated by its length from posterior eye margin. Eye contiguity slightly longer than vertical triangle length. Eye with sub-triangular indentation around level of antenna insertion. Antennal insertions confluent, ventral margin with short dorsal extension. Antenna dark brown, basoflagellomere pale on baso-ventral ⅓. Dorsal ¼ of occiput with 2 rows of simple black pile, anterior row shorter, middle 2/4 with 3–4 rows of pile, posterior row long, white and scale-like, anterior rows shorter, black and simple; ventral ¼ with 3 irregular rows of white, scale-like pile, anterior rows slightly shorter.

Thorax: Scutum black, mainly dull pollinose except with inconspicuous pair of sub-median vittae of white pollen visible from a posterior view; scutum black pilose, pile longer on notopleuron, and with anterior row of white pile with shorter pile in the middle. Scutellum black, with long, black pile, shiny pollinose, pollen differently oriented on base from remainder of scutellum, subscutellar fringe pile long and dark brown to white. Pleuron black and black pilose except mostly white pilose on katepimeron and entirely white pilose on metaepisternum, and the pile is densely arranged on the posterior anepisternum posterior margin. Plumula long and yellow. Calypter white, fringe brown. Halter stem brown, capitulum yellow.

Wing: Light brown, anterior margin diffusely darker (cells bc, c, sc, r, r1, r2+3 and bm), entirely microtrichose; alula basally 1.5 times and apically 3.5 times as broad as c cell, light brown, entirely microtrichose.

Legs: Legs dark brown, apex of femora and base of tibiae pale. Apical ¼ of metabasitarsomere to 3rd metatarsomere pale, 4th and 5th metatarsomere brown.

Abdomen: Black; 2.7 times as long as thorax. First tergite with long, erect, black pile. Second tergite long, length 3.2 times minimum width with subapical central triangular region of dull black pollen; 2nd tergite with very long, erect and black pile, except shorter and appressed dorsally, and white on baso-dorsal ⅓ and baso-lateral ½,. Third tergite trapezoidal, length ~2.3 times minimum width; 3rd tergite with large central triangular region of dull black pollen, and with short, appressed and black pile, except slightly longer baso-laterally and white on basolateral ⅓. Fourth tergite sub-quadrate, slightly longer than wide, with mostly dull black pollen, and with short, appressed and black pile. Fifth tergite rectangular and wide, and with dull black pollen restricted to 3 median vittae; remaining characteristics as on 4th. First sternite with long white pile. Genitalia: Not dissected.

Female: Female unknown.

Length. 11.5mm; wing 9mm.

Distribution. Mexico (Veracruz).

Material examined. MEXICO. Vera Cruz, Jalapa, 4400 ft., Type 6375 Baccha tristis Hull [red label], Baccha tristis n. sp. Type Hull [identification label], 12 Oct 1906, P.P. Calvert (1 ♂, ANSP).

Comments. The only other species in Pelecinobaccha with dense black pile on the thorax are P. pilipes and P. pilinigridensis . Neither of these species has the frontal triangle pollinosity or the confluent antennal insertions of the holotype of B. tristis . The holotype has its head glued to the thorax raising the possibility that it is actually a composite.