Toxomerus basalis (Walker) Borges & Couri, 2009

Borges, Zuleica M. & Couri, Marcia S., 2009, Revision of Toxomerus Macquart, 1855 (Diptera: Syrphidae) from Brazil with synonymic notes, identification key to the species and description of three new species 2179, Zootaxa 2179, pp. 1-72 : 16-19

Toxomerus basalis (Walker) n. comb.

( Figs. 4, 19, 22, 23, 41, 42, 43, 83, 84, 85)

Syrphus basalis Walker, 1837: 345 (descr.); Kertész, 1910: 107 (cat.); Fluke, 1957: 155 (cat.); Thompson et al., 1976: 39 (cat.).

Syrphus portius Walker, 1852: 239 (descr.); Kertész, 1910: 124 (cat.).

Syrphus basilaris Williston, 1886: 328 (cat.) [misspelling].

Mesogramma portia Hull, 1943b: 12 , 17 (key & illus.).

Mesogramma rhea Hull, 1949c: 228 (descr.).

Mesogramma harlequina Hull, 1951b: 69 (descr.).

Mesograpta portius Fluke, 1956: 228 (cat.).

Mesograpta harlequina Fluke, 1956: 223 (cat.).

Mesograpta rhea Fluke, 1956: 229 (cat.).

Toxomerus portius Thompson et al., 1976: 54 (cat. & n. comb.); Thompson, 1981: 100 (note), syn. nov.

Toxomerus rhea Thompson et al., 1976: 54 (cat. & n. comb.), syn. nov.

Toxomerus harlequinus Thompson et al., 1976: 50 (cat, & n.comb.), syn. nov.

Male. Head: face 1/2 as long as eye width, yellow to brownish, shiny except sparsely white pollinose and pilose laterally; gena black; frontal triangle yellow, black pilose; vertical triangle black, bronze pollinose, black pilose; occiput black, silver pollinose, with thick white pile, with a short row of brownish pile superiorly; antenna yellow to brownish, black pilose, arista brown.

Thorax: postpronotum yellow to brownish; proepisternum black, white to bronze pollinose; proepimeron brown; scutum black except broadly yellow to brownish laterally, bronze pollinose except for bluish-white pollinose medial vitta, yellow pilose; scutellum black with yellow to brownish margins, yellow pilose with black piles on posterior margin or black pilose; anterior anepisternum black, short and sparsely yellow pilose; posterior anepisternum black on anterior half, yellow pilose dorsally, and yellow on posterior 1/2, yellow pilose; katepisternum black except on dorsal 1/3 yellow, dull, yellow pilose; anepimeron black; plumula yellow, calypter yellowish with yellowish fringe except brown fringe on dorsal lobe; posterior mesothoracic pleuron (katepimeron, meron, katatergum, anatergum and postscutellum) black, anatergum brownish posterodorsally; methatoracic pleuron yellow to brownish; metasternum brown; halter yellow ( Fig. 4). Legs: pro- and mesocoxae black on basal 2/3, yellow to brownish apically, yellow pilose; metacoxa yellow to brownish, yellow pilose; trochanters yellow, yellow pilose; femora black, yellow on basal and apical extremity, yellow and black pilose; pro- and mesotibiae all yellow or with black annulus on medial 1/3, yellow and black pilose; metatibia black, yellow on basal and apical extremities, black pilose; protarsus brown, yellow ventrally, brown pilose; meso- and metatarsi black, black pilose ( Fig. 19). Wing: hyaline to brownish, extensively microtrichose, bare only: on basal 1/2 or less of cell C, basal 1/5 of cell R1, basal 2/3 or less of cell R and basal 3/4 or less of cell BM; alula broader than cell BM appically, microtrichose.

Abdomen: terga yellow and black pilose; 1 st tergum black except narrowly yellow anteriorly; 2 nd tergum all black or yellow only lateral 1/3; 3 rd to 5 th terga black with yellow macula latero-anteriorly ( Figs. 22, 23). Male genitalia: surstylus with pointed apex, with scattered short setae; postanal process not so distinct; aedeagus all enlarged; superior lobe somewhat rectangular, forked dorsally, with erect setae in distad ventral margin and scattered hairs ( Figs.41–43).

Female. Similar to male except for the frons black, bronze pollinose, black pilose. Anterior anepisternum bare. Female genitalia: 9 th tergum with extend tranversal black macula medially; epiproct somewhat elliptical; cercus slender; hypoproct somewhat triangular; 9 th sternum as in Fig. 84; three elliptical spermatecae, one of them smaller ( Figs. 83–85)

Length. Body 5.5–6.0 mm, wing 5.5–6.0 mm.

Discussion. The male holotype of T. portius , the female holotype of Mesogramma harlequina and three male and one female cotypes of Mesogramma rhea were examined dissected and compared with the holotype of Syrphus basalis .

Type material examined. Holotype. BRAZIL. Syrphus basalis , male ( BMNH) . Other material examined. BRAZIL. Rio de Janeiro: ♂, III/1952, A. G. da Silvas ( MNRJ) . São Paulo:

Bocaina, ♀, V/1951, D. Albuquerque ( MNRJ); ♂, III/1954 , Dalcy and R. Barros ( MNRJ); XI/1970 , M.

Alvarenga ( MNRJ). Santa Catarina: Nova Teutônia , 4 ♂, 2♀, VI/1964, F. X/1964, VII/1965, V/1970, XI /

1971, F. Plaumann ( USNM); 5♂ & 2 ♀, IX/1964, F. X/1964, F.F.F. XI/1969, F. Plaumann ( CNC). Geographical record. Southeastern Brazil .