Toxomerus croesus (Hull)

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 : 19-20

Toxomerus croesus (Hull)

( Figs. 5, 11, 86, 87, 88)

Mesogramma croesus Hull, 1940a: 248 (descr.).

Mesograpta croesus Fluke, 1956: 221 (cat.).

Toxomerus croesus Thompson et al., 1976: 49 (cat. & n.comb.).

Male. Head: face 1/3 as long as eye width, yellow, shiny except sparsely white pollinose and pilose laterally; gena brown; frontal triangle yellow, white pilose; vertical triangle black, white pollinose, black pilose; occiput black, silver pollinose, with thick white pile, with a short row of brownish pile superiorly; antenna yellow, black pilose, arista brown.

Thorax: postpronotum yellow; proepisternum black, bronze pollinose; proepimeron black; scutum black except broadly yellow laterally, bronze pollinose except for bluish-white pollinose medial vitta, yellow and black pilose; scutellum brown with yellow margins, yellow and black pilose; anterior anepisternum black, short and sparsely yellow pilose; posterior anepisternum black on anterior 1/2, yellow pilose dorsally, posterior ½ yellow, yellow pilose; katepisternum black except 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; metasternum yellow; halter yellow ( Fig. 5). Legs: pro- and mesocoxae black on basal 2/3, yellow apically, yellow pilose; metacoxa yellow, yellow pilose; trochanters yellow, yellow pilose; pro- and mesofemora yellow, yellow pilose, mesofemur black pilose on apical 1/3; metafemur yellow except for black annulus on apical 1/3, yellow and black pilose; pro- and mesotibiae yellow, yellow pilose; metatibia black, yellow on basal and apical extremities or black on basal 2/ 3 and yellow on apical 1/3, yellow and black pilose; pro- and mesotarsi yellow, yellow pilose; metatarsus brown to black, yellow and black pilose. Wing: 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 as broad as cell C, not microtrichose ( Fig. 11).

Abdomen: terga yellow and black pilose; 1 st tergum yellow except narrowly black posteriorly; 2 nd tergum black with medial yellow fascia and brownish-orange fascia anteriorly and posteriorly; 3 rd to 4 th terga black with sub-lateral arcuate yellow vitta, medial yellow vitta extended posteriorly and latero-anetriorly yellow macula; 5 th tergum yellow with three black macula. Male genitalia: surstylus little convex apically in lateral view, with scattered short setae; postanal process 1/2 as long as surstylus; aedeagus enlarged, slightly proeminent dorsally; superior lobe somewhat trapezoid with short dorsal extension, forked distad, with scattered hairs, longer along anteroventral margin, with small lobe posteriorly with hairs.

Female. Similar to male except for the frons black, white pollinose, black pilose. Anterior anepisternum bare. Female genitalia: 9 th tergum with somewhat rectangular black macula concave anteriorly and convex posteriorly; epiproct as kidney form; cercus broad somewhat triangular; hypoproct as a triangular arch; 9 th sternum as in Fig. 87; three biconvex spermatecae similar in size ( Figs. 85–88).

Length. Body 9.0 mm, wing 8.0 mm.

Type material examined. Holotype. BRAZIL. São Paulo: Osasco , Mesogramma croesus , male, 1–8/IV/ 1939, J. Lane ( CNC).

Other material examined. BRAZIL. Minas Gerais: Varginha , 5 ♂ & 9 ♀, II/1972, M. Alvarenga ( MNRJ) . Rio de Janeiro: Jacarepaguá , ♂, XII/1969, M. Alvarenga ( MNRJ) ; ♀, III/1970, M. Alvarenga ( MNRJ) ; Alto da Boa Vista , ♀, 13/I/1951, Dalcy & S. Lopes ( MNRJ) . São Paulo: Tamoio , ♂, 3/II/1944, Barreto ( CNC) ; Santa Catarina: Nova Teutônia , 2♀, IX/1964, XII/1964, F. Plaumann ( USNM) ; ♂, XI/1964, F. Plaumann ( CNC) .

Geographical record. Southeastern to southern Brazil.