Toxomerus laenas (Walker)

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 : 39-40

Toxomerus laenas (Walker)

( Figs. 30, 56, 57, 58, 110, 111, 112)

Syrphus barbulus Walker, 1852: 238 (descr.); Kertész, 1910: 107 (cat.).

Syrphus laenas Walker, 1852: 241 (descr.); Kertész, 1910: 117 (cat.).

Mesogramma nitidiventris Curran, 1930: 9 (descr.); 1934: 398 (key).

Mesogramma vitrea Hull, 1941b: 45 (descr.).

Mesogramma barbula Hull, 1943a: 10 (n. comb.).

Mesogramma laenas Hull, 1943a: 10 (n. comb); 1943b: 16, 40 (key and ill.).

Mesograpta barbula Fluke, 1956: 218 (cat.).

Mesograpta laena Fluke, 1956: 224 (cat.).

Mesograpta nitidiventris Fluke, 1956: 226 (cat.).

Mesograpta vitrea Fluke, 1956: 233 (cat.).

Toxomerus barbulus Thompson et al., 1976: 48 (cat. & n.comb.), syn. nov.

Toxomerus laenus Thompson et al., 1976: 51 (cat. & n. comb.).

Toxomerus nitidiventris Thompson et al., 1976: 53 (cat. & n.comb.), syn. nov.

Toxomerus vitreus Thompson et al., 1976: 56 (cat.& n. comb.), syn. nov.

Male. Head: face 1/3 as long as eye width, yellow, sometimes with black medial vitta, shiny except sparsely white pollinose and pilose laterally; gena black; frontal triangle yellow, white 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 brownish to black; proepisternum black, white pollinose; proepimeron black; scutum black, bronze pollinose except for two lateral and one medial bluish-white pollinose vitta, white pilose; scutellum black, white pilose; anterior anepisternum black, long yellow pilose; posterior anepisternum black anterior 2/3, yellow pilose dorsally, and yellow posterior 1/3, 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; methatoracic pleuron black; metasternum black; halter yellow. Legs: coxae black, yellow pilose; trochanters yellow to brownish, yellowish pilose; femora black, yellow on basal and apical extremities, yellow and black pilose; tibiae brown, yellow and black pilose; protibia sometimes yellow with black annulus on medial 1/3; tarsi brown, brown pilose; mesotarsus black pilose ventrally. 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 as broad as cell BM appically, microtrichose.

Abdomen: terga yellow and black pilose; 1 st tergum all black; 2 nd tergum all black; 3 rd to 5 th terga all black or 3 rd tergum black and 4 th and 5 th terga orange ( Fig. 30). Male genitalia: surstylus almost as long as epandrium, with scattered short setae; postanal process little distinct; aedeagus slender dorsally; superior lobe somewhat triangular with setae medio-ventrally and scattered hairs ( Figs. 56–58).

Female. Similar to male except for the frons black, white pollinose, yellow pilose. Anterior anepisternum bare.

Female genitalia: 9 th tergum with not distinct black macula; cercus slender; hypoproct somewhat oval; 9 th sternum as Fig. 111; three rounded spermatecae similar in size ( Figs. 110–112).

Length. Body 6.0–7.0 mm, wing 5.0–5.5 mm.

Discussion. The synonymies were based on the examination of the male holotype of Mesogramma nitidiventris , male holotype of Mesogramma vitrea , male holotype of Syrphus laenas and female syntype of Syrphus barbulus . The postpronotum black is an external character that helps to identify this species. Toxomerus barbulus and Toxomerus laenas were described at the same paper ( Walker 1852). T. laenas was choosed as senior synonym, based on the reason the description belongs a male specimen.

Type material examined. Holotype. BRAZIL. Syrphus laenas , male ( BMNH).

Other material examined. PARAGUAY. Villarrica : 2 ♂, VIII/1937, F. Schade ( USNM) ; ♀, IX/1937, F. Schade ( USNM) . BRAZIL. Goiás: Formosa, 2 ♀, 25/IV/1972, L. Knutson ( USNM) . Brasília: National Park , 2 ♀, 23/IV/1972, L. Knutson ( USNM) ; Distrito Federal , ♂ & ♀, 24/IV/1972, L. Knutson ( USNM) ; ♂ & ♀, 4–5/X/1974, L. Knutson ( USNM) . Minas Gerais: Viçosa , ♂, 13/X – 1/XI/1985, T. J. Henry & S. P. Fiuza F. ( USNM) ; Lagoa Santa , 2 ♂, 18/I/1977, L. Knutson ( USNM) . São Paulo: Cantaneira , ♂, VII-45, J. Lane ( MZSP) ; Boracea , ♀, VI-1947, Rabello ( MZSP) , ♀, IX-1947, J. Lane; Severínia , ♂, XII-1940, A. G. Silva ; Salesópolis , 5 ♂ & 2 ♀, 14–19/X/1970, J. W. Boyes & J. H. Guimarães ( CNC) ; Campininha , 3 ♂ & ♀, 23–28/ X/1970, J. W. Boyes ( CNC) . Rio Claro , ♀, 14/I/1977, L. Knutson ( USNM) ; Piracicaba , ♂, 11/I/1977, L. Knutson ( USNM) ; Bocaina , 3 ♂, V/1951, III/1954, Dalcy & R. Barros ( MNRJ) ; Cajurá , ♂, X/1954, M. P. Barreto ( MZSP) . Paraná: Curitiba , ♂ & ♀, J. W. Boyes ( CNC) . Foz do Iguaçu , ♀, 19/VII/1961, N. L. H. Krauss ( USNM) . Santa Catarina: Nova Teutônia , 4♂, 2 ♀, 23/III/1960, I/1970, F. Plaumann ( CNC) ; ♂, V/ 1970, F. Plaumann ( USNM) ; 13 ♂ & 3 ♀, V/1970, F. Plaumann ( MZSP) .

Geographical record. South America, southern Brazil and Paraguay.