Toxomerus difficilis (Curran)

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 : 28-29

Toxomerus difficilis (Curran)

( Figs. 24, 89, 90, 91)

Mesogramma difficilis Curran, 1930: 6 (descr.); 1934: 399 (key); Hull, 1943b: 28 (illustration).

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

Toxomerus difficilis Thompson et al., 1976: 49 (cat. & n. comb.); Thompson, 1981: 85 (key).

Male. Head: face 1/2 as long as eye width, yellow, shiny except sparsely white pollinose and pilose laterally; gena black; frontal triangle yellow with a little brown macula next to lunule, black pilose; vertical triangle black, white and 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; proepisternum black, white pollinose; proepimeron yellow; scutum black except broadly yellow laterally, bronze pollinose except for bluish-white pollinose medial vitta, yellow pilose; scutellum brown with yellow margins, sometimes yellow, 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; anterior anepimeron yellow to brownish; dorsomedial anepimeron yellow; posterior 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 yellow posterodorsally; methatoracic pleuron yellow; metasternum yellow to brown; halter yellow. 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 2/3; metafemur yellow except for black annulus on apical 1/3, yellow and black pilose; pro- and mesotibiae yellow, yellow pilose, mesotibia black pilose on basal 2/3; metatibia usually black on basal 2/3 and yellow on apical 1/3, black pilose; pro- and mesotarsi yellow to brownish, yellow pilose; metatarsus brown to black, black pilose. Wing: hyaline, 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 usually black except yellow anteriorly and laterally; 2 nd tergum yellow except narrowly black anteriorly or black with medial yellow fascia and medial yellow vitta; 3 rd to 4 th terga all yellow or black with yellow fascia on anterior 1/2 with two medial black macula; 5 th tergum yellow except black macula medially and brownish fascia posteriorly ( Fig. 24). Male genitalia: surstylus with a median pointed projection at apex, with scattered short setae; postanal process 2/3 as long as surstylus; aedeagus enlarged, with slender projection dorsally; superior lobe somewhat rectangular with setae on anterior margin, and hairs on posterior half.

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

Female genitalia: 9 th tergum with a semicircle black macula with a spur medially; epiproct slender; cercus slender; hypoproct somewhat triangular; 9 th sternum as in Fig. 90; three oval spermatecae similar in size ( Figs. 89–91).

Length. Body 6.0–6.5 mm, wing 5.5 mm.

Type material examined. Holotype. PUERTO RICO. Coamo Springs : Mesogramma difficilis , ♂, 5–7/ VI/1915 ( AMNH) . Allotype. PUERTO RICO. Coamo Springs : Mesogramma difficilis , ♀, 17–19/VII/1914 ( AMNH) .

Other material examined. PUERTO RICO. Cidra: 2 ♂ & 4 ♀, 12/IV/1967; Esperanza : ♂ & 2 ♀, J. W. Boyes ( CNC) . BRAZIL. Rio de Janeiro: Friburgo , ♂, II/1932, M. L. ( MNRJ) . São Paulo: Mogi Guacu, Campininha , 11 ♂ & 4 ♀, 23–28/X/1970, J. W. Boyes ( CNC) ; Ilha Seca , ♂, 19–26/II/1940 ( CNC) ; S. P., ♀, 27/XII/1972, B. V. Peterson ( CNC) ; Campos do Jordão , ♂, III/1945, Wygodzinsky ( MNRJ) . Santa Catarina: Nova Teutônia , ♂, ♀, I/1965, XI/1971, F. Plaumann ( USNM) ; 6♂, ♀, 14/IV/1960, F. 29/III/1965, XI/1969, XII/1969, F. Plaumann ( CNC) ; ♀, V/1970, F. Plaumann ( MZSP) .

Geographical record. West Indies, Central America to Southern Brazil.