Stilobezzia albicoxa Lane & Forattini

Stilobezzia (Stilobezzi a) albicoxa Lane & Forattini, 1956: 210 (female, male, Panama); Lane & Forattini, 1961: 87 (in key); Das Gupta & Wirth, 1968: 114, 138 (placed in subviridis group, and in World checklist); Borkent & Spinelli, 2000: 53 (in New World catalog south of the USA; distribution); Borkent & Spinelli, 2007: 86 (in Neotropical catalog; distribution); Borkent & Dominiak, 2020: 178 (World catalog).

Stilobezzia (Stilobezzia) dureti Lane & Forattini, 1958: 210 (male, Brazil), syn. nov.

Diagnostic characters. Wing length 1.27 – 1.64 mm; thorax and abdomen dark and yellow colored; legs yellowish. Male gonocoxite with two inner sclerotized projections, the basal one straight, almost touching the one on the opposite side; parameres L-shaped. Female flagellomeres with fine setae; flagellomeres 2 – 8 blackish brown with stout setae, 9 – 13 pale brown; two rounded spermathecae.

Male. Head (Fig. 1.B) brown; antenna with flagellomeres pale brown; plume dark brown, dense between flagellomeres 1 – 10; antennal ratio 1.04 (n= 1). Palpus pale brown; third segment slender, slightly shorter than fifth; palpal ratio 3.66 (n= 1). Thorax (Fig. 1.B). Scutum dark brown, humeral pits paler; scutellum dark brown laterally, pale yellowish medially with 4 stout setae, 2 submedial, 2 lateral; postscutellum dark brown; pleura dark brown except white margins of anepisternum. Legs: golden yellowish except tarsomeres paler, hind coxa whitish, mid coxa, posterior coxa dark brown; hind tibial comb with 8 spines; fore leg tarsal ratio 2.06 (n= 1); mid leg tarsal ratio 2.75 (n= 1); hind leg tarsal ratio 2.46 (n=1). Wing membrane hyaline (Fig. 1.C); second radial cell 5 times longer than first; cubital fork distal to level of base of r-m crossvein; wing length 1.27 mm (n= 1); width 0.40 mm (n= 1); costal ratio 0.69 (n= 1). Halter stem pale, knob dark brown. Abdomen tergite 1 dark brown with concave narrow, anterior pale spot, tergites 2 – 6 dark brown, 7 – 9 pale brown; sternites, pleural membrane pale (Fig. 1.B). Genitalia (Figs. 1.E–F): tergite 9 extending slightly beyond apex of gonocoxite, distal margin rounded; cerci conspicuous; sternite 9 3.6 times wider than long; posterior margin straight. Gonocoxite stout 2.5 times longer than greatest width, inner margin with 2 sclerotized projections, basal projection straight, almost touching the one on the opposite side, distal projection smaller, pointed, directed posteriorly; gonostylus curved, slightly shorter than gonocoxite with rounded apex. Parameres separated, subparallel, each one L-shaped with basal arm oblique, distal arm stout, more sclerotized. Aedeagus represented by two sinuous sclerites, each one with a basal arm slender, pointed, distal portion with a short, hook- shaped projection.

Female. Similar to male, with the following notable gender differences. Head (Fig. 1.A) flagellomere 1 yellowish basally, dark brown distally; flagellomeres 2 – 8 blackish brown with stout setae, flagellomeres 9 – 13 pale brown with fine setae; antennal ratio 1.40 – 1.53 (1.46, n= 2). Palpal ratio 3.85 – 342 (3.63, n= 2). Mandible with 7 – 8 teeth. Thorax (Fig. 1.A). Scutum yellowish with anteromarginal dark brown areas; postscutellum yellowish anteromedially; tarsomere 5 of all legs with 1 pair of batonnets; fore leg tarsal ratio 2 – 07 – 2.14 (2.10, n= 2); mid leg tarsal ratio 2.62 – 2.58 (2.60, n= 2); hind leg tarsal ratio 2.26 – 2.34 (2.30, n= 2); claws slightly shorter than tarsomere 5; claw of mid leg larger (Fig. 1.D). Wing length 1.62 – 167 mm (1.64, n= 2); width 0.55 mm (n= 2); costal ratio 0.72 – 0.76 (0.74, n= 2). Abdomen sternite 8 not distinguishable, only the posteromedian excavation V shaped; sternite 9 not distinguishable; sternite 10 with 3 – 4 pairs of setae; cercus rounded; two rounded, subequal spermathecae with short slender necks, measuring 70–80 µm (75, n= 2) by 50–110 µm (90 n= 2) and 70–80 µm (075, n= 2) by 80–90 µm (85, n= 2).

Material examined. Types. Stilobezzia albicoxa, holotype female: PANAMA: Prov. Panama, Pto. Farallon, XI- 1952; allotype male: PANAMA: Prov. Darien, Carachin, II-1953, F. S. Blanton. Stilobezzia dureti, holotype male: State of Sãn Pablo, Ribeirão Preto, X-1954, J. P. Duret Brazil ( Faculdade de Saúde Pública, Universidade de São Paulo, Brazil) .

Other specimens. Brazil, Amazonas, Manaus, Parque Estadual Sumauma, 03°05’50.90” S, 60°02’03.96” W, Malaise trap, 22 – 26-II-2016, I.M. Silva, R. L. Ferreira-Keppler, 1 male; Suspended trap, 11 – 15-IV-2016, I.M. Silva, R.L. Ferreira-Keppler, 1 female . Brazil, Amazonas, Manaus, Instituto Nacional de Pesquisa da Amazônia - Campus II, 03°05’40.42” S, 59°59’21.31” W, Malaise trap, 11 – 15-IV-2016, I.M. Silva, R. L. Ferreira-Keppler, 1 female. (Invertebrate Collection of the Instituto Nacional de Pesquisas da Amazônia, Brazil) .

Distribution. Panama, Brazil (São Paulo); currently reported for the first time from Amazonas State.

Taxonomic remarks. Lane and Forattini (1956) originally described the abdomen of S. albicoxa as “ with tergite 1 broadly yellowish or greenish on a quadrate spot in the middle, sides blackish brown, other tergites shining black”, however, we examined the type specimens and this structure is not as described above. Instead the tergite 1 is dark brown with an anterior concave and narrow pale spot.

The Brazilian species S. dureti was described by Lane & Forattini (1958) from a single male specimen. After analyzing the original description and examining the types of S. dureti and S. albicoxa we concluded that the first mentioned species is a junior synonym of S. albicoxa . The most conspicuous diagnostic characters of both species are shared: coloration of thorax and abdomen, shape of parameres, aedeagus and gonostylus (see Figs. 1 E – G).