Hydrellia xanthocera Cresson, 1938

Júnior, Francisco De Assis Rodrigues, Mathis, Wayne Nielsen & Couri, Márcia Souto, 2014, Hydrellia Robineau-Desvoidy (Diptera: Ephydridae) from Brazil with an emphasis on the faunas from the states of Parana and Rio de Janeiro, Zootaxa 3753 (6), pp. 501-541 : 522-524

Hydrellia xanthocera Cresson, 1938

(Figs.: 4.6, 16.1–16.7 and 17)

Hydrellia xanthocera Cresson 1938: 33 (description of male and female). Holotype female, MNRJ. Type-locality: Brazil, Rio de Janeiro, Rio de Janeiro (22°54.2'S, 43°12.6'W *); Cresson 1947: 37 (review, Neotropical species); Wirth 1968: 13 (Neotropical catalog); Mathis & Zatwarnicki 1995: 94 (world catalog).

Diagnosis. Body length of male 1.71–1.88 mm, female 1.85–1.99 mm; ocellar setae absent; frons densely microtomentose; frontal vitta velvety reddish brown; fronto-orbital plate darker, velvety brown to black; antennae mostly yellow, except for dorsal margin of pedicel and first flagellomere sometimes darkened (fig. 4.6); ocellar triangle, postpronotum, anepisternum and anepimeron densely silvery white microtomentose (fig. 4.6); notopleuron and extended area of supra-alar, katepisternum and scutellum densely microtomentose, appearing velvety reddish brown (fig. 4.6); 2 scutellar setae, mid pair absent; foretibia yellow; tarsi mostly yellow except for dark brown apical tarsomere; sternite 5 deeply concave and congruent with distiphallus (figs. 16.1 and 16.2); surstylus in ventral view broader than high, shallowly concave on anterior margin (figs. 16.1 and 16.7).

Description. Head: frons broader than high, densely microtomentose; frontal vitta velvety reddish brown; fronto-orbital plate darker, velvety brown to black; ocellar triangle silvery white microtomentose; ocellar setae absent; both proclinate and reclinate fronto-orbital setae present, with a third smaller proclinate setula between them; antennae mostly yellow, except for dorsal margin of pedicel and first flagellomere sometimes darkened (fig. 4.6); pedicel usually with 1 well-developed seta on dorsal margin and 2 well-developed hair like setulae on ventral margin; 5–8 aristal rays; face narrow, yellow, silver microtomentose; lunule usually silver; parafacial narrow, concolorous with face; antennal grooves distinct; face in lateral view nearly vertical but with low, ventromedial carina; primary facial setae 3–4; genal groove, gena and postgena reddish brown silvery white microtomentose, occiput velvety reddish brown; 1 genal seta; maxillary palpus yellow; epistomal ratio: 1.48–1.76; mesofacial ratio: 3.08–3.18; vertex ratio: 5.41–6.77; eye-to-gena ratio: 5.15–5.89; head ratio: 1.14–1.15.

Thorax: well-developed dorsocentral setae 0+1; 2 scutellar setae, mid pair absent; 1 postpronotal seta; 1 mesokatepisternal seta; mesonotum reddish brown sparsely silvery white microtomentose, subshiny to shiny; postpronotum, anepisternum, and anepimeron reddish brown densely silvery white microtomentose (fig. 4.6); notopleuron and extended area of supra-alar, katepisternum and scutellum densely microtomentose, appearing velvety reddish brown (fig. 4.6). Wings: length 1.80–2.21 mm; hyaline with pale brown venation; halter yellow; costal sections indices: II/I: 2.35–2.85; III/IV: 3.14–3.28; V/IV: 3.27–3.45; vein M ratio: 3.82–4.77. Legs: coxae, trochanters and femora reddish brown, sparsely silvery white microtomentose; ctenidial setae along anteroventral margin of forefemur almost always absent, present in holotype and other two specimens, almost imperceptible; fore tibiae yellow; mid and hind tibiae usually concolorous with femora except for apical yellow margin; tarsi mostly yellow except for dark brown apical tarsomere.

Abdomen: dark reddish brown to black, subshiny to shiny; sparsely silvery white microtomentose. Male terminalia: sternite 5 deeply concave and congruent with distiphallus (figs. 16.1 and 16.2); surstylus in ventral view broader than high, shallowly concave on anterior margin (figs. 16.1 and 16.7); postgonite bent anterolaterally (figs. 16.1 and 16.2); aedeagus in ventral view fusiform, distiphallus small (fig. 16.3); phallapodeme in ventral view truncate at the attachment with postsurstylus, bent dorsally, bifurcated at the attachment with hypandrium (fig. 16.5); epandrium narrow (fig. 16.1). Female terminalia: third to tergite 5s subequal in size; tergites 6–8 very short, retracted within tergite 5; hypoproct oblong; sternites subequal, roundly quadrate, microsetulose; cerci in lateral view ovoid; ventral receptacle with a cap cupuliform as broad as high.

Material examined. Brazil. Rio de Janeiro (22°54.2'S, 43°12.6'W), IX.1934, H. Souza Lopes (1 female; holotype; MNRJ). Rio de Janeiro, Grajaú (22°55'12''S, 43°15'52''W *), 13.VIII–27.VIII.1939, H. Souza Lopes (9 male, 4 female; CEIOC; 2 abdomen destroyed). Rio de Janeiro, Jacarepaguá (22°57'34''S, 43°22'8''W *), 5.XI.1939, H. Souza Lopes (2 male; CEIOC).

Distribution. Neotropical: Brazil (Rio de Janeiro) and Panama.

Notes. Hydrellia xanthocera Cresson belongs to the formosa species group, distinguished by the absence of the ocellar seta. This species is similar to H. bocaiuvensis sp. nov., but can be distinguished by the body coloration, the coloration of flagellomere 1 and by the number of scutellar setae. Illustrations of the male terminalia and the first photograph of the holotype of this species are provided for the first time.