Ephydra pacifica

Mathis, Wayne N. & Marinoni, Luciane, 2016, Revision of Ephydrini Zetterstedt (Diptera: Ephydridae) from the Americas south of the United States, Zootaxa 4116 (1), pp. 1-110 : 99-100

The pacifica Group

Species Included: Setacera durani Cresson ; S. pilicornis (Coquillett) ; and S. trichoscelis Mathis.

Diagnosis. Specimens of the pacifica group may be distinguished by the following characters:

Head: Antennal grooves sparsely microtomentose, subshiny, nearly concolorous with dorsum of interfoveal hump and with similar metallic luster; vertico-orbits with velvety microtomentose band very narrow, inconspicuous.

Thorax: Presutural supra-alar seta well developed, subequal or slightly weaker than posterior notopleural seta, distance between it and presutural seta slightly less than that between notopleural setae; fore- and midtibiae mostly dark and concolorous with femora, at most with tibial-femoral articulation pale.

Abdomen: Tergite 5 of male longer than either tergites 3 or 4, narrowly to bluntly rounded, width at apex much less than length; male sternites 3 and 4 usually with dense patch of stout setae toward posterior margin, secondarily reduced in some species ( S. needhami and S. trichoscelis ). Male terminalia as follows: epandrium subtriangular in posterior view, much narrower dorsally than ventrally, dorsum narrowly rounded, becoming gradually broader, truncate ventrally, lacking medial sulcus ( S. pacifica with superficially indication); cerci almost as wide as high in lateral view, with anteroposterior orientation; surstyli broadly fused basally (best seen in posterior view), usually with lateral and sometimes with medial projections (shape diagnostic at species level), apically curved anteriorly in lateral view; gonite with prong-like projections, conformation and arrangement differing with species; aedeagus bluntly rounded apically; hypandrium with 1–2 projections, at least partially and usually mostly well sclerotized. Female terminalia as follows: tergite 7 variable; tergite 8 comparatively short, almost as wide as high in some species, shape of dorsum in lateral view varying with species; 8th sternites elongate, 4 or more times longer than wide; sternite 9 vertically oriented, projected posteriorly, well sclerotized, forming 2 conical projections; sternite 9 with l setae borne at apex of sternite 9 projections, 2 large setae on each, these approximate, often difficult to distinguish; female ventral receptacle with operculum as high as wide, subtrapezoidal to dome-shaped in lateral view, extended process with cervix as long as corpus, more or less parallel sided, juncture of cervix and corpus indicated on medial surface of curvature by small, lateral indentation, forming budlike projection in lateral view, curvature of corpus wide, open.

Distribution. New World. Except for S. trichoscelis , this species group is North American, mostly occurring west of the 100 meridian. An obvious exception is S. pilicornis , which occurs in southeastern United States and in Mexico.