Setacera jamesi Mathis 1982

Setacera jamesi

DESCRIPTION.—Large shore flies, length 5.06 to 5.67 mm; generally brown to olivaceous brown or gray, becoming grayer and duller ventrally.

Head (Figure 91): Head width-to-height ratio averaging 1 : 0.67; frons width-to-length ratio averaging 1 : 0.47; mesofrons and fronto-orbits deeply blue to slightly greenish blue; dorsum of interfoveal carina mostly greenish to slightly bluish green; arista with longest dorsally branching rays short, at most slightly longer than aristal width at base; dorsal surface of face broadly explanate (best seen in dorsal view), dorsum of interfoveal carina and antennal foveae almost on same horizontal plane; dorsal surface of face shorter than anterior surface; facial angle at about 90°; angle formed by anterior surface and oral margin obtuse in lateral view, anterior surface receding to oral margin; eye height-to-width ratio averaging 1 : 1.14; eye-to-cheek ratio averaging 1 : 0.57.

Thorax: Supraspiracular convexity evenly convex; forecoxa of male with longer, more numerous setae anteromedially and posteriorly, to a lesser extent on midcoxa; midtibia of male with dense patch of slightly longer setae posteroapically; costal vein ratio averaging 1 : 0.26; M1+2 vein ratio averaging 1 : 0.88.

Abdomen: Male 5th tergal ratio averaging 1 : 0.89; 5th tergum of male lacking anteroventral projection. Male terminalia (Figures 92–94): surstyli in posterior view (Figure 94) subtriangular, broadly fused basally lateral margins narrowing to ventral apex at right angles to each other, lacking distinct lateral projections, bluntly rounded and curved anteriorly in lateral view; gonite with ventrolateral prong, curved medially, acutely pointed, 2 long, posterior setae (longer than gonal prong), broadly attached to aedeagus dorsally; aedeagus folded back on itself, broadly rounded apically; hypandrium pocket shaped, lateral margin overlaid, with 2 medial, cruciate, well sclerotized prongs. Female terminalia (Figures 95–98): 7th tergum complete; 8th sternite subtriangular, anterior margin rounded, posterior margin shallowly concave, posteroventral corner slightly projecting; only slightly higher than wide; 8th sternites about 4 times longer than wide; 9th sternites almost twice as long as high; cercus higher than long, with subquadrate posterodorsal projection; female ventral receptacle (Figure 96) with lateral margin of operculum slightly flared ventrally, cervix comparatively shorter than other species, lacking distinct indentation at juncture of cervix with corpus.

TYPE MATERIAL.—The male holotype is labeled: “Orick [Humboldt Co.] CAL[ifornia] 18 Sep. [19]34 ALMelander/HOLOTYPE Setacera jamesi Mathis [handwritten, red].” Allotype female and one male paratype are labeled with the same label data as the holotype. Other paratypes are as follows. Oregon: Lincoln Co., Boiler Bay, 9 Mar 1930, J. Wilcox (1; USNM Washington: Pacific Co., Ocean Park, 18 Aug 1950, M. T. James (3, 2; USNM, WSU The holotype specimen is in excellent condition (directly pinned) and is in the National Museum of Natural History, Smithsonian Institution, USNM 76885.

DISTRIBUTION (Figure 90—Coast of western North America between 41° and 48° north latitude.

NATURAL HISTORY.—The immatures and ecology of the species are presently unknown. The apparent association of this species with coastal aquatic systems may indicate a tolerance toward salty environs and, perhaps, a preference for it.

ETYMOLOGY.—The specific epithet jamesi honors Dr. M. T. James, Washington State University, for his continuing contribution to dipterology