(Fig. 10 A–C)
Locus typicus: USA, Arizona, Pimo County, Tucson Mts. 16 km W Tucson, 30.24°N, 111.13°W, Sonora desert. Holotype: Male, 30.iv.–16.v.1995, leg. S. Prchal, Malaise trap (PWMP).
Description. Male. Head. Eye bridge 3 facets wide. 4th flagellomere with l/w-index 2.2, haired whitish, as long as basal node wide. Palpus 3-segmented, short; basal segment with deepened sensory pit and 2–3 bristles. Thorax. Brown; scutum haired whitish. Wings pale; R1: R = 0.5; c short, = 1/3 w; y = x, with 1–2 bristles; posterior veins bare. Haltere short, brownish. Legs yellowish; tibial organ of fore tibia small, with 4–5 bristles on a small lobe; spurs of middle tibia vary, one is long, the other strongly reduced; hind tibia with unequal long spurs; claws toothless. Abdomen. Brown, haired sparsely, whitish. Hypopygium brown; ventral base closed; gonocoxites longer than gonostylus, haired short and sparsely. Gonostylus concaved on inner side, without apical tooth; with 3 subapical spines and longer apical bristles. Tegmen trapezoid. Body size: 2 mm.
Comments. The species belongs to the armata group of the subgenus Xenopygina Frey. It is characterized by curved gonostylus, concaved on inner side and a slightly bilobated apex with three dark spines. It is similar to Sc. praealawae (for differences see there).
Distribution. USA (Arizona).
* Alawae = pea, Algonquin.