Zynzus usirus

Zynzus usirus Smith
Female. — Length, 6.8 mm. Antenna and head black. Thorax black with pronotum, tegula, lateral margins of mesoprescutum, and most of mesonotal lateral lobes except for posterior margins orange. Legs black with foretibia and tarsus whitish. Abdomen black dorsally and at apex with terga laterally and sterna orange. Wings uniformly lightly blackish infuscated; veins and stigma black. Antennal length to head width as 4.8:4.5. Lower interocular distance to eye length as 2.5:2.3; distances between eye and hindocellus, hindocelli, and hindocelli and posterior margin of head as 0.9:0.8:0.8. Length of hindbasitarsus to length of remaining tarsal segments combined as 1.6:2.5. Sheath with large leaflike scopae, in dorsal view longer than broad, in lateral view with dorsal margin straight and slanting downward to broadly rounded apex (similar to nigropectus, Fig. 683). Lancet short, clublike, with low serrulae and large annular spines, each annulus from 4 to apex with about 6 spines larger and broader than others (Fig. 699).
Male. — Unknown.
Holotype. — F, "Mex., Sonora, 9 mi. SE of Vicam, 11 -VIII1960, P. H. Arnaud, Jr., E. S. Ross, D. C. Rentz" (San Francisco).