“Pronotum: Background color light orange (infrequently yellowish), usually with discal and lateral brown to black markings, not sharply delimited, quite variable in development. At one extreme, pronotum black and only lateral and apical margins light; at other extreme, with basal and lateral brownish markings. Punctation dual, smaller punctures minute and moderate in density, larger punctures small and not coarse to moderate and rather coarse. Elytra: Background color light orange, infrequently yellowish, with brown to (usually) black vittae on second, fourth, and sixth intervals, variable in development. At one extreme, with vittae brownish to black and apex of first, and bases of second and third vittae lighter. At other extreme, with dark vittae expanded, in most areas not sharply delimited, with only following areas light: bases of sutural and first intervals, basal half of fifth interval, most of seventh interval (clouded below humerus), and base of marginal interval; apical half of third, fifth, and marginal intervals clouded with brownish to blackish. With seven rows of fine, close, generally regular punctures and a short series behind humerus; fifth and sixth rows often a little irregular to somewhat confused; punctures smaller to apex as usual; inner and outer rows distinct at apex to a little irregular, usually meeting. Ventral surface: Prosternum and mesosternum and (sometimm) abdomen dull orange and often clouded with blackish; metasternues usually light at center, dark to black at side; metepisternum dark brownish to (usually) black; abdomen usually black, with sides, apex, and center at base more or less light; legs irregularly dull orange to irregularly light to dark brownish, sometimes yellowish evident; anterior margin of prosternum in male produced ventrally into a V-shaped lobe, that in female produced into a broadly U-shaped lobe. Length: 4.2 to 5.5 mm” (White, 1968: 88-9).
“A single specimen in the USNM collection from Parada, Mexico determined as C. semimarginatusJacoby is similar to s. vandykei but lacks the dark vitta present on the second elytral interval of s. vandykei” (White, 1968).
USA: CA, UT, AZ, NM, CO; Canada: British Columbia.