Zopherus opacus Horn 1867

Zopherus opacus Horn

Zopherus opacus Horn, 1867:161; 1870:272.

Zopherodes opacus, Casey, 1907a:40.

The elytral tubercles in this species are extremely small and widely separated. The broad expanses between tubercles are densely opaque and dull in luster. The pronotal punctures are coarsely muricate and closely spaced, and the prosternum is coarsely and densely, sometimes rugosely, punctured.

MEASUREMENTS.—Length 13.0–20.3 mm; width 4.9–7.2 mm.

TYPES.—Holotype (ANSP 3923) Nevada (no specific locality).

VARIATION.—In one of two specimens from Mono County, California, the elytral tubercles are transversely elongate, with thin linear crests and a bit closer together than usual. Horn had a similar specimen from Nevada, so I assume that this can be regarded as normal intraspecific variation. It should be noted that Casey’s concept of this species was correct, although he had only one specimen in his collection.

SPECIMENS EXAMINED.—21 from the localities that follow. UNITED STATES. CALIFORNIA: 9 miles west of Lone Pine, Westgard Pass and Whitney Portal in Inyo County; Convict Lake and Long Valley in Mono County and Sage Flats (not located). NEVADA: Ruby Substation, 10 miles southwest of Wells (6,000 feet) in Elko County; Cody Basin and Reno in Washoe County. UTAH: State label only. Specimens have been taken from 25 February to 12 August.

Zopherus opacus is most like Z. uteanus Casey but also bears some resemblance to Z. granicollis ventriosus. It displays by far the dullest surface luster of any known member of the genus and should be easily recognized.