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1957
The Lepidopterists' News
151
TAXONOMIC HISTORY AND DISTRIBUTION OF OCHLODES YUMA (HESPERIIDvE)
by J. W. Tilden
This paper is an outgrowth of the meetings of the Western Section of the Lepidopterists' Society. It was started as an enumeration of the specimens of Ochlodes yuma taken on the annual field trip in 1954 to the Sand Dunes near Antioch, Contra Costa County, California. Interest in the matter has led to an extension of the original idea, which nevertheless remains a contribution from the members of the Western Section.
Ochlodes yuma was described by W. H. Edwards from an unique among the collections of the Wheeler Expeditions. It was described in 1873 from material collected in 1871 "in Arizona." Edwards assigned the species to Hesperia from which it was removed in 1921 by Lindsey and placed in Augiades. This name is unavailable, and its members have been placed in Ochlodes Scudder (1872) with nemorum Boisduval (1852) as orthotype. Famphila scudderi Skinner (1899) has been considered a synonym of yuma by most American workers. The type material hailed from the White River in Colorado. Lack of sufficient material for study leaves the status of scudderi uncertain. It may be, as it is now considered, an out-and-out synonym, a subspecies, or a sibling species.
Previous to 1920, material of Ochlodes yuma was exceedingly scarce, and most of the major papers on American Skippers have little to say about it. Since that time, a fair number of specimens has been taken, mostly in Inyo County, California. In 1932 a specimen was taken near Modesto, California. In 1939 another was found in Calaveras County, California. In the early 1950's it was located at Antioch, Contra Costa County, by Paul Hurd, Jr. It may be mentioned here that the male is illustrated as the "Sand-hill Skipper" in the article called "Sand-dune Insects" in Life Magazine, August 8, 1955. In addition to the eleven specimens of O. yuma taken by members of the Lepidopterists' Society on September 5, 1954, subsequent collectors have found the species at the Antioch Sand-dunes. Since specimens have been taken there in June and September the insect must be double-brooded at that locality as it is in Inyo County.
An examination of the known Californian localities for Ochlodes yuma reveals these constant features: all localities are near water; in some respects each locality represents an oasis or moist spot in otherwise arid country; rank grasses usually grow at the locality. The species has never been found in truly arid spots far from water. Nothing is known about the life-history of the species, but its foodplant is expected to be a grass. The Sand-dunes area near Antioch is rapidly disappearing before the expansion of industrial sites. However, it seems likely that diligent search of the little-collected lowlands in the San Joaquin Valley will result in finding other colonies of the species.
Brigadier Evans (1955) has stated that he considers Ochlodes yuma to be a form of sylvanoides. This seems unlikely. The first brood of yuma appears in late spring, June. O. sylvanoides appears later in the year, toward
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TlLDEN: Ochlodes yuma
Vol.11: nos.4-5
the end of summer. The fall brood of yuma appears in August and flies through September. It is found with sylvanoides, but there is no evidence that the two intergrade. Ochlodes yuma has a colonial type of distribution while sylvanoides exhibits a blanket or matrix type. I find it difficult to believe that the two are one species. Incidently, studies of sylvanoides, so far incomplete, suggest that what we now consider a single species may be a complex of siblings. I shall consider yuma to be a distinct species.
Distributional Data
ARIZONA: "Arizona," the type; also in Henry Edwards Collection, AMNH* (Rindge); MCZ (Forbes); USMN (Field). COCONINO CO.: Indian Gardens, Grand Canyon National Park, 23-24.vii.24 (leg. E. L. Bell) in AMNH (RINDGE) and also 24.vii.34 and 18.vii.38 (both leg. E. L. Bell) in collections of the Naturalists' Workshop at Grand Canyon (SCHELLBACH); Cameron, l.viii.50 (leg. COHN, BOONE, and CAZIER) AMNH (Rindge). PIMA CO.: Tucson, no date, USNM (FIELD). YAVAPAI CO.: Prescott, 12.vii. USNM (Field).
CALIFORNIA: CALAVERAS CO.: Sand Flats, 28.V.39, (leg. T. W. Davies). CONTRA COSTA CO.: Sand Dunes, nr. Antioch, 5-22.ix.54 (leg. DAVIES, LANGSTON, MacNeill, Powell, Patterson, Tilden, Thorne) in collections of collectors, also, 19.vi.55 (leg. SAMUELSON) in Samuelson collection. INYO CO.: Darwin Falls, 19.vi.50 (leg. NlCOLAY and MARTIN) in Nicolay collection, also, 19.vi.51 (leg. HULBIRT) in Hulbirt collection, also, 17.vi.52 (leg. TlLDEN) in Tilden collection, Brown collection, USMN (Field), also, 28.ix.30 (leg. Hardin) in LACM; Deep Springs, l6.vii.53 in J. W. McSwain collection; Haiwee, ll.vi.21 in LACM; Olancha, 6-21.vi.37 (leg. MARTIN) in LACM and USNM (Field), also, 10-20.vi.25 in AMNH (Rindge), also, 28.vi.50 (leg. TlLDEN) in Tilden collection; Owens Lake, 20.vi.37 in Henne collection. MONO CO.: Farrington Camp, no date (leg. F. W. FRIDAY) in LACM; Mammoth Camp, l.viii.27 and no date (leg. F. W. Friday) in LACM. STANISLAUS CO.: Modesto, 7.ix.32 (leg DOLMAN) in Tilden collection.
COLORADO: RIO BLANCO CO.: White River, 24.vii and 13. viii, cotypes of scudderi in AMNH (Rindge), also 24.vii - 13.viii, cotypes of scudderi in Scudder collection, MCZ (FORBES); 24.vii - 13.viii, cotypes of scudderi in Academy of Natural Sciences, Philadelphia.
*ANMH = American Museum of Natural History, New York, N.Y. LACM = Los Angeles County Museum, Los Angeles, Calif. MCZ = Museum of Comparative Zoology, Cambridge, Mass. USNM = United States National Museum, Washington, D.C. Note: According to CLENCH there are no specimens in the collections of the Carnegie Museum.
References Bell, Ernest L., 1938. The Hesperioidea. Bull. Cheyenne Mt. Museum 1, pt.l: p.24. Comstock, John A., 1927. Butterflies of California: p.222, pi.61: figs.16, 17, 18. Edwards, W. H., 1873. Descriptions of diurnal Lepidoptera found within the United
States. Trans. Amer. Ent. Soc. 4: p.346. Evans, W. H., 1955. A Catalogue of the American Hesperiidce, Pt.IV: pp.342-343. Holland, W. J., 1930. The butterfly book. Rev. ed.: p.379, pl.LIII: figs.l, 2. Lindsey, Arthur W., 1921. The Hesperioidea of America north of Mexico. Univ. Iowa
Studies Nat. Hist. 9 (4): p.77. Lindsey, A. W., E. L. Bell, & R. C. Williams, Jr., 1931. The Hesperioidea of North
America. Denison Univ. Bull. Journ. Sci. Labs. 26: p.96. Skinner, Henry, 1899. in Ent. News 10: p.lll.
, 1900. in Ent. News 11: pl.II: figs.9, 10. Skinner, Henry, & R. C. Williams, Jr., 1924. On the male genitalia of the Hesperiidae
of North America. Trans. Amer. Ent. Soc. 50: pp.145-146. Scudder, Samuel Hubbard, 1872. Systematic revision of American butterflies. Rept.
Peabody Acad. Sci. 1871: p.78.
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