Lasioglossum mellipes (Crawford 1907)

Lasioglossum mellipes (Crawford)

Halictus mellipes Crawford, 1907:190 [female].—Cockerell, 1941:343 [locality records, possible taxonomic status].

Lasioglossum mellipes.—Michener, 1951:1107 [Nearctic catalog].—Moldenke and Neff, 1974:52 [locality and flower records].—Hurd, 1979:1957 [Nearctic catalog].—Hurd et al., 1980:28, 65 [flower records].

TYPE MATERIAL.—The female holotype of L. mellipes is in the National Museum of Natural History, Smithsonian Institution. The specimen is in excellent condition and is labeled

Mts. [Mountains] near Claremont [Los Angeles County] Cal.[ifornia] Baker/[collected from] Ribes [handwritten/5051 [handwritten]/ Type No. 12036 U.S.N.M. [red label/Halictus mellipes Type Cwfd [Crawford] [handwritten].

DISTRIBUTION (Figures 695, 696).—Lasioglossum mellipes occurs from Vancouver Island through Washington, Idaho, Oregon, and California to San Diego County. Michener (1951) reported this species from Baja California and this record has been restated by Hurd (1979) and Hurd et al. (1980). Although the occurrence of L. mellipes in Mexico is likely, I have not seen any specimens of this species taken south of the Mexican border.

DIAGNOSIS.—The characteristically sinuate lateral edge of tergum II (Figure 61), presence of an acarinarium on the anterior surface of tergum I (similar to Figure 693), and the yellowish orange mid and hind tarsi of most specimens will separate females of L. mellipes from other Lasioglossum species. Leg color appears to vary clinally with specimens from Oregon and Washington having entirely dark legs and those from San Bernardino and Los Angeles counties in California (the type-locality of L. mellipes) with pale mid tarsi, hind tarsi and hind tibiae. The hind tibiae of specimens from more northern California counties are mostly darkly pigmented with high levels of variation in color pattern occurring. Leg color also varies in the females of L. anhypops, but their lack of an acarinarium and their strongly excavated tergal II edge (Figure 154) will distinguish them from L. mellipes.

Males of L. mellipes can be recognized by their yellowish orange tarsi. As mentioned in the introductory remarks to the trizonatum group, the vestiture of sternum V is highly variable, with that of one male form having elongate, erect lateral hair tufts (Figure 701) and another having a conspicuous median rosette of erect hairs (Figure 702), with apparent intermediates occurring along the central California coastline. Other Lasioglossum males having pale legs in western United States are L. lampronotum and L. titusi, both of which have conspicuously short heads (Figures 487, 633); L. channelense, known only from the California Channel Islands and having a virtually complete pronotal lateral carina (obviously interrupted in the trizonatum males) and a very wide gena that exceeds the width of the compound eye as seen in lateral view (subequal in trizonatum males); and males of L. paraforbesii which lack a conspicuous hair pattern on sternum V (Figure 416) and occur west only to Idaho and Utah (Figure 406).

DESCRIPTION.—FEMALE: As described for L. anhypops except as follows: (1) Length 8.7–10.3 mm (x = 9.5, n = 15); (2) wing length 2.6–3.0 mm (x = 2.8, n = 15); (3) abdominal width 2.7–3.0 mm (x = 3.0, n = 15).

Structure: (4) Head moderately elongate to elongate (Figure 697; length/width ratio 0.88–1.0, x = 0.93, n = 15). (9) Clypeus projecting approximately 0.94 of its length below lower margin of eyes.

(46) Lateral edge of metasomal tergum II evenly sinuate (Figure 61).

Sculpture: (51) Supraclypeal area mostly polished, obscurely granulate laterally (52) punctures separated by their width or less basally, less dense centrally, punctures separated by 1–2 times their width. (53) Clypeus polished; (54) punctation nearly uniform basally, punctures separated by their width or less, apical one-third virtually impunctate. (63) Dorsal surface of propodeum finely striolate only over basal half, posterior half relatively smooth with obscure rugulae.

Coloration: (71) Wing membrane light yellowish brown, pigmentation moderately heavy at base of marginal cell, membrane becoming clearer towards apex. (72) Unlike most species, many specimens with mid and hind tarsi and in some specimens hind tibiae yellowish orange (see above diagnosis).

Vestiture: (74) Pubescence of head pale yellowish brown. (75) Pubescence of thorax mostly pale yellowish brown, white on pronotal lateral angle, pronotal lobe and metanotum. (78) Anterior hairs on metasomal tergum I pale yellowish brown. (80) Acarinarium present (similar to Figure 693), a large glabrous area at base of tergum I, surrounded laterally by elongate fringe hairs that lack a sharply delimited border; opening of acarinarium moderately wide, not sharply delimited, width subequal to width of lateral hair fringe as seen in dorsal view.

MALE: As described for L. anhypops except as follows: (1) length 7.8–9.2 mm (x = 8.4, n = 27); (2) wing length 2.3–2.9 mm (x = 2.5, n = 27); (3) abdominal width 2.0–2.7 mm (x = 2.2, n = 27). (4) Head as in Figure 698 (length/width ratio 0.87–1.0, x = 0.96, n = 27). (68) Clypeal maculation present. (69) Flagellum yellowish orange ventrally, contrasting with dark dorsum. (72) Tarsi yellowish orange, contrasting with dark tibiae.

Vestiture: Sternal vestiture as în Figures 701, 702; (82) hairs on sternum IV moderately elongate, erect; (83) vestiture of sternum V variable, median rosette of erect hairs present (sometimes conspicuously developed), hairs laterad of rosette short, inconspicuous or gradually becoming longer and noticeable towards lateral margin of sternum (see “Diagnosis” section).

FLIGHT RECORDS (Figure 707).—Females of L. mellipes have been taken in all months except November and January. Most specimens have been taken in late June, with 73% of the records coming from May through July. The two females taken in October were from Alameda County, California, and Harney County, Oregon. The female taken in December was also from Alameda County. Males of L. mellipes have been collected from late April through September, with most records from early July. There does not appear to be a significant difference in the flight periods of the two forms of L. mellipes males other than that the males with short hairs on sternum V possibly fly later than the males with long sternal hairs, reflecting the occurrence of the former form in the Sierra Nevada of California.

FLOWER RECORDS.—Females (108): Scrophulariaceae 23%; Compositae 10%; Cruciferae 8%; Ranunculaceae 7%. Males (12): Compositae 58%. Total: 120 in 26 families, 43 genera as follows:

Apocynum 1; Aralia 1; Arctostaphylos 4; Asclepias 1; Asculus 1; Baccharis 1; *Brassica 9(7); *Calochortus 3(2); *Ceanothus 1(1); *Chamaebatia 5(5); Chrysothamnus 5; *Cirsium 1(1); *Convolvulus 1(1); Cryplantha 3; Encelia 1; Eriodictyon 1; Eriophyllum 1; Gilia 1; Grindelia 1; 4; Gutierrezia 1; Haplopappus 1; Horkelia 1; Hyptis 1 Lomatium 1; Lupinus 1; Montia 1; Nama 1; *Penstemon 5(1); Phacelia 5; Quercus 1; Ranunculus 8; Rhododendron 8 Rhus 1; Ribes 3; *Salix 3(1); Salvia 1; *Scrophularia 19(3); Senecio 2; Sisyrinchium 1; Solanum 4; Symphoricarpus 2; Trifolium 2; Verbascum 1.

SPECIMENS EXAMINED.—549.

CANADA. BRITISH COLUMBIA: Gabriola Island, Nanaimo Biological Station, Rocky Point.

MEXICO. BAJA CALIFORNIA: Sierra San Pedro Martin (3 mi S Encinas).

UNITED STATES. CALIFORNIA: Alameda Co.; Amador Co.: Volcano; Butte Co.: East End Pentz Road, Province Creek, West Branch Feather River (2 mi S Stirling); Calaveras Co.: 4 mi S Railway Co.; Colusa Co.: Stonyford, 12 mi W; Contra Costa Co.: Briones Hills, Lafayette, Orinda, 4 mi NE (Russell Property), Richmond Point (San Pablo); El Dorado Co.; Fresno Co.: Florence Lake, Huntington Lake, Sulpher Meadow (Shaver Lake), Watts Valley; Glenn Co.: Plaskett Meadows; Humboldt Co.; Inyo Co.: Independence, North Fork Bishop Creek; Kern Co.: Alder Creek Public Campground, Alta Sierra (5 mi E), Glenville; Lake Co.: North Fork Cache Creek (Hwy 20), Pillsbury Lake; Lassen Co.: Bridge Creek Camp; Los Angeles Co.; Madera Co.: Big Creek at Boggy Meadow (4.75 air mi ESE Fish Camp); Marin Co.; Mariposa Co.: Mariposa, Pleasant Valley, Soap Creek; Mendocino Co.; Modoc Co.: Alturas (20 mi N), Cedar Pass, Davis Creek (5 mi N); Monterey Co.; Napa Co.: Pipe Valley, Samuel Spring; Nevada Co.: Alta, Boca, Camp Arcade, Lake Spaulding, Sagehen near Hobart Mills; Orange Co.: Back Bay, Silverado Canyon: Placer Co.: Auburn (8 mi E), Forest Hill (13 mi E), Great Alpine Creek, Lake Forest (Lake Tahoe); Plumas Co.; Riverside Co.; Sacramento Co.: Citrus Heights; San Bernardino Co.; San Diego Co.; San Joaquin Co.: Stockton; San Francisco Co.: San Francisco; San Luis Obispo Co.: San Luis Obispo; San Mateo Co.; Santa Barbara Co.: Cachuma Campground (Los Padres National Forest), San Co.: The Geysers, Gualala (3 mi S), Mesa Grande, Plantation (4 mi W), Santa Rosa; Tehama Co.: Government Flat, Lassen National Forest (Lost Creek); Trinity Co.; Tulare Co.; Tuolumne Co.; Ventura Co.: Mt. Pinos; Yolo Co.: Davis, Putah Canyon, Rumsey; Yuba Co.: Challenge, Sierra Foothill Field Station (5 mi N Smartville), Sly Creek Reservoir.

IDAHO: Valley Co.: Donnelly. OREGON: Benton Co.: Corvallis; Clackamas Co.: Colton; Harney Co.: Fish Lake (Steen Mts.); Hood River Co.: Odell; Jackson Co.; Jefferson Co.: Warm Springs; Josephine Co.: Grant's Pass, 11 mi N; Klamath Co.: Eagle Ridge; Linn Co.: Roving River Fish Hatchery, Trout Creek Camp (S Santiam Pass); Marion Co.: Marion, Salem; Wasco Co.: The Dalles; Yamhill Co.: Yamhill. WASHINGTON: Island Co.: Coupeville; King Co.: Seattle; Kittitas Co.: Cliffdell.

Because of the variability in male sternal vestiture and the possibility that two species are involved, male records are divided to show the approximate pattern of sternal variation. Intermediate forms from coastal central California are not indicated in the following listing of 35 males with elongate, erect lateral hair tufts on sternum V.

CALIFORNIA: Alameda Co.: Alameda foothills, Berkeley; Contra Costa Co.: Mt. Diablo State Park; Humboldt Co.: Willow Creek; Los Angeles Co.: Arroyo Seco, Tanbark Flat; Marin Co.: Bolinas, Mill Valley; Mendocino Co.: U.C. Hopland Field; San Bernardino Co.: Dollar Lake Trail (San Bernardino Mts.), Lake Arrowhead; San Diego Co.; San Mateo Co.: Menlo Park, Sierra Morena; Santa Clara Co.; Santa Cruz Co.: Mt. Harmon, Santa Cruz (Big Trees); Sonoma Co.: Cloverdale, 2.5 mi NW.

The following listing is comprised of 66 males with median rosette of hairs on sternum V.

CALIFORNIA: Alameda Co.: Alameda foothills, Berkeley, Piedmont, Redwood Regional Park (East Ridge Trail); Amador Co.: lone, 5 mi W (Highway 104); Colusa Co.: Sycamore; Contra Costa Co.: Point Richmond, San Pablo Point, San Pablo Reservoir, Wildcat Canyon; Eldorado Co.: Fallen Leaf, Placerville, 10 mi N; Fresno Co.: Watts Valley; Glenn Co.: Plaskett Meadows; Madera Co.: Sugar Pine; Marin Co.: Inverness, McClure's Beach, Pt. Reyes; Mariposa Co.: Summerdale Campground (Sierra National Forest); Modoc Co.: Upper Rush Creek Campground (10 mi S Canby); Placer Co.: Weimar; Plumas Co.: Antelope Valley, Quincy, 4 mi W; San Francisco: San Francisco; San Luis Obispo Co.: Pico Creek; San Mateo Co.: Menlo Park, Pomponio State Park, San Bruno Mts.; Santa Cruz Co.: Mission Springs; Shasta Co.: Clayton, French Gulch, 5 mi N; Sonoma Co.: Bodega Bay; Trinity Co.: Big Bar, 3 mi NW; Tulare Co.: Milo (15 mi W Mineral King), Three Rivers; Tuolumne Co.: Strawberry, Twain-Harte. OREGON. Jackson Co.: Colestin, Gold Hill; Josephine Co.: Oregon Caves; Klamath Co.: Dairy, 10 mi E. WASHINGTON. Kittitas Co.

Lasioglossum mellipes is a species of sweat bee in the family Halictidae.