Sphecodogastra oenotherae (Stevens)

Sphecodogastra oenotherae (Stevens)

Halictus (Evylaeus) oenotherae Stevens, 1920:37 [female; compared with H. aberrans, H. pectoralis].

Halictus ralenci Crawford, 1932:70 [female].—Mitchell, 1960:365 [synonymy].

Lasioglossum (Evylaeus) ralenci.—Michener, 1951:1110 [catalog],

Lasioglossum (Sphecodogastra) oenotherae.—Michener, 1951:1111 [catalog].

Lasioglossum (Evylaeus) oenotherae.—Linsley and MacSwain, 1962:45 [taxonomy].

Evylaeus oenotherae.—Knerer and Atwood, 1964:958 [taxonomy; noted misi-dentification of male of this species as E. truncatus by Mitchell (I960)].—Knerer, 1969:142 [nesting biology].—Knerer and MacKay, 1969 [biology].—Hurd, 1979:1960 [catalog].—Moure and Hurd, 1987:78 [catalog].

Lasioglossum oenotherae.—Poole, 1996:617 [checklist].

TYPE MATERIAL.—The female holotype of Halictus oenotherae is in the collection of the National Museum of Natural History, Smithsonian Institution. The specimen is labeled “Blue Rapids, Ks.[Kansas] 8/30 P.M. Jun[e] 20 1919 O.A. Stevens/Megapterium missouriense [handwritten]/12033 [Stevens’ type number]/Type No. 23848 U.S.N.M. [red label]/Halictus oenotherae Stevens type” [handwritten]. The type is in excellent condition except for missing the last tarsomere of the left front leg and the last three tarsomeres of the right front leg. The female holotype of Halictus ralenci is deposited in the American Museum of Natural History. It is labeled “Raleigh NC [North Carolina] C S Brimley 29-V[May]-[19]24/Acc. 33827/Halictus ralenci Type Cwfd” [handwritten]. The specimen is missing the last tarsomere of the right middle leg and the entire tarsus of the right hind leg.

DISTRIBUTION (Figure 117).—Sphecodogastra oenotherae is the one member of this genus occurring in far eastern North America. Only texana is also known to occur east of the Mississippi River, being recorded in Wisconsin, IIIinois, and Michigan—states in which S. oenotherae apparently does not occur. I have seen specimens of S. oenotherae from New Brunswick and Ontario, the northern parts of its range. Moure and Hurd (1987) also listed it from Nova Scotia. Its range extends south to Georgia. Interestingly, there are four disjunct locality records of this species west of the Mississippi: Marshall County, Kansas (the type locality); Calcasieu County, Louisiana; and Lee and Upshur counties, Texas. Moure and Hurd (1987) also listed it from North Dakota. Whether this disjunct pattern is real or was a result of inadequate collecting is unknown. The western records make S. oenotherae potentially sympatric, albeit narrowly, with S. texana and S. lusoria and also with S. aberrans if the North Dakota record is correct.

Knerer and MacKay (1969:289) correctly noted that the wide distribution of this species in eastern North America “is seldom reflected in representative local collections.” In this current review of Sphecodogastra based on approximately 3200 specimens, I have examined only 170 S. oenotherae. An effort to collect specimens from Oenothera in the early morning hours and twilight period would undoubtedly extend our knowledge of the distribution of this species. Oenothera laciniata, an evening primrose from which S. oenotherae has been collected, has an eastern distribution (Dietrich and Wagner, 1988) similar to that of S. oenotherae and should be considered a primary target for potential sampling.

DIAGNOSIS.—The coarsely rugo–striate dorsal propodeal surface (Figure 122) easily differentiates both males and females of Sphecodogastra oenotherae from all other known Sphecodogastra.

DESCRIPTION.—FEMALE: (1) Length 6.6–8.2 mm (mean = 7.6, n = 5); (2) wing length 1.9–2.3 mm (mean = 2.1, n = 5); (3) abdominal width 2.1–2.5 mm (mean = 2.4, n = 5).

Structure: (4) Head broad (Figure 118); length/width ratio 0.89–0.94 (mean = 0.92, n = 5). (5) Gena, at midpoint, slightly exceeding compound eye in width. (9) Clypeus projecting approximately 0.67 times its length below lower margin of eyes; (11) clypeal surface without median longitudinal sulcation. (13) Ocular–ocellar distance subequal to distance between lateral ocellus and hind margin of vertex (ocular–ocellar space approximately 2.0 times lateral ocellar diameter); (14) distance between lateral ocelli slightly exceeding ocular–ocellar distance. (16) Inner margins of compound eyes nearly parallel. (21) Scape reaching top of vertex; (22) pedicel subequal in length to flagellomere 1. (30) Mandible elongate, but because of broad head only reaching opposing clypeal angle; subapical tooth somewhat reduced.

(40) Dorsal surface of propodeum about 0.71 times the length of scutellum and approximately 1.25 times the length of metanotum; (44) lateral propodeal carinae very well developed, encircling propodeal surface. (45) Inner hind tibial spur with 4 or 5 moderately elongate teeth (Figure 62).

(46) Lateral edge of metasomal T2 broadly rounded.

Sculpture: (51) Supraclypeal area polished, (52) punctation sparse, most punctures separated by two times their diameters. (53) Clypeus polished; (54) punctation sparse, punctures small, only slightly larger apically, separated by 2–3 times their diameters. (55) Hypostoma obscurely striolate throughout.

(56) Mesoscutum mostly shiny, tessellation confined to anterior one-fourth, (57) punctation as in Figure 123, most punctures separated by 1–2 times their diameters. (63) Dorsal surface of propodeum strongly and entirely striate (Figure 122), (64) surface smooth, not alveolated. (65) T1 shiny and polished, (66) punctation fine, moderately sparse, punctures separated by 1–3 times their diameters.

Coloration: (67) Abdomen dark brown. (69) Flagellum brown. (70) Tegula light brown. (71) Wing membrane pale yellowish brown; veins and stigma light brown. (72) Legs dark brown.

Vestiture: (74) Hairs on head white. (75) Pubescence on thorax white; (76) mesoscutal hairs moderately elongate, approximately 1.5 times median ocellar diameter; mesoscutum and pleuron without short suberect or adpressed hairs. (81) Basal hair bands on T2–T4 weakly developed, inconspicuous; terga lacking apical hair bands.

MALE: As described for female except as follows: (1) Length 7.3–8.1 mm (mean = 7.7, n = 5); (2) wing length 1.92.0 mm (mean = 2.0, n = 5); (3) abdominal width 1.7–1.9 mm (mean = 1.8, n = 5). (4) Head (Figure 119) length/width ratio 1.05–1.09 (mean = 1.07, n = 5). (23) Flagellomere 2 approximately 1.5 times length of flagellomere 1. (37) Median mesoscutal line impressed. (70) Tegula yellowish brown. (73) Short, adpressed hairs on face extending dorsad just below median ocellus. (76) Mesoscutal hairs moderately elongate; short, adpressed hairs inconspicuous to absent; pleuron without short, suberect to adpressed hairs.

Terminalia (Figures 124–127): (84) S7 lateral arms slender; (85) S8 usually developed; apex of median process rounded; (89) retrorse membranous lobe narrow, parallel sided.

FLIGHT RECORDS (Figure 128).—Females of Sphecodogastra oenotherae, like S. antiochensis, were most often collected in late spring (unlike the other Sphecodogastra species examined in this study), with 64% of specimens taken during May. Males were more often collected in later months, with 87% from July and August.

At Toronto, Canada, Knerer and MacKay (1969) reported activity of this species to be much delayed, apparently to coincide with the Oenothera bloom in that area. Females first appeared in mid-June and some nests were not established before July. Males were not observed at flowers until the end of July. Nest activity continued until late August, but all nests remained closed after September. The authors thought S. oenotherae to be univoltine at this latitude.

SPECIMENS EXAMINED.—170 (104 females, 66 males).

CANADA. NEW BRUNSWICK: Nerepis. ONTARIO: Ottawa; Toronto.

UNITED STATES. CONNECTICUT: Fairfield Co.: Stamford. DISTRICT OF COLUMBIA: Washington, D.C. GEORGIA: Dade Co.: Head River; DeKalb Co.: Stone Mountain; Rabun Co.: Rabun Bald; White Co.: Yonah Mountain. KANSAS: Marshall Co.: Blue Rapids. LOUISIANA: Calcasieu Co.: Vinton. MARYLAND: Prince Georges Co.: Greenbelt. MASSACHUSETTS: Worcester Co.: Petersham. NEW HAMPSHIRE: Strafford Co.: Durham. NEW JERSEY: Bergen Co.: Alpine; Closter; Ramsey; Essex Co.: Great Piece Meadows; Morris Co.: Boonton. NEW YORK: Albany Co.: Rensselaerville (Huyck Preserve); Nassau Co.: Floral Park; Rockland Co.: Nyack; Suffolk Co.: Orient Point (Cold Spring Harbor), Set-auket, Sound Beach; Sullivan Co.: White Lake; Tompkins Co.: Ithaca (B. Danforth, pers. comm., 1996). NORTH CAROLINA: Harnett Co.: Lillington, 10 mi S; Haywood Co.; Macon Co.: Highlands; Wayah Bald; Wayah Gap; Transylvania Co.: Rich Mountain; Wake Co.: Raleigh; Watanga Co.: Grandfather Mountain; Yancey Co.: Mt. Mitchell. PENNSYLVANIA: Cumberland Co.: Craigheads. TEXAS: Lee Co.: Lexington; Upshur Co.: Lake McClellan. VIRGINIA: Arlington Co.: Falls Church; Glencarlyn.