Reprinted with permission from: Rightmyer, M.G. A Review of the Cleptoparasitic Bee Genus Triepeolus (Hymenoptera: Apidae)
TRIEPEOLUS CRESSONII (ROBERTSON)
(Figs. 39, 40, 248)
Epeolus cressonii Robertson 1897: 344 [Lectotype: Illinois Natural History Survey No. 3282a; female, Illinois, Macoupin Co., Carlinville; 15 September 1886; Coreopsis (=Bidens) aristosa]; Webb 1980: 108 [lectotype designation (by W. E. LaBerge)].
Triepeolus cressonii; Robertson 1901: 231.
Triepeolus cressonii cressonii; Mitchell 1962: 466, Fig. 112 [redescription, floral records, illustrations of scutellum, axillae].
Description.—Length ca. 8–10.5 mm; ITW 1.6–2.3 mm. Integument black, often with at least partially red mandible, labrum, scape, pedicel, F1, tegula, and legs, and occasionally with red pronotal lobe and tip of axillar spine; dorsum of mesosoma and metasoma with bands of pale yellow setae. Clypeus sometimes elongate, entirely or partly asetose (female) or entirely covered with dense white setae (male), with moderate to strong midline, and weak larger punctures. Paramedian band clearly separated from other pale setae on mesoscutum in females; usually laterally contiguous with diffuse pale setae on anterior margin of mesoscutum in males. Scutellum moderately to strongly bigibbous; axillar spine triangular, reaching or slightly exceeding scutellar midpoint, apex sometimes apically incurved. Mesepisternum lacking erect, simple setae; with dorsal region of pale, branched setae often restricted to below scrobal groove (sometimes more extensive); lower pleuron asetose, with dense, small punctures (females and few males); or entirely covered with white, branched setae (most males). T1 with very wide, parallel-sided (i.e., BTB and ATB parallel), ovate or quadrate discal patch. T2 with LLB forming weakly to strongly acute angle with ATB. Female: Pseudopygidial area subovate to subquadrate, with distinct basal crescent of shining setae; S5 not or very slightly downcurved apically. Mesosomal and metasomal venter black except for (often sparse) apical bands of pale setae on S2–S4. Male: Pygidial plate relatively narrow, keyhole shaped, with distinct basal transverse ridge; S2–S3 usually with uninterrupted bands of white setae; S4–S5 with apical fringes of brown setae (S4 often with white setae on basal margin of fringe).
Comments.—This species very closely resembles T. helianthi and T. laticaudus. Females of T. cressonii and T. helianthi can be separated by the pseudopygidial area (with a distinct basal crescent of shining setae in T. cressonii, entire area nearly uniformly shining in T. helianthi), the mesepisternum (with dense pale setae more or less restricted to beneath the scrobal groove in T. cressonii, dorsally with more such pale setae in T. helianthi); and by the amount of pale setae laterally on the sterna (present on S2–S4 in T. cressonii, S3–S4 in T. helianthi). The males are extremely similar, but may be separated based on characters of the clypeus (usually entirely covered with white setae in T. cressonii, apically asetose in T. helianthi), paramedian bands (usually laterally contiguous with pale setae on the anterior margin of the mesoscutum in T. cressonii, usually distinct in T. helianthi), and white apical bands of S2–S3 (usually entire in T. cressonii, usually medially interrupted in T. helianthi).
Females of T. cressonii can be differentiated from those of T. laticaudus by the mesepisternum (in T. laticaudus the dorsal third mostly covered by dense, pale setae, and medioventrally the integument between the punctures is distinctly raised, appearing tuberculate; while in T. cressonii the pale setae is more restricted dorsally, and the integument is much flatter between punctures medioventrally). Also, the basal shining setae of the pseudopygidial area are longer in T. laticaudus than in T. cressonii.
Distribution.—USA: Alabama, Georgia, Illinois, Indiana, Kansas, Louisiana, Maryland, Minnesota, Mississippi, Missouri, Nebraska, New Jersey, North Carolina, North Dakota, Oklahoma, Pennsylvania, Tennessee, Texas, South Dakota, Wisconsin.
Floral Records.—Aster paniculatus [= Symphyotrichum lanceolatum (Willd.) Nesom ssp. lanceolatum var. lanceolatum], A. pilosus [= Symphyotrichum pilosum (Willd.) Nesom var. pilosum], Bidens aristosa (Michx.) Britt., Brauneria pallida [= Echinacea pallida (Nutt.) Nutt.], Coreopsis tinctoria Nutt., Gaillardia pulchella Foug., Helianthus annuus L., H. atrorubens L., H. petiolaris Nutt., H. tuberosus L., Monarda sp., Nepeta cataria L., Physostegia parviflora Nutt. ex Gray, Prionopsis ciliata (= Grindelia papposa Nesom & Suh), Rudbeckia laciniata L., Silphium sp., Solidago altissima L., S. serotina (= S. gigantea Ait.), Vernonia baldwinii interior (Small) Faust, V. missurica Raf., V. noveboracensis (L.) Michx.
Seasonal Records.—1 June to 14 October.
Specimens examined.—154 female, 48 male (BERLIN, DAVIS, GAINESVILLE, ITHACA, LAWRENCE, LOS ANGELES, NEW YORK, PHILADELPHIA, STARKVILLE, UNIVERSITY PARK, URBANA, WASHINGTON D.C.).
Reprinted with permission from: Mitchell, T.B. 1962 Bees of the Eastern United States. North Carolina Agricultural Experiment Station Technical Bulletin No. 152.
FEMALE—Length 10 mm.; black, labrum, mandibles, tibiae, tarsi and tegulae testaceous, basal portions of legs testaceous, with darkened areas, spurs piceous, tubercles only faintly reddened along outer margin; space between margin of vertex and lateral ocelli somewhat less than their diameter; cheeks about half width of eyes, narrower below, posterior margin carinate; segments of flagellum beyond the first somewhat longer than broad, piceous below, more blackish above; median length of labrum nearly two-thirds the breadth, apical margin medially with a pair of very small denticles; posterior margin of scutellum broadly outcurved, faintly impressed medially, free part of axillae quite short, tips about reaching mid transverse line of scutellum (fig. 112); wings lightly infuscated, somewhat more deeply so apically, with the usual three subiiarginal cells, veins piceous; face with some rather dense, pale, appressed tomentuii around bases of antennae; margin of pronotum quite de1sely lut narrowly pale tomentose, tubercies with a similar narrow fringe, and pleura with a small transverse tomentose patch near upper third; scutum with a pair of narrow, longitudinal bands of pale tomentum anteriorly on each side of mid-line and a small patch at each extreme side posteriorly; metanotum and adjacent margin of scutellum rather thinly pale tomentose, posterior face of propodeum, except the triangle, thinly pale tomentose on each side; basal abdominal tergum with a transverse, median patch of black tomentuni, with dense yellow tomentum both anteriorly and posteriorly, these about equal and slightly interrupted medially, rather narrowly joined at extreme side; tergum 2 with a subapical tomentose fascia which is slightly interrupted medially, disc with a rather small patch of tomentum on each extreme side; terga 3 and 4 with subapical, tonientose bands, more or less separated from rims of terga toward midline; tergum 5 very thinly greyish tomentose on each side of pseudopygidium; punctures of face above quite coarse, deep and distinct, somewhat separated, interspaces shining, these becoming somewhat finer and quite closely crowded on margin of vertex and on cheeks below, face below with densely crowded, fine punctures, but clypeus with a few very shallow, coarse punctures; scutum rather coarsely and quite closely punctate throughout, the punctures somewhat more distinct on median, anterior area, more densely crowded and indefinite laterally and on scutellum and axillae; pleura below shining between rather coarse and deep punctures, these well separated in part but not sparse, becoming densely crowded and somewhat finer above; punctures of abdominal terga very fine and close but relatively deep and distinct, especially on the more apical terga; pseudopygidium nearly as long medially as the apical breadth, rather closely set with fine setae; sternum 5 broadly convex as seen from beneath.
MALE—Answers in general to description of female; face somewhat more densely, silvery tomentose, this extending over the elypeus; segments of flagellum somewhat shorter. being scarcely longer than broad; venter of thorax densely silvery tomentose, this continuing more thinly over the pleura; terga 5 and 6 with transverse, pale tomentose fasciae; sterna 4 and 5 with apical fringes of curved setae; pygidial plate strongly elevated above disc of tergum 7, apical part beyond the transverse ridge not much loiiger than broad, rather broadly rounded, surface smooth, margin subcarinate, area basal to the ridge with dense but rather shallow punctures and short fine pubescence.
DISTRIBUTION — Minnesota, to the New England states, south to Tennessee and North Carolina; June to September.
FLOWER RECORDS — Eupatoriurn, Helianthus, Poly gala, Pycnctnthemurn and
Vernonia. Robertson (1929) records eressonii on Aster, Bidens, Blephilia, Boltonia,
Helenium, Heliopsis, Lepachys, Rudbeckici, Solidago and Verbena.
This subspecific designation of cressonii is made necessary by the recognition of another form occurring in the Southwest.
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