Epeolus rufulus Cockerell, 1941

Onuferko, Thomas M., 2018, A revision of the cleptoparasitic bee genus Epeolus Latreille for Nearctic species, north of Mexico (Hymenoptera, Apidae), ZooKeys 755, pp. 1-185 : 136-139

39. Epeolus rufulus Cockerell, 1941 Figs 81, 82, 96B

Epeolus rufulus Cockerell, 1941. Can. Entomol. 73: 36 (♀).

Diagnosis.

The following morphological features in combination can be used to tell E. rufulus apart from all other North American Epeolus except E. attenboroughi : the mandible has a blunt, obtuse preapical tooth; the preoccipital ridge does not join the hypostomal carina; the mesoscutum is covered in pale tomentum, which is densest anteromedially; the axilla is elongate, extending well beyond the midlength of the mesoscutellum but not as far back as its posterior margin, and the free portion is distinctly hooked; the mesopleuron is closely (most i<1d) and evenly punctate; and T1-T4 have complete apical fasciae. Whereas in E. attenboroughi T1 has a comparatively narrow discal patch (the longitudinal band is more than half as wide as the breadth of the apical fascia in dorsal view) and in females F2 is not noticeably longer than wide, in E. rufulus the discal patch is so wide that the longitudinal band is barely visible in dorsal view and in females F2 is more than 1.2 × as long as wide. Epeolus rufulus is also similar to E. ainsliei in that in both species the axilla is dilated laterally and the free portion is distinctly hooked, and the T1-T4 apical fasciae are complete; however, in E. ainsliei the mandible is simple, the preoccipital ridge joins the hypostomal carina, and the mesoscutum has distinct paramedian bands.

Redescription.

FEMALE: Length 7.6 mm (difficult to gauge in holotype because head detached and glued to collection label, and much of pronotum missing; given instead for non-type specimen most similar in size); head length 1.9 mm; head width 2.6 mm; fore wing length>5.1 mm (margins of both very worn in holotype).

Integument coloration. Black in part, at least partially ferruginous on mandible, labrum, clypeus, antenna, pronotal lobe, tegula, axilla, mesoscutum, mesoscutellum, metanotum, mesopleuron, metapleuron, propodeum, legs, metasomal terga (including pygidial plate), and metasomal sterna. Mandible with apex darker than all but extreme base; preapical tooth lighter than mandibular apex (difficult to see in holotype; described from non-type specimen). Antenna brown and orange in part. Pronotal lobe and tegula pale ferruginous to amber. Mesoscutum orange along lateral margin and with pair of orange markings near posterior margin between midline and parapsidal line. Wing membrane subhyaline, apically dusky. Legs entirely reddish orange (both forelegs missing in holotype, but entirely reddish orange in non-type specimens).

Pubescence. Face with tomentum densest around antennal socket. Clypeus, upper paraocular and frontal areas, and vertexal area mostly exposed. Dorsum of mesosoma and metasoma with bands of off-white to pale yellow short appressed setae. Mesoscutum sparsely covered in pale tomentum. Mesopleuron with upper half sparsely hairy; ventrolateral half nearly bare, except along margins. Metanotum with tomentum rubbed off medially in holotype, but uninterrupted and uniformly off white in non-type specimens. T1 with discal patch quadrangular and very wide, the basal and apical fasciae only narrowly joined laterally. T1 with basal and apical fasciae and T2-T4 with apical fasciae complete, those of T2 and T3 somewhat broader laterally, T2 with fascia without anterolateral extensions of tomentum. T5 with pseudopygidial area lunate, its apex more than twice as wide as medial length, indicated by silvery setae on impressed disc of apicomedial region elevated from rest of tergum. S5 with apical fimbria of coppery to silvery hairs extending beyond apex of sternum by ~2/5 MOD.

Surface sculpture. Punctures dense. Labrum and clypeus with punctures equally dense (i<1d). Impunctate spot lateral to lateral ocellus absent. Mesoscutum, mesoscutellum, and axilla coarsely and densely rugose-punctate. Tegula very densely punctate mesally (i<1d), less so laterally (i=1-2d). Mesopleuron with ventrolateral half densely punctate (i<1d) to rugose; mesopleuron with punctures more or less equally dense throughout. Metasomal terga with punctures very fine, dense (i≈1d), evenly distributed on disc.

Structure. Preapical tooth blunt and obtuse. Labrum with pair of small subapical denticles not preceded by carinae. Frontal keel not strongly raised. Scape with greatest length 1.9 × greatest width. F2 noticeably longer than wide (L/W ratio = 1.6). Preoccipital ridge not joining hypostomal carina, from which it is separated by no less than 1 MOD at its terminal (not visible in holotype because head detached and glued to collection label; described from non-type specimens). Mesoscutellum weakly bigibbous. Axilla large, its lateral margin (L) more than half as long as mesoscutellar width (W) (L/W ratio = 0.6) and tip extending well beyond midlength of mesoscutellum but not as far back as its posterior margin; axilla with tip conspicuously diverging from side of mesoscutellum, distinctly hooked, and axilla with free portion 2/5 its medial length; axilla with lateral margin arcuate and carinate. Fore wing with three submarginal cells. Pygidial plate apically truncate.

MALE: Description as for female except for usual secondary sexual characters and as follows: F2 shorter, as long as wide (L/W ratio = 1.1); mesopleuron almost entirely obscured by white tomentum; S4 and S5 with much longer coppery to silvery subapical hairs; pygidial plate apically rounded, with large deep, well-separated punctures, with the interspaces shining.

Distribution.

Great Plains to American southwest and presumably Mexico, given the close proximity of one collection locality (near Cloverdale, New Mexico) to the Mexico–United States border (Fig. 82).

Ecology.

HOST RECORDS: The host species of E. rufulus is/are presently unknown.

FLORAL RECORDS: The label of one examined voucher specimen indicates a floral association with Heterotheca subaxillaris ssp. latifolia.

Discussion.

In his unpublished thesis, Brumley (1965) synonymized Epeolus rufulus under E. crucis , treating the latter as a valid species. Herein, E. crucis is synonymized under E. compactus for reasons described in the Discussion of E. compactus . Also synonymized under E. crucis was E. novomexicanus , but morphological comparisons suggest that the type of E. novomexicanus belongs to the "pusillus group". Epeolus rufulus is similar in overall appearance to E. ainsliei and E. attenboroughi , and the ranges of the three species overlap to some extent.

Epeolus rufulus appears to be uncommon, or at least uncommonly collected. The male of E. rufulus is described here for the first time. There is very little morphological variation among the few examined specimens, and in all the mesoscutum lacks distinct paramedian bands and is instead sparsely covered in pale tomentum.

Material studied.

Type material. Primary: USA: Colorado: Crowley, 01.ix.1932, M.T. James (holotype ♀ [CUM, catalog number: 0000043]).

DNA barcoded material with BIN-compliant sequences.

Available. BOLD:ADI5469. Specimens examined and sequenced.-USA: Colorado: Stratton (39.2645°N; 102.6681°W) (Kit Carson County), 22.viii.2014, A. Carper (1♂, CUM).

Non-barcoded material examined.

USA: Kansas: Finney (37.9411°N; 100.8811°W) (3.2 km S Garden City), 13.ix.2001, R.W. Brooks (1♀, KUNHM); Nebraska: 2 mi S Alliance (Box Butte County), 13.viii.1959, W.E. LaBerge (1♂, BBSL); New Mexico: ~6 mi E Cloverdale (31.4250°N; 108.8144°W) (Hidalgo County), 21.viii.2004, D. Yanega (1♀, UCR).