Extracted from: Milliron H.E., (1973). A Monograph of the Western Hemisphere Bumblebees (Hymenoptera: Apidae; Bombinae). The Entomological Society of Canada, No. 89.|
Bombus balteatus Dahlb., 1832, p. 36, (necignitus v. balteatus Skor., 1933b, p. 61): Alpinibombus [sic!] balteatus, Skor., 1937b, p. 58 (p.p.): Alpinobombus kir byellus, Skor., 1922a, p. 151, (p.p., list), [n. syn.]: Bombus batteatus [sic!] Ezl.,
1859, p. 144, (= balteatus Dahlb., 1832, p. 36): Bombus kirbyellus, auctt., (nec kirbiellus Curt., 1835a, Append., p. xii): Bombus kirbyellus v. lysholmi Fr., 1904c, p. 519, [n. syn.]: Bombus tricolor Zett., 1838, p. 474, (nec tricolor
Dahlb., 1832, p. 41, $ not $ = Apis cullumana Kby., 1802, p. 359), [n. syn.]: Bombus (B.) kirbyellus, Fkln., 1912, p. 290, (p.p*): Bombus (B.) (Kirbyellus group) Fkln., 1912, p. 289, (p.p.): Bombus pleuralis, Fr., 1902, p. 486, [n. syn.]: Bombus (Alpinobombus) balteatus v. arizonensis, Brs., 1951, p. 1253, In Muesebeck et al, (nec ignitus v. balteatus Skor., 1933b, p. 61), [n. syn.]: Bombus (Alpinobombus) balteatus v. alexanderi, Brs., 1951, p. 1253, In Muesebeck et al., (nec ignitus v. balteatus Skor., 1933b, p. 61), [n. syn.]: Bremus (Alpinobombus) kirbyellus v. alexanderi Fris., 1927c, p. 66, (nec kirbiellus Curt., 1835a, Append., p. lxii), [n. syn.]: Bremus (Alpinobombus) kirbyellus v. arizonensis Fris., 1927c, p. 66, (nec kirbiellus Curt., 1835a, Ap pend., p. lxii), [n. syn.]: Bremus kirbyellus v. alexanderi Fris., 1923b, p /308,
(nec kirbiellus Curt., 1835a, Append., p. lxii), [n. syn.]: Bremus kirbyellus v. arizonensis Fris., 1923b, p. 309, (nec kirbiellus Curt., 1835a, Append., p. lxii), [n. syn.]: Megabombus (M.) (Alpinus group) Mlrn., 1961a, p. 57, (p.p*): • • • balteatus, Mlrn., 1960a, p. 89, ( $ H.E.M. lectotype): . . . tricolor, Mlrn.,
1960a, p. 97, ( $ H.E.M. lectotype).
Description. Queen. Length, 23.0 mm; width at wing bases, 10.0 mm; abdomen, 12.0 mm, width across T2, 9.5 mm; front wing length, 17.0 mm, width, 6.25 mm. Head: Frontal outline (excluding mouthparts) broadly trapezoidal, about as wide as high, dorsolaterally rounded; vertical region weakly concave to nearly flat laterad of ocelli; ocelli situated in nearly straight transverse line, removed from one another by their widest diameter, the lateral ones little farther apart than each is from upper inner margin of compound eye, contiguous to supraorbital line; ocular half (or more) of ocellocular area rather weakly irregularly punctate, the ocellar half (or less) smooth and polished, the vertex laterad and behind with rather numerous medium punctures; outline of compound eye more narrowly rounded above than below, the inner margin nearly straight, about 3f times higher than greatest width; clypeus only slightly wider than high, rather strongly convex dorsally and laterally, less so over median area, covered with medium punctures becoming small, shallow, and less numerous on disc; labrum mostly covered with short straight hairs, slightly more than twice as wide as thick, its ventral margin irregularly arcuate, its tubercles ventrally flat, roughly punctate, mesially as far apart as about the length of F2; malar space If times as long as distance between (and including) mandibular articulations, smooth and weakly convex except dorsoventrally strongly concave at juncture with lower para- facial region; flagellum If times longer than scape, FI distinctly longer than F2 and subequal to F3, about 11 times as long as F2-3. Legs: Mesobasitarsite little less than 3 times longer than greatest width, its outer surface evenly rather deeply concave mid-Iongitudinally, the distoanterior angle arcuately rounded in recess of the acutely rounded distoposterior angle; outer hind tibial surface microscopically alutaceous, convex mid-longitudinally from base to well beyond middle; metabasitarsite with outer surface broadly evenly concave mid-longitudinally, covered with short recumbent pubescence, slightly more than 21 times longer than its widest dimension, the arcuate distoanterior angle a little in recess of the acutely rounded distoposterior angle, distal margin nearly subtruncate, the posterior margin weakly evenly arcuate. Pubescence: Noticeably longer and looser on face, vertex, posteriorly on scutellum, and on most of abdomen; otherwise, finer, denser, and more even than that of kirbyellus; corbicular fringe rather dense, nearly straight basally to weakly unevenly arcuate distally, for the most part distinctly longer than greatest width of corbicula; basal half of metabasitarsal posterior fringe rather short, loose, arcuate, beyond very short to absent distally. Color: Head black with slight admixture of yellowish hairs on vertex; thoracic dorsum anteriad of tegulae, upper half of mesopleurum beneath and forward of tegula, most of scutellum and abdominal Tl-2 ochraceous yellow; interalar black band definitive, moderate in width; all thorax below, legs, abdominal T3 (except distal margin), and most of abdominal venter black; distal margin of abdominal T3, T4-6 covered with pale fulvous to whitish pile (usually the latter predominantly white, sometimes largely rufescent often resembling that in kirbyellus, or predominantly black); wings lightly infumated throughout.
Worker. Length, 13.0 mm; width at wing bases, 6.5 mm; abdomen, 7.0 mm, width across T2, 6.5 mm; front wing length, 11.5 mm, width, 4.0 mm. The morphology of this caste is in all respects relatively similar to that of the queen, except that the taxonomic features of average sized specimens are naturally more diminutive. Color: Head entirely black except some ad mixture of lighter vertical hairs; wings paler than those of the queen; legs, thoracic pleura (except some palish pubescence beneath and anteriad of tegulae), broad interalar band, abdominal T3, and most of abdominal venter black; thoracic dorsum anteriad of tegulae, scutellum posteriorly and abdominal Tl, T2 (except black along distal margin) stramineous; T4-6 pale rufescent yellow (often whitish to pronounced rufescent).
Male. Length, 17.0 mm; abdomen, 8.5 mm, width across T2, 6.5 mm; front wing length, 14.5 mm, width, 5.0 mm. Head: Frontal outline (excluding mouthparts) narrowly trapezoidal, the dorsal angles broadly rounded, about as high as broad; compound eye slightly more than 2f times higher than wide, somewhat more narrowly rounded above than below, inner margin straight, the outer margin evenly concave outwardly; vertex very weakly concave and irregularly punctate behind ocelli; ocular third (or less) of ocellocular area with weak punctation, the ocellar two-thirds smooth and polished; ocelli situated in weak arc on supraorbital line, some what farther removed from one another than their diameter, the median one located slightly
more forward; malar space If times longer than distance between (and including) mandibular articulations, weakly irregularly convex, mostly smooth and polished; labrum little more than twice as wide as median thickness, its ventral margin truncate with rounded lateral corners, its surface irregularly punctate with weak polished callosities and mostly covered with uneven pubescence; flagellum 3 times longer than scape, FI and F2 nearly equally long, together at most only If times longer than F3. Legs: Mesobasitarsite nearly 4 times longer than greatest width, subrectangular, its distal margin emarginate with equally extended rounded angles, the outer surface only weakly concave in the middle; metabasitarsite subrectangular, slightly more than 3 times longer than greatest width of segment, distally emarginate, its outer surface shallowly concave, its posterior margin weakly evenly arcuate throughout, the posterior fringe mostly long and loose, the longest hairs about twice the extreme width of segment. Pubescence: Moderately long and loose, rather even throughout except somewhat shaggier on abdomen. Genitalia, seventh and eighth abdominal sterna (c/. with kirbyellus, PI. XII). Color: Head black except clypeus and area beneath antennal bases suffused with dull yellow, and most of vertex and occipital region pale yellow; thoracic dorsum anteriad of tegulae, mesopleuron (mostly) and scutellum tawny (or pale) yellow, the moderately wide interalar black band poorly defined and suffused with consid erable ochraceous yellow hairs; legs mostly blackish, the fringes with burnt sienna; abdominal Tl-2 tawny yellow, T3 and basal one-third of T4 black, remainder T4-6 and most of abdominal venter pallid drab yellow with rufescent tinge to white (often T4-6 vivid rufescent); wings sub hyaline as in the worker.
Redescribed from hypotypes. Queen, Lapp[land], Petsamo, 2-7, 1929, Hakan Lind- b[erg]; worker, Saana [Finland], 29-7, 1957, R. Elfving; male, Malla [Finland], 5-8, 1957, R. Elfving [all, HEM].
T y p e . My (1960a: 89) lectotypus $ in the Dahlbom Collection, Zoological Institute, University of Lund, Lund, Sweden.
TypeLocality.Lapponia(Sweden). Numberofspecimensathand:44(ex cluding numerous specimens from the Eastern Hemisphere). In flight: Insufficient records preclude any informative remark. It is probable that the species activity coincides with that of hyperboreus (Schonh.) (cf.). At least it is known that workers appear in late June and that the new queens and males are evident in July-August. Distribution: I have every reason to believe that this species occurs throughout the western range of kirbyellus (Curt.) in the Western Hemisphere, but less commonly. Evidently it ranges from sea level in the offshore islands of Alaska and disjunctly in the Rocky Mountains, possibly as far south as the high elevations in north-central New Mexico. Available records indicate a high altitudinal range of 3500 ft and more. Floral visitations: The following records compiled by Richards (19276: 23) under Bombus belteatus (composite of balteatus (Dahlb.) and kirbyellus (Curt.)) comprise several very questionable visitations, but are given here, as well as under kirbyellus (cf.): Aconitum, Andromeda, Astragalus, rBartisia” [= Baptisia], Campanula, Cir- V slum, Comarum, Geranium, Hieracium, Lathyrus, Leontodon, Lotus, Melampyrum, Mulgedium, Oxytropis, Papaver, Pedicularis, Polygonum, Salix, Sibbaldia, Silene, Solidago, Trichera, Vaccinium, and Vicia. With few exceptions these plant genera occur in the Western Hemisphere, but it is uncertain which should be associated with balteatus (Dahlb.).
Note. VarietiesalexanderidescribedbyFrison (19236: 308) andarizonensis (p. 309) assigned by that author to kirbyellus (Curt.) cannot belong to that species. I have studied the Frison types. The Oslar specimens, upon which these descriptions were based, were never taken at the designated localities in Arizona. The Patagonia Mountains (including the locality Oracle) in Arizona are ecologically unfit for the establishment or survival of any high altitude bumblebee species; certainly not any of those of the high and lower arctic fauna. In 1962,1 visited the “type localities” of the so-called varieties and failed to conclude that they ever existed there. The ecological conditions at the highest of the Patagonia Mountains are unfavorable for the existence of either kirbyellus or balteatus. It is most probable that the Oslar specimens before Frison were actually taken somewhere in the Colorado Rockies, or possibly at some high altitude in north-central New Mexico, but not anywhere in Arizona.
C o m m e n t s . N o troublesome morphological variations are noted, except the usual variation in sculpture referred to in the redescription, and a very slight range in the length of the female malar space. Chromatically, however, specimens of this species exhibit the same variability as is found in specimens of kirbyellus (Curt.) and polaris (Curt.) with respect to the coloration of the abdominal terga beyond T2. In general, it is evident that the female yellow of Eastern Hemisphere balteatus is com monly of a deeper, richer shade than that of Western Hemisphere specimens (cf. this under hyperboreus, Comments), and the physical nature of the pubescence of the latter generally tends to be shaggier, more uneven, and somewhat looser. The body of this species is wider and more robust than that of kirbyellus; the interalar black band is narrower and more definitive in both the female castes and male of kirbyellus throughout the distribution.
This species is in all respects closely related to kirbyellus (Curt.) with which it has been repeatedly confounded by all authorities since 1832. The only reliable means of separating the females is by the difference in length of the malar space and more robust form, these differences often demanding sharp discrimination between this species and polaris (Curt.); coloration is not to be accepted as a criterion for differentiation between these related boreal species (i.e., balteatus, kirbyellus, and polaris).
It should be noted that in the male the following morphological features are useful for the separation of this species from kirbyellus: FI about equal to F2, whereas in kirbyellus it is definitely longer; FI and F2 combined are only little longer than F3, but in kirbyellus these segments are much longer (9:6 mm < 9:5 mm);the penultimate flagellar segment is definitely shorter than F3, whereas in kirbyellus it is only slightly shorter. With respect to the male genitalia of these two species, in balteatus the mesal margin of the outer clasper is strongly concave outwardly, the distal mesal process blunt (in kirbyellus the mesal margin is more evenly concave and the distal process is sharp); the inner squamal margin is more deeply emarginate and its distal and proximal points sharper and stronger than those of kirbyellus; the sagittal heads are narrower and their external points more prominently spinate; distally the volsella is more emarginate with a more pronounced mesoproximal extension or lobe; the distal margin of the eighth abdominal sternum usually is subtruncate or at most with only a moderate median projection; the distal half of the seventh sternum of this
species has somewhat finer, more numerous pubescence than in kirbyellus, and a distal margin that is shallowly emarginate medially. The student is referred to the figure of the eighth abdominal sternum by Richards (1927ft, pi. 1, fig. 6) which represents true balteatus.
The distribution of this taxon in the Western Hemisphere is not properly under stood and more attention should be devoted to its occurrence. It is certain that the species exists in parts of the State of Alaska, including some of its off-shore islands, and at many high altitudes of the Rocky Mountains through Canada and possibly as far south as the north-central part of the State of New Mexico in the United States, thus a range overlapping most of the known western North American distribution of kirbyellus. Some of the specimens which I have examined in the past and assigned to kirbyellus (especially males) might rather belong to balteatus; this invites further detailed study by future students of some of my kirbyellus records listed in this work. It is unlikely that the disclosure of misidentifications will alter significantly the distri butional Western Hemisphere range of balteatus, as now understood. As far as the material available for study has indicated, it is reasonably certain that balteatus does not occur anywhere east of the Rocky Mountains in the Canadian arctic, whereas, in the low Canadian arctic kirbyellus is rather common.
This taxon is treated herein as a distinct species of the Alpinus group. Hereto fore, it has been a source of much confusion with polaris (Curt.) and kirbyellus (Curt.) in both hemispheres.