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Known as the Yellow-Banded Bumble Bee.
Yellow-banded bumble bee
Status: Rare, declining since the mid 1990s.
Select food plant genera: Vaccinium, Salix, Rosa, Rubus, Lonicera, Solidago, Aster
Tongue Length: Short
Distribution: Eastern Montana and the Black Hills east to New England and throughout the Appalachian Mountains
Can be confused with B. pensylvanicus and B. occidentalis
Thorax with yellow band(s), T1 black, T2-3 yellow, T4 black, T5-6 black or yellow, face round.
Mid leg basitarsus with the distal posterior corner rounded.
Cheek length slightly shorter than broad, clypeus strongly swollen in the dorsal half, hind basitarsus with the posterior margin strongly and evenly arched. Hair of the head black or with a minority of short pale hairs intermixed. Hair length short and even.
Abdominal T2-3, either or both entirely black, or either or both with varying amounts of yellow; T4 (distally or more) 7 white, much as in lucorum; genitalia essentially same as that of the above (PI. X), averaging somewhat smaller
Bombus terricola terricola.
DESCRIPTION. Queen. Length, 17.5 mm; width at wing bases, 9.5 mm; abdomen, 10.5 mm, width across T2, 9.0 mm; front wing length, 16.0 mm, width, 5.5 mm. Head: Frontal outline broadly triangulate (excluding mouthparts), slightly wider than high; vertical region nearly flat, with rather deep coarse well-separated punctures except smooth and polished for considerable distance laterad and posteriad of lateral ocelli (ocellar half of ocellocular area), this smoothness extended antero-laterad into ocular half of ocellocular area; ocelli situated almost transversely, about as far apart as their diameters, interocellar and ocellocular lines equal; outline of compound eye only little narrower and slightly convergent above than below, little less than 3 times higher than broad; clypeus wider than high, its whole surface covered with small to large punctures, the median ventral area weakly convex; labrum nearly 3 times wider than thick, the ventral margin broadly arcuate, its surface strongly punctate including that on moderately strong tubercles transversely directed medially antero-ventrad, the inter-tubercular depression narrow, shallow and irregularly punctate, the moderately strong labral shelf irregularly arcuate medially; malar space shorter than distance between (and including) mandibular articulations, irregularly convex with few small punctations; flagellum less than li times as long as scape, Fl little less than twice as long as distal width, distinctly longer than F2 but only perceptibly longer than F3, about f as long as F2 and F3 combined. Legs: Mesobasitarsite elongate rectangular, its obscurely rounded posterior angle recessed; outer hind tibial surface irregularly flat, glossy except for weak alutaceous sculpture; metabasitarsite twice as long as widest dimension, the posterior margin arcuate from base to distal end (widest medially), outer surface nearly flat, the disto-posterior angle arcuate and slightly extended beyond antero-posterior angle. Pubescence: Medium in length, even, compact (or dense), some longer and stronger on face, vertex and on distal abdominal terga; metabasitarsal fringe slightly longer on basal one-third beyond stronger and declining in length to distal end. Color: Head black except intermixture of fine dull yellow on face and vertex. Thorax black except golden (buff) yellow on pronotum and transversely on mesonotum from tegula to tegula, dorsally on mesopleurum ventro-anteriad of wing bases, the scutellum with admixture of dull yellow along its posterior half. Legs black (c/. under "Comments"). Abdomen black except T2-3 entirely covered with ochraceous (cadmium) yellow pile, the posterior margin of T5 and ventrolateral margin of T6 with paler yellow hairs. Wings uniformly stained with brown.
Worker. Length, 15.0 mm; width at wing bases, 7.0 mm; abdomen, 8.0 mm, width across T2, 8.0 mm; front wing length, 12.5 mm, width, 4.0 mm. Morphological characteristics otherwise similar to those of the queen, except Fl about H times as long as distal width, much shorter than rectangular F2 and subsequal to F2 and F3 combined. Legs: Similar to those of queen. Pubescence: Structurally similar to that of queen. Color: Head entirely black. Thorax as in queen except absence of noticeable pale pile on posterior scutellar margin. Abdomen as in the queen except pale (yellowish) pile on T5-6 is muched reduced.
Male. Length, 14.0 mm; abdomen, 7.0 mm, width across T2, 6.5 mm; width at wing bases, 6.5 mm; front wing length, 14.0 mm, width, 4.5 mm. Head: Frontal outline (excluding mouthparts) rounded trapezoidal, slightly wider than high; compound eye 21 times higher than wide, more broadly rounded below than above, its inner margin weakly concave outwardly, though more strongly so dorsally; vertex nearly flat, mostly with irregular small to medium punctures except inner half of ocellocular area smooth and polished extending somewhat antero-laterally, the ocular half of ocellocular area with few irregularly arranged medium to small punctures; ocelli situated immediately below supraorbital line in nearly transverse position, each slightly closer together than their diameter, interocellar line little longer than ocellocular line; malar space perceptibly shorter than distance between (and including) mandibular articulations, its surface irregularly weakly convex, with few microscopic hairs anteriorly and especially posteriorly; labrum rectangular, about 2i times wider than thick, its anterior margin arcuate at lateral corners, straight medially; flagellum little less than twice as long as scape, F1 nearly equal in length to F3, distinctly longer than F2 which is slightly longer than wide. Legs: Mesobasitarsite subrectangular, about 3 times longer than wide; hind tibial outer surface evenly convex mid-longitudinally, smooth, polished and devoid of hairs except on its basal third; metabasitarsite 3 times longer than wide, subrectangular, its outer surface nearly flat with recumbent microscopic pile, the posterior fringe longest (near widest dimension of segment), progressively lessening to very short rigid hairs distally. Pubescence: Somewhat longer and noticeably looser than that of queen and worker. Genitalia, seventh and eighth abdominal sterna (PL X). Color: Similar to that of female but generally light areas slightly paler, especially on head (which is usually predominantly yellow below antennal bases) and thorax; middle femur posteriorly and hind femoral fringe with noticeable dull burnt sienneous hairs; abdominal Tl-3 similar to that of female; T5-6 distally (and disto-laterally), T7 (mostly) with pale sienneous yellowish hairs intermixed with some black (variable, see Comments).
Redescribed from hypotypes. Queen, St. Paul, Minn., May 2, 1939, R.W. Dawson; worker, Beaver Bay, Minn., Aug. 7, 1938, R.W. Dawson; male, Beaver Bay, Minn., Aug. 7, 1938, R.W. Dawson [all HEM].
TYPE. Not examined. The type of Kirby cannot be located and is presumed lost; Kirby's colored figure of the $ in Fauna Borealis-Americana (pi. 6, fig. 4) will serve in lieu of the type specimen.
TYPE LOCALITY. Canada (Northwest Territories?). Number of specimens at hand: 703. In flight: late April to early October, the males on the wing in early July. Distribution: (vertical), sea level to 6800 ft; (horizontal), transcontinental in Canada, and from Maine southward to Tennessee (and likely western Georgia), thence northwestward to Montana. Floral visitations: Achillea, Angelica, Apocy-num, Aster, Caragana, Cichorium, Cirsium, Donicera, Echium, Epilobium, Eupa-torium, Medicago, Melilotus, Rhododendron, Rosa, Rubus, Salix, Solidago, Spiraea, Vaccinium, Verbena, Veronica, and Vicia. Lutz and Cockerell (1920) added the following compiled records: Aesculus, Aralia, Cornus, Gaultheria, Gaylusaccia, lmpatiens, Rhodora, and Viburnum. Leonard et aL (1928) added: Ledum, Oxy-coccus, and Potentilla, and Mitchell (1962) further compiled: Lonicera, Phleum, (Pyrus), Malus, and Pinus with a query (c/. statement under ternarius with respect to coniferous records).
COMMENTS. Little morphological variation of significance, other than size, has been noted in this subspecies. The smallest workers seen are between 8 and 9 mm long, the others ranging in size up to that given for the queen. Chromatically, however, there is considerable variability shown in all three castes. The yellow is often pale (maize yellow) and not the more typical golden yellow. The head of the queen and worker might as often be entirely black as with a suffusion of yellow on the face and vertex. The scutellum is usually black or predominantly so, but often is variously covered with yellow, and the usual black between the wings might be intermixed with yellow, sometimes almost all yellow. Thoracic pleura of the female sometimes predominantly yellow above, the usual pale lobe anterior to wing base being extended ventrad to cover nearly all the upper half of the mesopleurum; and, often in the male the thoracic pleura are almost entirely yellow. Corbicular fringes range from entirely black to predominantly burnt sienna. Rarely is the female abdominal Tl all yellow, but it is common to find specimens with varying amounts of tawny yellow intermixed, especially laterally, with the usual dominant black on this tergum. The presence of variable amounts of yellow on the male abdominal Tl is common. It is not unusual to note considerable black intermixed with the yellow (especially medially) along abdominal T2 anterior margin of otherwise typical females of this subspecies, this showing a trend toward and mergence with what was described by Franklin (1912: 271) as subspecies nigroscutatus under occidentalis Grne. (c/.). Sometimes the female abdominal terga beyond T2 are entirely black; all gradations existing from that described for T4-6 to the condition where there is a considerable intermixture of yellow on T4, and T5-6 are entirely brownish to very pallid yellow. The chromatic variability of the male abdominal terga is even more pronounced than that of the female; often T5 is almost entirely yellow, and the pile on the distal terga (especially T6-7) is pale burnt sienna, similar to that indicated for some hairs on the legs.
Compared with many other bumblebee taxa, t. terricola is among the more constant in color pattern. Yet, the quantity of material examined from all parts of the distribution clearly reveals a marked chromatic variation, particularly amongst the specimens collected in the southeastern and northwestern areas of its range. In the north central and western regions many specimens of all castes assume a coloration that completely merges with that of t. occidentalis (cf.) by way of what Franklin described as nigroscutatus. While typical far western t. occidentalis averages somewhat larger and would chromatically appear to be specifically distinct from terricola as described by Kirby, there are to me no evident constant or reliable morphological features by which specimens of these two overlapping (allopatric) populations can be positively differentiated in these areas of overlap. In such allopatric locations, obviously the two subspecies (terricola and occidentalis) interbreed and produce numerous perplexing subspecific hybrids.
Bombus terricola occidentalis
DESCRIPTION. The following descriptions are based on typical specimens representing the bulk of the far western populations of this subspecies.
Queen. Structurally not perceptibly distinguishable by any significant feature from that of /. terricola. Color: Head black except intermixture of drab brownish yellow on face, especially below antennal bases where such longer hairs tinged with burnt sienna, and on vertex. Thorax above from tegula to tegula and a little lobed ventrally anteriad of each, golden yellow; remainder of thorax black except intermixture of noticeable brownish yellow especially on posterior half of scutellum and less so on lateral portions of interalar area. Legs and wings as in t. terricola. Abdominal Tl, basal third of T4 black with few scattered hairs on T2-3 tipped with brownish yellow, remainder of T4 and 5-6 whitish except some shorter finer pile laterally on T6 with pale golden tinge evident under strong illumination.
Worker. Structurally like that of /. terricola. Chromatically like queen except intermixture of yellow on face and vertex less, only very slight intermixture of yellow on thoracic dorsum posteriad of tegulae; wings somewhat paler.
Male. Structurally like that of t. terricola. Color: Head black and golden yellow, latter color predominating on face between and below antennal bases and on vertex, black pile above antennal bases with considerable intermixture of tawny yellow. Thorax above mostly ochraceous (yellow) except for poorly defined interalar black band, thoracic pleura black except for ochraceous (yellow) ventral extension anteriad of wing bases and most of remaining pleural pile tinged with burnt sienna. Legs black, most pile on coxae, trochanters, and ventrally on femora with considerable tawny yellow, that posteriorly on middle tibia and hind tibial fringes largely pale burnt sienna. Wings lightly, evenly stained with brown as in worker. Abdominal Tl-3 and narrow basally on 4 black, the remainder of 4-7 whitish. Sterna 6-7 and genitalia as in terricola (PI. X).
Re-described from hypotypes. Queen, Robson, B.C., 20-IV-39, H.R. Foxlee; worker, Friday Harbor, Wash., July 2, 1939, R.W. Dawson; male, same data as worker [all HEM].
TYPE. Not examined. A type (in fluid) which has either lost its identity or is not any longer extant. Evidently, in 1863 Cresson borrowed the Greene material from the Smithsonian Institution (Washington) and, if any of Greene's specimens still exist, my intensive search has not divulged their whereabouts.
TYPE LOCALITY. Washington (State), U.S.A., and (Vancouver Island, British Columbia, Canada). Number of specimens at hand: 1444. In flight: from late February or early March to ca. mid-November, the males first appearing in early June. Distribution: (vertical), from sea level to 12,500 ft; (horizontal), Alaska (including major Aleutian Islands), and in Canada south and southeastward to British Columbia, Alberta, and Saskatchewan, and in the United States eastward to the Dakotas and southward to Arizona and New Mexico. Floral visitations: Aster, Chamaenerion, Cleome, Epilobium, Gypsophila, Lotus, Medicago, Melilotus, Peta-sites, Potentilla, Rubus, Rudbeckia, Sonchus, Taraxacum, Trifolium and Zinnia. From Lutz and Cockerell (1920) we can add Monarda and Solidago.
COMMENTS: After having examined thousands of specimens of all castes of t. terricola and t. occidentalis I unhesitatingly agree with Handlirsch (1888a: 234), who first recognized that these forms were conspecific. Franklin (1912: 239, 272), who kept them apart was, however, aware that such a combination might be so.
As stated in the remarks appended to the description of t. terricola, I have not discovered reliable morphological characters that will justify a specific recognition of occidentalis Grne. Superficially, some far western populations appear to average slightly larger than those of t. terricola, but even this might be statistically questionable.
This subspecies shows a broad range of chromatic variability which is, in my opinion, associated with effects by a tolerance for and establishment in many different physical and biological habitats. The subspecies has numerous synonyms, as indicated.
Often the queen head is predominantly black, as is usual in the worker. From the typical described above, the most pronounced variation in the female is the amount of yellow on the thoracic dorsum, on abdominal Tl-3, and the complete mergence of whitish pile on T4-6 to the pale or tawny yellow that occurs on typical t. terricola; often a narrow to wide well-defined inter alar black band occurs, and sometimes the thoracic dorsum is almost if not entirely yellow; abdominal T3 frequently entirely, T2 in part (especially laterally) to almost entirely covered with yellow, and on paler specimens some yellowish pile is evident on Tl, and often irregularly on T4 replacing black or whitish pile. These female color variations from the typical t. occidentalis to t. terricola range mostly through the described synonyms proximus Cr. (1863a: 98), perixanthus C. & P. (1899a: 386), and nigroscutatus Fkln. (1912: 271). The male varies in color from that described above to specimens covered predominantly with golden yellow on head, thorax and abdominal Tl-4, with only traces of black on head, between wing bases, on metapleurum and abdominal Tl; legs of such pale specimens are also mostly yellow, the tibial fringes tinged with pale burnt sienna; and, base of abdominal T4 narrowly blackish, remainder and T5-7 pallid yellow to whitish.
By gross microscopic examination it is not always possible to positively separate many specimens of t. occidentalis (especially workers and males) with credible accuracy from those of L terricola taken in certain northwestern allopatric locations.
Extracted from: Laverty T.M., & Harder L.D., (1988). The Bumble Bees of Eastern Canada. Can. Ent. 120: 965-987.
Description. Body size of all castes medium. Head broadly rounded, malar space slightly wider than long. Tongue short. Colour pattern usually as in Figure 2a and c. In all castes, some individuals with scutellum yellow and well-defined interalar band (Fig. 2b).
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