British Insects: Bumblebees and Cuckoo-bees
Subgenus. Subgenus Rhodobombus.
Biology. The larvae feeding on pollen and nectar gathered and prepared by the adult females.
Adult morphology. Queens unlike workers and males in appearance. Adults about 12–18 mm long. Face relatively long; somewhat longer than wide to much longer than wide (about 1.5 times as long). The facial hairs of males black; vertex black haired. The facial hairs of females black; vertex black haired. The clypeus of females with scattered large to medium punctures over most of its surface, including much of the central area. The mandibles of males not bearded. The mandibles of the females round-ended, not oblique. Antennae of the male with the third segment shorter than the fifth (and the 4th about half as long as the 5th); with the third segment considerably longer than the fourth (about 1.5 times as long). Thorax banded (in males), or not banded (in females; black in females, greyish and black-banded in males); in males black across the middle, with pale anterior and posterior bands. The outer surface of the hind tibiae of females with a conspicuous pollen basket, in the form of an elongate, shiny, hairless, area framed by stout hairs; pollen basket mostly framed by black hairs (but these at least sometimes tipped reddish-yellow). The hind tibiae of the males having a fringe of short hairs along the outer margin. Mid basitarsus of females with the distal-posterior margin extended to form a sharp angle of less than 45 degrees, or produced into a narrow tooth or spine. Scutellum of males pale- or predominantly pale-haired.
Abdomen conspicuously patterned; with a contrasting tail. The tail orange-red (over tergites 4 and 6 and merging into the black on tergite 3 in females, grey only on tergite 1 and red on the rest in males). Abdomen without conspicuous banding between the anterior of the tail and the thorax. Sternite 2 of females with a weak rounded transverse ridge between the anterior and posterior margins.
Male genitalia. The sagittae curved inwards around the spatha; rather sharply angled inwards from the middle, otherwise smooth; apices apically turned outwards, obliquely truncate and minutely hooked externally at the tip (but somwhat dilated, only somewhat truncate, and rather conspicuously hooked). The ends of the claspers much expanded to somwhat expanded; dark and horny; conspicuously emarginate and toothed (not internally fringed); with the volsella readily visible at their ends (not fringed internally).
British representation. Recorded from England. Formerly recorded from Deal in Kent, last seen in 1864(or 1837? - see Saunders) and now assumed extinct in Britain.
General comments. The description applies to typical B. pomorum, the only form recorded in Britain.
Illustrations. • British Bombus spp. (1): Saunders. • Male genital capsules of Bombus and Psithyrus.
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Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. British insects: Bumblebees and Cuckoobees. Version: 1st January 2012. http://delta-intkey.com’.