British Insects: Bumblebees and Cuckoo-bees
Subgenus. Subgenus Pyrobombus.
Biology. Social insects forming organized communities; the larvae feeding on pollen and nectar gathered and prepared by the adult females.
Adult morphology. Females and workers similar in appearance, the males somewhat different (the males with the yellow banding paler, and the yellow abdominal band is sometimes weaker in workers than in queens). Adults about 10–18 mm long (queens about 15–17, workers 10–14, males 11–13). The ocello-ocular area of females mostly shining and unpunctured, except for sparse puncturing along the inner margin of the compound eye. Face at least as wide as long, or wider. The facial hairs of males yellow; vertex yellow haired. The facial hairs of females black; vertex black haired. The mandibles of the females round-ended, not oblique; females with no posterior tooth. Antennae of the male with the third segment at least as long as the fifth (the fifth being scarcely longer); with the third segment considerably longer than the fourth to with the third segment equalling or only slightly longer than the fourth (i.e., the 4th somewhat longer in proportion to the third than in B. jonellus). Thorax not predominantly ginger-haired; banded (black, with a fairly broad gingery- to mid-yellow (females) or mid-yellow (males) anterior band only, or males pale-banded both anteriorly and posteriorly), or not banded (the anterior pale band sometimes being reduced to a few hairs in females); when banded, i.e. usually, black posteriorly, with a pale anterior band only (in females), or black across the middle, with pale anterior and posterior bands (in males); the light thoracic hairs lemon-yellow (males), or mid-yellow, or gingerish yellow (females). 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. The hind tibiae of the males having a fringe of long hairs along the outer margin. Mid basitarsus of females with the distal-posterior margin broadly rounded to narrow, but if pointed forming an angle of more than 45 degrees, not projected into a tooth or spine. Scutellum of females exclusively black-haired. Scutellum of males black- or predominantly black-haired.
The abdomen with a boad black band involving more than one t anterior to the tail, and a mid-yellowish bar across the middle which often has a central break or may be absent or reduced to a few yellow hairs. The colour of the tail also varies, but it usually exhibits some pink, orange or brown hairs. Abdomen conspicuously patterned; with a contrasting tail. The tail buff, or orange-red, or pinkish, or brownish (the tail hairs varying from pinkish to reddish or orange to brown in females, white in males). Abdomen conspicuously banded between the anterior of the tail and the thorax (usually), or without conspicuous banding between the anterior of the tail and the thorax (the median mid-yellow band being sometimes reduced or lacking); when banded, with a pale band across the middle. The black abdominal band immediately anterior to the tail of females relatively broad, representing 2 or more segments.
Male genitalia. The sagittae rather straight; smooth to the base, neither serrate nor dentate nor hooked externally; apices apically turned inwards and conspicuously sickle-shaped. The ends of the claspers not expanded; dark and horny; not or only slightly emarginate, without teeth; with the volsella inconspicuous (fairly).
British representation. Recorded from England, Wales, Mainland Scotland, Channel Isles, and Ireland. Common and widespread throughout the British Isles in divers habitats, common in gardens. The adults abroad during March to September (females), or May to September (males).
Illustrations. • B. pratorum: queen and worker (photo). • British Bombus spp. (2): 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’.