9. Bombus (Megabombus) trifasciatus Smith

(Figs 20, 21)

Bombus trifasciatus Smith, 1852a:43 .

Bombus ningpoënsis Friese, 1909:676 .

Bombus (Diversobombus) ningpoensis ssp. minshanicus Bischoff, 1936:19.

Taxonomy. For a discussion of the taxonomy of this species complex see Williams et al. (2009) and Hines & Williams (2012).

Material examined. 563 workers, 1 male (IAB).

Distribution in North China. Only in the Qin-Ba mountains in southern Shaanxi and southern Gansu. Abundant at low to medium elevations of the Baishuijiang nature reserve and the Xiaolongshan nature reserve in Gansu, the Heihe nature reserve, the Fuping nature reserve, the Qingmuchuan nature reserve, the Sangyuan nature reserve, the Changqing nature reserve, the Tianhuashan nature reserve, and the Micangshan nature reserve in Shaanxi. Rare at medium elevations of the Maijishan forest park in Gansu, at low to medium elevations of the Shouyangshan nature reserve, the Zhongnanshan nature reserve, and the Niubeiliang nature reserve in Shaanxi. 57 localities (Fig. 20) between 540–2026 m (IAB).

Variation in North China. This species shows strong variation in the colour pattern of the hair across its global distribution (Hines & Williams, 2012). In North China the principal variation is in the relative extent of the yellow and black hair on the dorsum of the thorax (Fig. 21).

Similar species in North China. This species is similar in its red-tailed colour pattern to B. bicoloratus (see the key; Figs 21, 27).

Distribution in China. Anhui, Fujian, Henan, Hubei, Guangdong, Chongqing, Sichuan, Guizhou, Yunnan, Shaanxi, Gansu (IAB).

Forage plants. ASTERACEAE: Arctium lappa, Cosmos bipinnatus, Cirsium monocephalum, Dahlia pinnata, Erigeron annuus, Helianthus annuus, Rudbeckia laciniata; BALSAMINACEAE: Impatiens balsamina; BUDDLEJACEAE: Buddleja officinalis; CARYOPHYLLACEAE: Silene fortunei; CLUSIACEAE: Hypericum ascyron, H. perforatum, Hypericum sp.; CONVOLVULACEAE: Ipomoea nil; CUCURBITACEAE: Cucumis sativus, Cucurbita moschata, Thladiantha dubia; FABACEAE: Campylotropis macrocarpa; LAMIACEAE: Agastache rugosa, Caryopteris divaricata, Clinopodium chinense, Leonurus japonicus, Stachys japonica, Vitex negundo; LYTHRACEAE: Lagerstroemia indica; MALVACEAE: Alcea rosea, Hibiscus syriacus, Malva cathayensis; NYCTAGINACEAE: Mirabilis jalapa; ONAGRACEAE: Oenothera biennis; PAPAVERACEAE: Corydalis edulis; ROSACEAE: Rubus sp., Spiraea japonica; SAXIFRAGACEAE: Astilbe chinensis; SOLANACEAE: Capsicum annuum, Nicandra physalodes, Solanum septemlobum; TILIACEAE: Grewia biloba .