23. Bombus (Thoracobombus) opulentus Smith

(Figs 48, 49)

Bombus opulentus Smith, 1861:153 .

Material examined. 8 queens, 328 workers, 24 males (IAB).

Distribution in North China. Primarily on the Bashang plateau, the Yanshan mountains, the Taihangshan mountains, the loess plateau and the Qinling mountains. Abundant at low elevations of the Simatai Greatwall scenic spots of the Yanshan mountains in Beijing. Common at low elevations of the Bashang plateau and at medium elevations of the Wulingshan nature reserve in Hebei, at medium elevations of the Ziwuling nature reserve and the Maijishan forest park in Gansu, at low elevations of the Fuping nature reserve in Shaanxi. Rare at low to medium elevations of the Panshan forest park, the Shangfangshan forest park, the Lingshan nature reserve, the Puwa nature reserve in Beijing, at low elevations of the Jiudingshan forest park in Tianjin, at low to medium elevations of the Taihangshan mountains in Shanxi, at medium elevations of the loess plateau in northern Shaanxi, at medium elevations of the Xiaolongshan nature reserve and the Baishangjiang nature reserve, at high elevations of the Gahai nature reserve in Gansu, and at medium elevations of the Liupanshan nature reserve in southern Ningxia. 78 localities (Fig. 48) between 65–3432 m (IAB).

Similar species in North China. This species is similar in its brown and black colour pattern to B. longipes (see the key; Figs 23, 49).

Distribution in China. Beijing, Tianjin, Hebei, Shanxi, Shaanxi, Gansu, Ningxia (IAB).

Forage plants. ASTERACEAE: Arctium lappa, Cirsium shansiense, Cosmos bipinnatus, Helianthus annuus, H. tuberosus, Senecio laetus; Solidago canadensis; CUCURBITACEAE: Thladiantha dubia; CONVOLVULACEAE: Merremia sibirica, Ipomoea purpurea; FABACEAE: Astragalus adsurgens, A. dahuricus, Campylotropis macrocarpa, Lablab purpureus, Lespedeza bicolor, L. juncea, Melilotus albus, Onobrychis viciifolia, Vicia amoena, V. cracca; LAMIACEAE: Elsholtzia ciliata, E. stauntonii, Leonurus japonicus, L. macranthus, L. sibiricus, Phlomis umbrosa, Salvia deserta, S. farinacea, Stachys chinensis, Vitex negundo; MALVACEAE: Hibiscus syriacus; ROSACEAE: Duchesnea indica; SOLANACEAE: Solanum nigrum, S. septemlobum .