19. Bombus (Thoracobombus) hedini Bischoff (Fig. 22) Bombus silvarum ssp. unicolor Friese, 1905:514 (not of Kriechbaumer, 1870:159 = B. maxillosus Klug), lectotype worker (Tkalců, 1968:49) MNHU examined. China: ‘Sz’-tschwan’, but probably Neimenggu (Williams et al., 2009). Bombus (Agrobombus) hedini Bischoff, 1936:15 (not of Bischoff, 1936:25 = B. bohemicus Seidl), type not seen. Synonymised with Megabombus unicolor (Friese) by Tkalců (1968). China: Gansu. Material examined. 4 queens 262 workers 7 males (IAB). Distribution in Gansu. Abundant at low to medium elevations of the eastern loess plateau, common at low to medium elevations of the southeastern mountains and medium to high elevations of the Qinghai-Tibetan plateau in the southwest (Fig. 22); 27 localities between 1011 and 3432 m (IAB). Distribution in China. Beijing, Tianjin, Hebei, Shanxi, Neimenggu, Shaanxi, Gansu, Ningxia (IAB). Forage plants. ASTERACEAE: Helianthus annuus, Saussurea sp.; FABACEAE: Astragalus bhotanensis, Melilotus albus, M. officinalis; GENTIANACEAE: Halenia elliptica; LAMIACEAE: Dracocephalum heterophyllum, Phlomis sp., Salvia sp.; PAPAVERACEAE: Corydalis sp.; SCROPHULARIACEAE: Euphrasia pectinata; THYMELAEACEAE: Wikstroemia chamaedaphne. 20. Bombus (Thoracobombus) remotus (Tkalc ů) (Fig. 23) Megabombus (Agrobombus) remotus Tkalců, 1968:45, holotype queen BMNH examined. China: Sichuan. Material examined. 5 queens 197 workers 19 males (IAB). Distribution in Gansu. Abundant at low to medium elevations of the southern and southeastern mountains, rare at medium elevations of the eastern loess plateau and Qinghai-Tibetan plateau in the southwest (Fig. 23); 16 localities between 1114 and 2766 m (IAB). Distribution in China. Shanxi, Chongqing, Sichuan, Yunnan, Shaanxi, Gansu, Ningxia (IAB). Forage plants. ASTERACEAE: Arctium lappa, Cirsium monocephalum, Erigeron annuus, Tagetes patula; BUD- DLEJACEAE: Buddleja officinalis; CLUSIACEAE: Hypericum perforatum; FABACEAE: Campylotropis macrocarpa, Lespedeza bicolor, Melilotus albus, Trifolium pretense, T. repens, Vicia cracca; LAMIACEAE: Phlomis umbrosa; RANUNCULACEAE: Anemone tomentosa.

Published as part of An, Jiandong, Williams, Paul H., Zhou, Bingfeng, Miao, Zhengying & Qi, Wenzhong, 2011, The bumblebees of Gansu, Northwest China (Hymenoptera, Apidae), pp. 1-36 in Zootaxa 2865 on pages 12-13, DOI: 10.5281/zenodo.204407