This image previously appeared in Terry Bennett's "History of Photography in China: Chinese Photographers 1844-1879", published by Bernard Quaritch in 2013, with the caption:
Fig. 6.46. Pun Lun. Blind musicians, 1870s. Author’s Collection.
See http://gwulo.com/node/31857 for more information.
It is reproduced here with the permission of the author and publisher.