Hippolyte Emmanuel Boulenger ( 1837 - 1874 ) was a Belgian painter. Hippolyte Emmanuel Boulenger s works have been put up for auction numerous times, with realized prices surpassing estimated prices, varying from 2905.1 USD for Les nénuphars en fleurs in 2004 to 13187.78 USD for Etang à Tervueren: by the lake in 2007 , based on the size and medium of the artwork.