Alice Butt was JW's model.
Butt posed for JW for Alice Butt (1) (YMSM 437) and Alice Butt (2) (YMSM 438). The technique and butterfly signature, which appears to be part of the original painting, suggest that it was painted in the mid 1890s. However, according to F. G. Macomber, Alice Butt (1) (YMSM 437) was given by JW to Théodore Duret in Paris in 1883. McLaren Young suggested that it could have been painted in Chelsea in the early 1880s and that the French title Une Jeune Fille des Rues used at the time of the Boston exhibitions in 1904 and 1934 was Duret's rather than JW's. Alice Butt (1) (YMSM 437) may be a study for Alice Butt (2) (YMSM 438), as the colour scheme is unresolved. Butt looked Italian, and was depicted by JW with bright, although nervous expression.
UK census 1881, from http://www.familysearch.org (accessed 2004); Young, Andrew McLaren, Margaret F. MacDonald, Robin Spencer and Hamish Miles, The Paintings of James McNeill Whistler, New Haven and London, 1980.