Of the two versions of this composition in the Museum’s collection, this one is more freely executed, indicating that it was probably made second. Several of the figures in this pastel differ from those in The Rehearsal of the Ballet Onstage (29.160.26), including the dancer seen from behind on the far left, fingering her bracelet. Both works were executed over an ink drawing on paper, an unusual practice for Degas.

百度翻译：http://fanyi.baidu.com

There are three similar versions of this scene, and their precise relationship has bedeviled scholars for decades. The largest, painted in grisaille (Musée d’Orsay, Paris), appeared in the first Impressionist exhibition in 1874. The two others, tentatively dated the same year, are in the Metropolitan’s collection. This painting probably preceded the version in pastel (29.100.39), which is more freely handled. The importance that Degas attached to the composition is evident in the preparatory drawings that he made for almost every figure, from the dancer scratching her back in the foreground to the woman yawning next to the stage flat.

百度翻译：http://fanyi.baidu.com