Kemptgen Girls

The Kemptgen girls: Lucy, Margot, mystery girl, & Helen
Helen was my grandmother. Lucy and Margot were her older sisters. I have no idea who the other girl is, but since she appears in many of the photos from this era (around 1918) and bears a family resemblance, perhaps she is a cousin.
Based on the other photos in the album, they were dressed up for a tea party and a visit from the Watels, my great-great grandparents, who emigrated to America from Poland where they were called Watelevich (or some alternate spelling lost to history).