Tomboys show up in the last third of the exhibition, and they come with their own model from American literature. If Daisy Miller exhibited the “audacity and innocence” of American girlhood, the character Jo from Louisa May Alcott’s “Little Women” (1868-69) serves, for Dr. Connor, as the archetype of the American tomboy.

Some of the key works here include John George Brown’s depiction of a young girl, “Swinging on the Gate,” from around 1878 to 1879, and Eastman Johnson’s “Kite Flying” (1865), as well as Homer’s woodcut “A Skating Scene” (1868). Another vernacular image, a Currier & Ives lithograph titled “Into Mischief,” from around 1857, shows a toddler wreaking havoc in a nursery — a rare image of a girl misbehaving, in a cultural landscape that included mischievous boys like Mark Twain’s Tom Sawyer.

The sexual exploitation of children and its traumatic effects on them as adults, particularly women — which were studied by neurologists in Europe like Jean-Martin Charcot and his protégé, Sigmund Freud, and which were formulated as “hysteria” — are generally overlooked here. Seymour Joseph Guy’s painting “Making a Train” (1867), with a young girl playing dress-up in her bedroom, is about as close as the show gets to exploring the eroticism or sexualization of children.

But with many pieces on loan from institutions like the Smithsonian, the Whitney Museum of American Art, the Brooklyn Museum, the Detroit Institute of Arts and the Museum of Fine Arts in Boston, “Angels and Tomboys” is built from the annals of American art, and it offers a portrait of American girlhood that is democratic, probing and, at this moment, oddly topical.