By that spring, a young lepidopterist skirting the overgrown lilac might have seen through the windows of the caterpillar room a baby in a crate on the floor, looking among the other boxes filled with plants and dirt like a dahlia. A lovely child, everyone agreed. Marion fussed only when hungry or wet and seemed to enjoy the crate Henrietta had padded with towels and lined with calico. Hester, now convinced that nothing could be better for Marion than continued exposure to the habits of moths and butterflies, would, after nursing her, take up her perch on the stool and, leaning on the workbench, transcribe into a notebook the observations Henrietta dictated.

Surely, Henrietta thought, her niece gained some subtle benefit from watching her aunt and her mother work. By then Henrietta was training the brothers and sisters of her first pupils, and the caterpillar room was so familiar to the village that people dropped by with questions and treasures. A neighbor with a fritillary he’d caught in his cap. Young Sally Sazerat with a fat Promethea cocoon. Little boys brought gold-dotted emerald chrysalides attached to milkweed leaves; farm wives brought fat hornworms they’d plucked indignantly from ravaged tomatoes; Taggart Blake, a favorite student, brought a snowberry clearwing, which he’d mistaken for a gigantic bumblebee. Didier Durand, trailing his younger brother Jasper, brought a tiger swallowtail he thought was a monarch. Even after Marion began to crawl, and then to walk, Henrietta and Hester kept her in the caterpillar room when she was napping. When she woke, they brought her into the house, where their mother could watch her.

On an April Saturday in 1896, Henrietta got her first clue that Marion might not be an only child. A few weeks earlier she’d brought her charges on an expedition she repeated every spring, searching for mourning cloak butterflies in the disappearing snow. Today she’d promised to show them the structure of the wings.

“We talked at our last meeting,” she said, “about the mourning cloak’s long life as an adult and its winter hibernation. Wiley and Sylvia were lucky enough to have their butterflies lay eggs, which are here on the willow twigs in our breeding cages. We’ll be able to follow these as they develop into caterpillars through the summer and then pupate. The specimens that Jennie, Leander, and Carl gathered expired before they laid eggs—but they lived a long time for butterflies, almost ten months, and even dead they have something to teach us.”