Focused on the material practices of making insect specimens, I explore how shifting concepts of potential are intricately crafted on the lab bench. Different types of time—from personal histories to imagined futures—are created and entangled as butterflies are made into specimens. Transforming a butterfly into a scientific tool does not merely transform the butterfly, I suggest, but also reciprocally folds back to transform the scientist who makes it. Based on ethnographic fieldwork with scientists in the labs and workrooms at the (...) Smithsonian National Museum of Natural History in Washington, DC and the California Academy of Sciences in San Francisco, California, I follow butterflies and moths (Lepidoptera) as they are collected, euthanized, pinned, genetically sampled for rewilding projects, such as reviving a Californian sand dune ecology, and frozen in biobanks for as-yet-unknown future uses. Through a comparative study of practices at these two sites, I examine how a butterfly can contain multiple types of potential: manifesting its inherent potential as it transforms from caterpillar to butterfly, the plasticity of the butterfly body as it is crafted into a scientific specimen, and the potential of that specimen to be used as a site for extracting genomic data. Perceptions of time, salvation, loss, and care emerge as specimens are prepared, sampled, and reimagined as solutions for recreating lost ecologies. (shrink)