More interesting, and morbid, than you thought.
“The belief that butterflies represented the soul was fairly widespread. In the United Kingdom, regional folklore could be quite specific on the matter. For instance, in Ireland, butterflies were thought to be either the souls of dead grandfathers or the souls of the newly dead waiting to pass through Purgatory. While in Devonshire and parts of Yorkshire, they were believed to be the souls of unbaptized babies.” (https://mimimatthews.com/2016/10/14/emblems-of-the-soul-butterflies-in-victorian-fashion-and-folklore/)