Merian probably drew this Milk Thistle (Silybum marianum) and the accompanying insects from life. There are a number of watercolour studies of Ichneumon Wasps, like that at top right, in a study book (now in St Petersburg) in which she gathered her sketches from nature for use in finished compositions such as this one. Merian was not aware that the wasps are parasitoids that lay their eggs in the caterpillars, rather than being the adult form of the caterpillar.