Pierre Veilleux had been an entomological technician at the Montréal Insectarium since the very beginning, after serving as a technician with Insectarium creator Georges Brossard during the two preparatory years that preceded the opening of the institution. He was deeply involved in mounting the various exhibits presented at the Insectarium. Specialized in lepidoptera, he also shared his deep expertise regarding a number of butterfly groups, such as the magnificent morphos, the blue diamonds of the rainforest, and had been inventorying Lepidoptera on the islands of the Montreal area for several years.