 During an egg-exchange in 1858 while he was still teaching, Hellins struck up a correspondence with William Buckler (1814–1884), a graphic and portrait artist who, steadily losing his employment to photography, had started a project to depict the hitherto largely unknown caterpillars of the British moths and butterflies.The two then collaborated until Buckler’s death in 1884, Hellins sending caterpillars to Buckler for painting, and both men making detailed descriptions of the various species.Buckler in return sent Hellins copies of his paintings.