Taxonomic History of the Cactus Feeding Clade
The cactus-feeding Phycitinae and their closest relatives have been considered a natural group for approximately 3 quarters of a century. Heinrich (1939) argued that the 18 known then to feed on cactus along with the gooseberry-feeding genus Zophodia formed a natural unit within the subfamily. Later, in his monumental revision of American Phycitinae, Heinrich (1956) further added Rhagea, Baphala and Laetilia to the group comprising the cactus-feeders and Zophodia. He also suggested that the group was closely related to the Homoeosoma Curtis genera group and the Mescinia Ragonot genera group, both of which, to a large degree, feed on Asteraceae (e.g. Simonsen 2008). Roesler (1973) in his treatment of Palaearctic Phycitinae did not treat exclusively new world genera, but nevertheless included all cactus-feeders, and Rhagea, Baphala and Laetilia in the Holarctic genus Zophodia. Blanchard & Ferguson (1975) included a new genus, Rostrolaetilia in the cactus-feeder group based on similarities in male genitalia and larval life style to Laetilia (despite very little available information on juvenile stages of Rostrolaetilia).
Neunzig (1997) treated the cactus-feeders and their allies in a single volume in his series of Phycitinae fascicles in the series “Moth of America North of Mexico”. By restricting himself to the United States and Canada, Neunzig excluded not only the species of predominately North American genera occurring in Mexico, but also six genera that are restricted to South and Central America. Nevertheless, Neunzig’s contribution remains singularly important, not only because it sums up all available knowledge about North America cactus-feeders, but also because it included high quality colour photos of all North American species, thus significantly improving available identification tools. Neunzig (1997) accepted Heinrich’s assessment that the cactus-feeders are close to the Homoeosoma and Mescinia groups and Blanchard & Ferguson’s (1975) conclusion that Rostrolaetilia belong with the cactus-feeders. He also included the genera Welderella Blanchard and Barberia Dyar in the fascicle. Based on similarities in genitalia, wing venation and antenna morphology Neunzig (1997) synonymized the genus Olycella with Melitara.