Syssphinx Larvae of the Lower Rio Grande Valley of Texas with Emphasis on the Life History of Syssphinx tamaulipasiana

ABSTRACT. The larva of Syssphinx tamaulipasiana (Brechlin and Meister) is described and compared with the three congeners with which it co-occurs in the Lower Rio Grande Valley of Texas: S. albolineata (Grote & Robinson), S. blanchardi (Ferguson), and S. heiligbrodti (Harvey). All four species feed exclusively on mimosid trees, but have nearly non-overlapping host use. We illustrate six instars of S. tamaulipasiana from a lab-reared cohort and wild last instars of all four moths, and offer a key to their last instars. Three of the four species (all but S. heiligbrodti) are restricted to the Lower Rio Grande Valley, where they are threatened by urbanization and insularization.