Kokiro Shiraiwa, Qian Cong and Nick Grishin describe this month in ZooKeys a new swallowtail species from the southwest (type locality: USA, Texas, Duval Co.) that they have named Western Giant Swallowtail. The new species, Heraclides rumiko, while very similar to nominate Giant Swallowtail, differs by about 3 percent in its mitochondrial DNA and in characteristics of male genitalia; lucky for us field lep folks, rumiko is also identifiable in the field by wing pattern, wing shape, and shape and size of yellow spots on the upper thorax.
H. rumiko, the authors say, ranges from CA, AZ, NM and TX south to Panama. In central TX it flies with H. cresphontes. Apparently Western Giant Swallowtail is expanding its range northward in CA, possibly because of citrus cultivation (primary host) and increasingly common cultivation of garden rue, another of its hosts (as with cresphontes). H. rumiko is often found in urban areas. In south TX, near its type locality, the authors found larvae on small to medium sized Colima shrubs (Zanthoxylum fagara) throughout ranches and especially along roadsides, which they explain are used by males as flight corridors.
Read the ZooKeys paper at http://zookeys.pensoft.net/articles.php?id=4409 for more information on Heraclides nomenclature and taxonomy.