Le antenne sono di moderata lunghezza, clavate e uncinate alle estremità. Il capo è largo e i palpi labiali terminano repentinamente poco al di sopra del punto di inserzione della fronte.
La colorazione dominante dei rappresentanti di questo genere è il marrone più o meno scuro, con varianti giallo-fosche; in alcune specie l'addome presenta una banda bianco-argentata, più o meno ampia, sul quarto segmento. Le ali, esse pure di colorazione principalmente bruna, presentano in talune forme, disegni o campiture bianche o gialle, di geometria variabile.
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Drury, 1773 - Illustrations of natural history; wherein are exhibited ... Illust. Nat. Hist. Exot. Insects 2: 1-90, pl. 1-50
(DE) Freina, J. de & Witt, T. J., Die Bombyces und Sphinges der Westpalaearktis (Insecta, Lepidoptera), Band 1, Monaco, Edition Forschung & Wissenschaft Verlag GmbH, 1987, pp.708;46tavv., ISBN3926285001, OCLC60026319.
Hemming, Francis, 1937 - HÜBNER, A bibliographical and systematic account of the entomological works of Jacob Hübner and of the supplements thereto by Carl Geyer, Gottfried Franz von Frölich and Gottlieb August Wilhelm Herrich-Schäffer, Vol 1 & 2
Hodges, Ronald W., 1971 - The Moths of America North of Mexico; Fascicle 21; SPHINGOIDEA
Kitching & Cadiou, 2000 - Hawkmoths of the World; An annotated and illustrated revisionary checklist (Lepidoptera: Sphingidae). 256 PP.; Comstock Publishing Associates; ISBN 978-0-8014-3734-2
Linnaeus, 1758 - Systema Naturae per Regna Tria Naturae, Secundum Clases, Ordines, Genera, Species, cum Characteribus, Differentiis, Symonymis, Locis. Tomis I. 10th Edition Syst. Nat. (Edn 10) 1: 1-338 339-824
Opler Paul, Pavulaan Harry, Stanford Ray, Pogue Michael - Butterflies and Moths of North America; Mountain Prairie Information Node
Opler & Warren, 2003 - Butterflies of North America. 2. Scientific Names List for Butterfly Species of North America, north of Mexico.
(EN) Scoble, M. J., The Lepidoptera: Form, Function and Diversity, seconda edizione, London, Oxford University Press & Natural History Museum, 2011 [1992], pp.xi,404, ISBN978-0-19-854952-9, LCCN92004297, OCLC25282932.
(EN) Stehr, F. W. (Ed.), Immature Insects, 2 volumi, seconda edizione, Dubuque, Iowa, Kendall/Hunt Pub. Co., 1991 [1987], pp.ix, 754, ISBN978-0-8403-3702-3, LCCN85081922, OCLC13784377.
Swainson, 1822 - Zoological illustrations, or original figures and descriptions of new, rare, or interesting animals, selected chiefly from the classes of ornithology, entomology, and conchology, and arranged on the principles of Cuvier and other modern zoologists Zool. Illustr. (1) 1: pl. 1-18 (1820) pl. 19-66 (1821) 2: pl. 67-83 (1821) pl. 84-119 (1822) 3: pl. 120-134 (1822) pl. 135-182 (1823)
Tuttle James P., 2007 - The Hawkmoths of North America, A Natural History Study of the Sphingidae of the United States and Canada. The Wedge Entomological Research Foundation, Washington DC; ISBN 978-0-9796633-0-7.