Morphology of the Head and Thorax of the Adult Tobacco Hornworm, Manduca sexta (Lepidoptera: Sphingidae). 1. Skeleton and Muscles

The thoracic musculature of the adult Manduca sexta (Johansson) is described and compared with that of Sphinx comvolvuli (L.) and Antheraea polyphemus (Cramer). Those muscles which were described from S. convolvuli could be homologized with muscles of M. sexto . This was not always the case with A. polyphemus . In M. sexta more muscles were observed in the prothorax than were described from A. polyphemus . Since these muscles would provide additional mobility for the head, it is suggested that they may be important for feeding in M. sexta . Additional differences were observed in the mesothorax where the dorsolongitudinal muscles of each side were observed to consist of 10 distinct fasciculi rather than 5 as in A. polyphemus . Minor differences also were observed in the musculature of the 1st abdominal segment of the 3 moths.