Summary
The cervicothoracic musculature of Manduca sexta (Johannson) and of Spodoptera eridania (Cramer) is described and figured. This brings to 12 the number of lepidopterous families that have been so treated, and thus places the Lepidoptera in an exceptionally favourable position for analysis of their general muscular complement. The description of muscles for Manduca and Spodoptera is given in a form that provides a comprehensive classification of the cervicothoracic muscles of this order.