Cell Differentiation; Drosophila/embryology; Drosophila/metabolism; Neuropeptides/metabolism; Tendons/cytology; Tendons/metabolism; Trans-Activators/metabolism; Animals; DNA-Binding Proteins/genetics; DNA-Binding Proteins/metabolism; Drosophila/cytology; Drosophila/genetics; Drosophila Proteins/genetics; Drosophila Proteins/metabolism; Epidermal Cells; Epidermis/embryology; Epidermis/metabolism; Epistasis, Genetic; Gene Expression Regulation, Developmental; In Situ Hybridization; Microscopy, Electron; Motor Activity; Muscles/cytology; Muscles/embryology; Muscles/metabolism; Neuropeptides/genetics; Organ Specificity; Protein Binding; RNA, Messenger/genetics; RNA, Messenger/metabolism; Signal Transduction; Tendons/embryology; Trans-Activators/genetics; Transcription Factors/genetics; Transcription Factors/metabolism