Fig. 3. Electron micrographs showing a series of transverse sections from one trachealis cell. (A) Transverse section near the nuclear pole with a cluster of centrally located mitochondria and other organelles. (B) Transverse section cutting across the tip of the cigar-shaped nucleus. (C) Transverse section showing full cross-section of the nucleus. (D) Enlarged version of (A). The inset shows myosin thick filaments (arrows) surrounded by actin thin filaments. All cross sections come from a series of 11 consecutive sections (100 nm in thickness for each section). Scale bar, 1 µm.