Figure 431 from Chapter 16 (Cytoplasmic matrix and cytoskeleton) of 'The Cell, 2nd Ed.' by Don W. Fawcett M.D. Asynchronous flight muscle of the fly Bombylius major. In all axes, actin filaments are in line with rows of myosin filaments; this organization is a distinguishing characteristic of insect muscle. Image from J. Auber, Am. Zool. 7:451-56, 1967. A PDF copy of the accompanying chapter is available on the ASCB's BioEDUCATE website.