Longitudinal and cross sections showing ribbon like myofibrils regularly alternating with layers of mitochondria and SR/T tubules. Dyads are located in a grove of the mitochondrial surface. Negatives aere scanned on nikon 8000 at 4000dpi/6.3 micron scan step size, then reduced in size 4X for upload, for an effective pixel size of 25 micron. Technical details: Heads and tail removed, thorax bisected and immersed in 3% glutaraldehyde buffered in 0.1 M cacodylate buffer (pH7.2). Stored at 4C for several days. Muscle dissected out. Rinsed 3Xin buffer, postfixed in 2% PsO4 in buffer, for 1.5 hrs; rinsed 3 times in water, en-block stained in saturated aqueous uranyl acetate, embedded in Spurr. Thin sections stained in uranyl acetate and lead and examined in a Philips 410 Microscope. Reference for the image: Loesser, K.E., Castellani, L. and Franzini-Armstrong, C. Disposition of junctional feet in muscles of invertebrates. J. Muscle Research Cell Motility 13:161-173, 199