Intestines from 3rd instar larvae of Drosophila melanogaster were dissected, fixed with formalin-acetic acid containing 0.1% Triton-X 100, and squashed on a glass slide. After freezing in liquid nitrogen, the cover slips removed, and the slide thawed and stained with 1% uranyl acetate, rinsed in 50% ethanol, dehydrated and critical point dried (see Ris H, 1981 Stereoscopic Electron Microscopy of Chromosomes, Meth Cell Biol 22:77-96). Grids were observed using the Madison High Voltage Electron Microscope at 1 MeV. Image shows a series of bands and interbands in a polytene chromosome. This image was taken with a tilt angle of 60 degrees. The accompanying grouped image, taken at 45 degrees forms a stereo pair, providing an oblique 3D view of the chromosome.