Oregon-R embryos were dechorionated as in Rothwell et al. 1999, quickly rinsed in 0.1% Triton X-100, and incubated in heptane for 45 s before adding an equal volume of 19.5% formaldehyde + 2.2–3.3% methanol. The embryos were fixed for 15–30 min at 25°C. Four different preparative conditions were also used: formalin for 5 min, 37.5% EM-grade paraformaldehyde (EM Sciences) for 5 min, heptane presaturated against 0.25% glutaraldehyde + methanol (1:1) for 30 min according to Thomas and Kiehart 1994, and our initial fixation method in the absence of Triton X-100 before or after the fix; otherwise, the post-fix treatment was according to Rothwell et al. 1999. Detection of plasma membrane (PM)-Spectrin requires post-fixation treatments with >0.5% Triton X-100, while Golgi-Spectrin requires 0.05% Triton X-100. Affinity-purified, goat anti–rabbit IgG-Cy5 and goat anti–mouse IgG-fluorescein antibodies (Chemicon) were used to detect primary antibodies. Embryos were imaged according to Rothwell et al. 1999.