We use to do histology, which demands good fixation for conserving cellular structure; so the same procedure must be adequate for µCT. After anaesthetising the insect, we use to inject the fixative and/or practising some cuts in the exoskeleton to allow an adequate and rapid contact with internal organs. Then, we let the sample in the fixative for 2-3 hours, depending on the size of the insect. It is important that during fixation it remains completely immersed and not floating on the surface. Sometimes, a ball of parafilm may be necessary for pushing it down into the liquid.