I've been trying out an 'insect restrainer' for examining live insects (and arachnids) under the microscope, and am pleased with the results. The restrainer is made from the top half of a glass-topped collecting tin, and a circle of plastazote cut to the same size:
For spiders and some types of insect, the restrainer allows them to be held firmly, but gently, while under the 'scope for identification and photography. They can then be released, unharmed as far as I can tell. Examples - the big Tegenaria house spiders need close examination of the male palps for identification, and here is Tegenaria gigantea in the restrainer:
And here is the underside of the harvestman Paroligolophus agrestis - the essential character for confirming females of this one is the tip of the operculum, on the underside - easy to do, but only if the creature will lie still, and upside-down, under the microscope or hand-lens:
And a weevil, Aspidapion aeneum, which feeds on Hollyhocks in my garden. For this one you need to see the furrow on the top of the head, between the eyes:
The restrainer makes it quick and easy to check IDs for some species. The photos are not the best quality (they're taken with a fairly low-spec Canon Ixus 900ti, through the microscope and through the glass lid of the restrainer), but they do make it possible to keep a record of the ID features without having to keep a specimen every time.