This quick lab worksheet is a great resource for examining insects or arachnids with your class. If you have insect sample kits, that's great, but I've included dozens of clipart images of insects and arachnids to help get you started. You might also want to catch a few live ones in sample jars with magnifying glasses.
The first page explains some of the major traits and characteristics of insects and archnids to search for. The second page has places to sketch and answer questions about three different bugs or arachnids. Then there are 7 pages of images to look at. A second copy could be sent home with them if you have them do the first one in teams of 2-4 students.
Great KAGAN exercise in science!