Lynn Poole explains the etymology of entomology, the study or science of insects and displays pamphlets produced by the U. S. Dept. of Agriculture. Mr. Hall, from the Agriculture Research Service, discusses the diversity of color, size, activity, and scope of insect species, which make up about three-quarters of the world's non-human species. He notes that beneficial insects offset the enemy insects; however, the latter can wreak havoc. Mr. Poole mentions Sir William Osler's malaria research linking the disease to mosquitoes and current prevention efforts for this and other mosquito-related problems. Mr. Hall explains how houseflies breed and how our health depends on controlling them, but he singles out grasshoppers as being particularly destructive. A film documents grasshoppers' reproduction and their natural enemies. Other destructive insects are clothes moths, silverfish, termites, and tree-killing insects. Means to control insect damage include insecticides, such as DDT, presumed safe and effective at that time.

Dr. Dethier explains his research for the perfect insect repellent. He discusses and gives examples of the five qualities of a perfect repellent: odorless, inexpensive, non-toxic, cosmetically acceptable, and effective for extended periods of time. Using a diagram of a blowfly's anatomy, Dr. Dethier explains how the flies are used in repellent research. Then using a series of actual flies, their wings waxed to sticks, Dr. Dethier puts the feet of the fly successively into sugar water, .01% glycol and sugar, and .1% glycol and sugar to observe the fly's reaction. The result is generally the average of a 100-fly test. Dr. Dethier then shows how one can predict the feasibility of some chemical compounds as repellents by their composition. He constructs a graph and using aldehydes, plots the repellent effect in relation to the size of the compound's molecules.

Many different species of insects and animals can be found in your own backyard. Charles Kolb shows live specimens of these species: turtles, lady beetles, aphids, grasshoppers, Japanese beetles, pill bugs, earthworms, spiders, toads, and snakes.