The 6 Kinds of Useful Insects (D 424) is a classified science set designed for Lower Elementary, focusing on insects that contribute positively to ecosystems, pollination, and human agriculture. Like its companion set D 425, it includes materials that support research, classification, and discussion of how living organisms interact within broader natural systems. This is a practical resource for teachers facilitating biology extensions or student-led inquiry into entomology and environmental interdependence.