Beetles have two pairs of wings, but only use one for flying, as the exterior pair is hard and only used for protection against predators. Several beetles species are found in Illinois, including the tiger beetle (Cicindela hirticollis), the Asian lady beetle (Harmonia axyridis), as well as the spotted and striped cucumber beetle and the invasive Japanese beetle, which are agricultural plagues. Lepidoptera include moths and butterflies. More than 280 species live in Illinois, including the zebra swallowtail with a wingspan of 4 inches, the bright-orange American copper and the monarch. The spur-throated and the green-striped grasshoppers are some members of the order Orthoptera living in Illinois.
Part of the order Odonata, dragonflies and damselflies living in Illinois include more than 90 species, including the American rubyspot, the slender spreadwing, the powdered dancer, the horned clubtail and the calico pennant. Ephemeroptera or mayflies are abundant in Illinois. Common genera in the state include Plauditus, Pseudocloeon, Pseudocloeon, Ephemerella, Stenonema and Isonychia. Members of the order Mantodea, praying-mantids living in Illinois include members of the genera Tenodera and Stagmomantis.
Diptera includes all insects with a single pair of wings, such as mosquitoes and flies, while Hymenoptera refers to wasps, bees and ants. Species living in Illinois include the yellow jackets of the genera Vespula and Paravespula, bumblebees of the genus Bombus, hornets Dolichovespula and the carpenter ant Camponotus. Among Diptera, drosophila flies and mosquitoes of the genus Aedes are some examples of Illinois insects. Psocoptera refers to booklice or barklice,flying insects often smaller than 0.4 inches. Trogium and Lepinotus are genera found in Illinois.
Blattaria include all wild and domestic cockroaches, such as the American cockroach (Periplaneta Americana), also found in Illinois. Aphids are small plant-sucking insects and agricultural plagues, part of the order Hemiptera. In Illinois, common aphids include members of the genera Aphis, which attack soy and other food crops. Isoptera are termites, which also have representatives in Illinois, including Reticulitermes and Heterotermes.
Firebrats and silverfish are part of the order Thysanura, while thunderflies, corn lice or thrips are insects members of the order Thysanoptera. Common species living in Illinois include the common silverfish (Lepisma saccharina), the firebrat Thermobia, and thrips of the genera Sericothrips and Frankliniella, which are agricultural plagues. Phthiraptera are lice, with more than 3,000 species around the world, most of them parasites. Sucking lice or Anoplura and chewing lice Amblycera are found in North America, including Illinois.