In the 10th edition of Systema Naturae of 1758–1759, Carl Linnaeus classified the arthropods, including insects, arachnids and crustaceans, among his class "Insecta".
He described the Insecta as:[1] A very numerous and various class consisting of small animals, breathing through lateral spiracles, armed on all sides with a bony skin, or covered with hair; furnished with many feet, and moveable antennae (or horns), which project from the head, and are the probable instruments of sensation.Linnaean Characteristics[1] Linnaeus divided the class Insecta into seven orders, based chiefly on the form of the wings.
He also provided a key to the orders:[2] Despite this key, however, Linnaeus grouped insects together that shared other affinities.
His genus Coccus, containing the scale insects, he placed among the 4-winged Hemiptera, along with aphids and other plant-attacking insects, even though females have no wings, and males have two wings.
[2] Similarly, the sheep ked Hippobosca ovina (now Melophagus ovinus) was correctly placed among the Diptera, despite being wingless.