Insecta in the 10th edition of Systema Naturae

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

• Heart: 1 auricle, 0 ventricles. Cold, pus-like blood.
• Spiracles: lateral pores
• Jaw: lateral
• Penis: penetrates
• Organs of Sense: tongue, eyes, antennae on head, no brain, no ears, no nostrils
• Covering: a bony coat of mail
• Supports: feet, and in some, wings. Skips on dry ground and buzzes

Orders

Linnaeus divided the class Insecta into seven orders, based chiefly on the form of the wings. He also provided a key to the orders:

• 4 wings

• pairs dissimilar

• forewings fully hardened: Coleoptera
• forewings partly hardened: Hemiptera

• pairs similar

• wings covered with flat scales: Lepidoptera
• wings membranous

• Tail unarmed: Neuroptera
• Tail bearing a sting: Hymenoptera

• 2 wings: Diptera
• 0 wings: Aptera

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. Similarly, the sheep ked Hippobosca ovina (now Melophagus ovinus) was correctly placed among the Diptera, despite being wingless.