In the Jurassic period many of the existing families, such as the Cicadidae, Fulgoridae, Aphidae, Nepidae, Reduviidae, Hydrometridae, Lygaeidae and Coreidae, had already become differentiated.

The Coreidae have a smaller scutellum, and the feelers are inserted high on the head, while in the Lygaeidae they are inserted lower down.