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.

In fact, insect vectors of Chagas disease parasites are "true bugs," of the order Hemiptera, family Reduviidae, subfamily Triatominae.