Cockroaches are popularly thought to be an ancient order of insects, with their origins in the Carboniferous.

[7] The youngest known roachoids date to the Cretaceous, by which time they were rare compared to modern cockroaches.

[8] The fossils assigned to the "roachoids" are of general cockroach-like build, with a large disc-like pronotum covering most of the head, long antennae, legs built for running, flattened body and heavily veined wings with the distinct arched CuP-vein so typical of modern cockroach wings.

[9] Like modern cockroaches, the roachids were probably swift litter inhabitants living on a wide range of dead plant and animal matter.

The egg pods, called ootheca, seen in modern dictyopterans is a new shared trait (synapomorphy) separating them from their primitive ancestors.