- Outline of Male (a') and Female (?) Cockroaches (Blatta) from the side, showing Abdominal Segments (numbered I-b).
In the Mesozoic rocks (Trias and Lias) there have been discovered remains of insects intermediate between those ancient forms and our modern cockroaches, the differentiation between forewings and hindwings having begun.
Smaller appendages (such as the stylets of male cockroaches) may be carried on the ninth segment.
Cockroaches are nocturnal creatures, secreting themselves in chinks and crevices about houses, issuing from their retreats when the lights are extinguished, and moving about with extraordinary rapidity in search of food.
In generalized biting insects, such as cockroaches and locusts (Orthoptera), the parts of a typical maxilla can be easily recognized in the labium.