Smaller appendages (such as the stylets of male cockroaches) may be carried on the ninth segment.
- 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.
In generalized biting insects, such as cockroaches and locusts (Orthoptera), the parts of a typical maxilla can be easily recognized in the labium.
3, d), which is large and conspicuous in those insects, such as cockroaches, bugs (Heteroptera) and beetles, which have the prothorax free - i.e.