With very few exceptions, the larva in this group is active and campodeiform, with cerci and elongate legs as in the Adephaga, but the leg has only four segments and one claw.
C. Bdrner (1904), for example, considers the presence or absence of cerci of great importance, while F.
In the vast majority of the Dermaptera the cerci are - in the adult insect at least - stout, unjointed appendages forming a strong forceps (fig.
The carabid larva is an active well-armoured grub with the legs and cerci variable in length.
The eleventh abdominal segment which carries the short jointed cerci (fig.
As regards wing-structure, the Isoptera with the two pairs closely similar are the most primitive of all winged insects; while in the paired mesodermal genital ducts, the elongate cerci and the conspicuous maxillulae of their larvae the Ephemeroptera retain notable ancestral characters.
The cerci are nearly always joined, and a typical insectan ovipositor with its three pairs of processes is present in connexion with the vagina of the female.
Jointed cerci always present; ovipositor well developed.
The Mecaptera, with their predominantly longitudinal wing-nervuration, serve as a link between the Neuroptera and the Trichoptera, their retention of small cerci being an archaic character which stamps them as synthetic in type, but does not necessarily remove them from orders which agree with them in most points of structure but which have lost the cerci.
Short cerci, and the Pelobiidae, which have elongate larvae, tapering to the tail end, where are long paired cerci and a median process, recalling the grub of a Mayfly.