The gonapophyses are the projections near the extremity of the body that surround the sexual orifices, and vary extremely according to the kind of insect.
The development of the armature has been little studied, and the question whether there may be present gonapophyses homologous with those of the female is open.
Whether cerci, stylets and gonapophyses are developed from these rudiments has been much debated.
It appears that it is possible to accept cerci and stylets as modifications of the temporary pseudopods, but it is more difficult to believe that this is the case with the gonapophyses, for they apparently commence their development considerably later than cerci and stylets and only after the apparently complete disappearance of the embryonic pseudopods.
The fact that there are two pairs of gonapophyses on the ninth abdominal segment would be fatal to the view that they are in any way homologous with legs, were it not that there is some evidence that the division into two pairs is secondary and incomplete.
But another and apparently insuperable objection may be raised - that the appendages of the ninth segment are the stylets, and that the gonapophyses cannot therefore be appendicular.
The typical insectan ovipositor, so well developed among the Hymenoptera, consists of three pairs of processes (gonapophyses) two of which belong to the ninth abdominal segment and one to After C. Janet, Aiguillon de la Myrmica rubra (Paris, 18g8).