The third or outermost chamber, the proctodaeum, is closed externally by the sphincter ani; the orifice is quite circular.
The penis, and its much reduced vestige of the female, is developed from the ventral wall of the proctodaeum.
In some parasitic Hymenoptera there is only a single the proctodaeum respectively.
extremity of the stomadaeum and of the proctodaeum.
that portion of the gut which is formed by the hypoblast, whereas in Hexapod insects the similar caecal tubes are developed from the proctodaeum or in -pushed portion of the gut which is formed from epiblast.