Peripodal cavities: pouches in the embryo in which the rudiments of the future legs and wings are developed.

Peripodal membrane: the cell layer surrounding the peripodal cavities. Peristaltic: that periodic motion of the alimentary canal by means of which the food is forced toward the anal extremity.

Peristethium: the meso-sternum.

Peristoma -ium: the border of the mouth or oral margin in Diptera; sometimes used as := epistoma: q.v.

Peristome: a membranous tissue surrounding the mouth parts at base, and forming the true ventral wall of the head.

Peritoneal: applied to the membrane surrounding the viscera, trachea, and other internal structures.

Peritracheal: surrounding the trachea.

Peritreme: the corneous selerite surrounding a spiracle.

Peritrophic membrane: a funnel-like extension of the fore-gut, extending back tube-like, through the chylific ventricle in some insects.

Perivisceral: the cavity containing the alimentary canal and its appendages.