Abstract In Plodia interpunctella, Ephestia cautella, Anagasta kuehniella, and Sitotroga cerealella the bulla seminalis is the site where ova are degenerated after females are 24–28 hr old. When ova are shunted into the bulla seminalis and massaged by muscular contractions the chorions gradually weaken and rupture. Empty chorions are compressed into a pellet and remain in the bulla. The number of ruptured eggs varies between species. Mated females in P. interpunctella and E. cautella, degenerate more ova than virgin females. Degeneration of ova in the bulla seminalis may be a means of extra-ovariolar resorption that leaves the oviducts unobstructed so oviposition can occur. The process may be a faster means of freeing yolk from the ova than the digestion of the chorion that is characteristic of oösorption in other insects. In the four species studied, the bulla seminalis which also acts as a pump in the transfer of sperm from the bursa copulatrix to the spermatheca, thus has a dual function.