Random fact, I know, but there are a great deal of species of snakes (especially larger snakes or ones that live in colder climates) that actually birth live young like a mammal does, or which use eggs, but carry those eggs in their body until the time they hatch.
Since the lamia is supposed to be more human than a standard serpent, the parcity of lamia oviposition comparable to harpy oviposition may be better-justified than one may think.
