In case it helps my Lamia Rules:
Serpents Child (Ranged, permanent if successful, the spell takes 2D6 hours to perform)
Lamia are not born but rather created through the use of this spell. In order to perform the ritual, the caster requires the target (a willing humanoid female) and a snake of equal SIZ. The two are combined in the first part of the spell - which takes D6 hours and they both become a single egg like entity - this must then be fed (it absorbs it through the shell) blood (STR points) equal to the SIZ of the two now combined target creatures. After a further D6 hours, the newly born Lamia will emerge, ravenous for blood - she counts as being desiccated. The humanoids stats and skills remain the same with the exception of her SIZ which is doubled and any derived stats that depend on SIZ. She gains a bite and constrict attack at her basic melee or unarmed skill - whichever is greater as well as the ability to drain POW with her Kiss.
Bite: A Lamia may attempt to bite a willing victim, or an unwilling one if she grapples him first, she can then drain blood in the same way as a Vampire. She can drain 1pt of STR per CA, which given food and rest, the victim can recover at the rate of 1pt per hour. However if the victim is drained below half their normal STR, they recover 1D6 STR pts per day but only if given food and complete rest.
Kiss: A Lamia may attempt to kiss a willing victim, or an unwilling one if she grapples him first. She can then drain 1pt of POW per CA, which given complete rest, the victim can recover at the rate of 1pt per hour. Each POW point she drains gives her an additional magic point which can not take her over her normal maximum but can temporarily replace those being used for powering Runes or similar.
Sustained by Blood: A Lamia requires blood to live and needs at least (preferably more) blood (or STR pts) equal to her SIZ each week or she will begin to desiccate. Desiccation will mean she looses 1 from each of her attributes every day until she receives enough blood to revive her - which is equal to at least twice her CON.