In "
Ritual Embodiment in Modern Western Magic: Becoming the Magician", scholar Damon Zacharias Lycourinos describes some rituals he witnessed personally. In the chapter "The Apollinian Invocation" (PGM I. 262–347), he writes on p. 96:
Instead of the lamp requested in the spell, he dug a deep fire pit due to the rationale that he was to daimon of Hades with the fire pit being a representation of the river Phlegethon – a river of fire that coils round the earth and flows into the depths of the underworld. For an altar he used some flat sea rocks instead of the head of a wolf, but the Theurgist had constructed a small wolf’s head from clay to at least represent the correspondence to Apollo as slayer of wolves.
I think I've read about this modern custom to substitute animal sacrifices with clay figurines before, and I'm not sure some recipes calling for live ingredients weren't in fact blinds anyway, such as the very first spell in the Betz translation requiring the killing and mummification of a falcon - there's a story where a Roman legionnaire in Egypt killed an animal sacred to a god by mistake, and the angry crowd just tore him to pieces. Obtaining a live falcon was and is hard enough, killing it difficult what with that these talons and the sharp beak, and if anybody found out in those times… it's interesting though that he replaced the lamp (which would have been readily available) with a firepit, it must mean that he was very confident his ritual would work anyway and probably felt that it just made more sense to him, so you have your correspondence (lamp => river Phlegethon => fire) right there. Perhaps you could take some graveyard dirt (most authors insist showing respect to the spirits by leaving a small payment!) instead of that strip of cloth; coffin nails are probably equally hard to obtain.
There was a forum thread once where a member asked a similar question about substitutions, this time a grimoire spell calling for mole blood. I suggested beetroots because they grow underground, just like moles living underground, and their juice is blood-red.
So Apollo was known as a slayer of wolves, and the ritualist was well aware of the correct correspondences, sticking to the wolf head's ingredient, if only symbolically.
