Related Clues:
- Immature creature right in middle of molten rock
- Hot rock on the radio for an immature type?
- Young insect
- Intermediate stage completed after being put back a year
- Caterpillar or tadpole, eg
- Insect at early stage of development
- Undeveloped creature right inside molten rock
- Immature 13, say, at university in Pennsylvania
- Immature creature picked up from volcanic discharge
- Phase for many insects