Thanks for the responses. I saw no exit holes, and Powder Post Beetles produce a dry dust from my experience. Fungus fits, or some sort of wood destroying organism. I feel like I've seen this before, so maybe your wood pile scenario works. My larger concern is; in this 70+ year old home, why is this happening now? The current tenant states that she has never had water in the basement in the last seven years. Regardless, the basement was very wet...smelled like mold, and note the 84% on my moisture meter !!!!