anyone know what they are or how to do them?
go to youtube and do a search
prone cobra is like lying on an incline bench, belly down so your arms hang below the bench, and doing curls with a reverse grip. killer forearm exercise.
prone trap raises just means hands in pronated grip (overhand).
These are scapular stability exercises, not forearm/biceps movements. For prone cobras, check out the prescription at http://www.T-Nation.com/readArticle.do?id=459846
Prone trap raises:
"**Prone position mid trap raises
Lie prone (on your belly) using an incline bench set at 45-degree. Grip two dumbbells with the thumbs up (like in a hammer curl). Keeping arms straight, elbows slightly bent, raise the dumbbells toward the ceiling to form a 90-degree angle with your neck. (The 3 and 9 positions of a clock). Retract your shoulder blades (squeeze them together) at the top position. "