Possible Clues:

• Kind of Dr.
• Initially one goes on ahead for work
• Suffix with despond
• Initially one gets ahead with one's speciality
• It's for the doctor to rap this so as to catch it
• Characterized by: Suffix
• Insect study: Abbr.
• Suffix with consist
• Otitis treater: Abbr.
• Treebeard, e.g.