Possible Clues:

• Students may be searched for them in grade school
• Dog's woe
• "___ Capades" ("South Park" episode)
• Grade-schooler's woe
• Some ectoparasites
• Cause of some head scratching?
• How lousy to be frozen after half a century!
• Some creepy-crawlies
• Vermin's headcount 95 per cent reduced, but still vermin
• Pediculicide's target