Millerbees "Hornet Funnels" are selective Hornet traps.  The entry hole is sized for Yellow legged Hornets and European Hornets.  The entry hole is small enough so many larger insects like silk moths etc. cannot enter.  Smaller holes in the funnel sides allow smaller insects like Honeybees to escape.  There are two sizes regular mouth and large mouth, these fit regular mason jars and most plastic mayo jars.  The large mouth fits mouth mason jars.  Bait is generally 1 part dark brown sugar and 2 parts grape juice.  There are many other recipes for bait.  Sticks or other flouting material may be added to allow nontarget insects to land on and escape.