What is this?

[JAG]

Tom,
MD83Driver posted a great link. The airspeed switch on your '67 is pure genius, as it is meant to actuate at an airspeed right around take off, giving you the most accurate tach time to correctly log all your air time for airframe and engines. However, it looks like yours might be modified a little and may actuate in a strong breeze, if not cause some drag! I have attached a picture of what one looks like - the actuator paddle should trail, and when it actuates, it rests up against that little button on the lower wing skin.
Jeff