On The Wrong Trek is a 1936 short film starring Charley Chase, directed by Harold Law, produced by Hal Roach and distributed by MGM. It features a cameo appearance by Laurel and Hardy.
At the start of the journey they consider taking on hitchhikers and see Stan and Oliver on the side of the road thumbing a lift both, however, are thumbing in opposite directions until Hardy notices, slapping Laurel. Oliver is sitting on some luggage and Stan is standing, holding an umbrella. Charley remarks that they look like horse thieves, drives by and scratches the top of his head in the same way that Stan does in all of his films. They appear on screen forseconds.
Source: Wikipedia