Signature Tyer Paul Procter shares the tying instructions for his famous All Purpose Terrestrial (APT) dry fly. This is an excellent summertime dry fly no matter where you fish because it's designed to be suggestive of many different types of terrestrials. For example, in sizes 14-16 it can be taken as a black gnat, in sizes 16-18 it can be taken as an ant, and, because of the glint in the body, it can be taken as a beetle in most sizes. You just have to match the size to the terrestrials you see on the water you're fishing. Truly, this is a pattern we would not be without when fishing for trout in the summer.