Matt Grobert ties the Zelon Midge a bit different from the original pattern as he notes here. The main difference is the use of Australian Opossum for the thorax and little bit less Zelon in both the trailing shuck and wing.
Zelon Midge Material List
Hook: Dai-Riki #125 (emerger hook), Size 20
Thread/Body: Danville 6/0, Olive
Thorax: Australian Opossum, Black
Wing/Shuck: Straight Zelon, Midge Gray