Like some other popular nomenclature, Sulphur actually covers an umbrella of hatches, and more than just one species. Further it varies from location to location. But there are some generalities we can start with. First off Sulphurs are a mayfly hatching primarily, but not always in spring. It is an east coast native, and drives fish and fishermen wild. For simplification sake, we will cover three popular hatches; however there are many more minor hatches.


There is the big sulphur, or for the amateur entomologist, the Invaria. This beautiful bug puts up with a lot of human caused stream degradations and keeps putting out numbers that get our fly fishing hearts racing.


The Big Sulphur hatches usually begin in May and run for a good month. Appearing near the end of the Hendrickson hatch, and often confused with female Hendricksons. This hatch can be THE dry fly action of the year.



The Little Sulphur emergers a few weeks later, also known as the Pale Evening Dun, it actually is related to the west’s Pale Morning Dun. These hatches can occur simultaneously with Big Sulphurs, and can hatch all summer long on the same river, making them a favorite summer fly.



It is important to note that coloring variations are common, and can change day to day on the same river. Spinner colors fade to almost tan. But pale yellow and sulphur orange make good imitations of the varying shades. The Big Sulphur runs from 12-16, while the Little Sulphur runs 16-18. It is not as important to know exactly what is on the water, as it is to closely match the size, when in doubt go smaller.

There are other hatches commonly rolled into the ‘Sulphur’ moniker. Pink Cahills also emerge during May and can be seen throughout the summer. Appearing first up to size 12 and then by late summer they have downsized to 16.



Unlike the classic Sulphurs these don’t swim to the surface as emergers. But emerge fully developed like the Quill Gordon, adding to their importance as a good dry fly hatch. Unlike the Big Sulphur, Pink Cahills need almost perfect conditions for them to thrive. The male of the species does not share the pink abdomen, and is better imitated with a pale olive thorax.



There are other smaller hatches that are often lumped into Sulphurs and depending on location vary in importance. A good selection of Sulphur, Pink, and tannish colored flies will keep you in the game, and don’t forget the spinner and emerger stage as well. All stages can be the focus of fish, and times fish can be stubbornly myopic, only hitting one stage of the hatch at a time.