I posted an article on the PA Trout Streams page that has some hatch info. It is hardly a comprehensive list but it could be helpful.
Muddy Creek Article
Muddy Creek is no bug factory but it does have enough to keep it from the 303d list of impaired streams.
Winter thru March provides pretty good lil' black stoneflys then from march thru april you could run into a few darker mayfys but not many. THe sulfurs can be pretty good in late may early june but by then the water is warming and you catch alot of chubs with a few trout mixed in. There are cahills too in summer and fall has pretty good Slate drakes. Caddis work all the time when fish are rising.
The thing about Muddy Creek is that there are not robust populations of stocked trout and you have to cover alot of water to find cooperative fish. There is alot of "dead" water more suitable for bass than trout. You will run into some wild fish that are likely transition fish from tributaries, again, in the best lies.
Muddy Creek is really a good test of your ability to read water. Some years certain named sections or holes are very productive, others not so depending on what the last flood has done to the creek.
Back to the hatches, I personally do not fish drys there unless I see rising fish. Except in the Fall when searching with a slate drake has been proven productive.
Run into a good hatch of caddis, a sulfur spinner fall or the slates and lb stones and you can feel like you are on a great trout stream and tomorrow get skunked there.
I like early season streamer fishing there, buggers for covering water to find fish and banging big golden or black stoneflies (perlas) in the fast pocket water.
Man ya got me whet now...I may have to go fishin'
Maurice