Eggs found under sumac tree leaves

[acreemer]

I've noticed that my three year old sumac tree had some wilting yellow leaves, and some leaves that had curled. Previously the sumac has always been very healthy and hardy, so I was surprised and went in for a closer look.

The attached pictures show what I found, and what I am hoping you can help me to identify. There is definitely some sort of pest infestation, with brown/orange colored eggs. I also noticed some tiny flies with long wings flat to their backs, but I'm not sure if they are related to all of the eggs.

I've googled quite a bit this evening, but haven't found anything that really matches what I saw. Hope someone can help!