I'm from PA so I don't know exactly what insects hatch in Virginia, but I imagine they're pretty similar. There are far, far too many insects to list here. Some really good books on the topic would be:
"Eastern Fly Hatches" by Tom Fuller
"The Orvis Streamside Guide to Trout Stream Instects" by Dick Probst
"Hatches II" by Al Caucci and Bob Nastasi
"Caddisflies" by Gary Lafontaine
"Art Flick's Streamside Guide" by Art Flick, of course
All of these are wonderful books, with the Orvis book and Art Flick book being the least "technical" and both Hatches II and Gary Lafontaine's "Caddisflies" both providing more than enough information on the subjects of entomology, both being quite "epic" in length. Hope this helps.
-Darryl
My one wish is that when I die my wife doesn't sell my fishing stuff for what I told her I paid for it...