I find the the "Biodiversity Heritage Library" links & interface for the catalog easier to work with than those of the "Internet Achive"...in particular for providing clean reference links to pages of interest when writing up remarks or comments for BugGuide (though perhaps it's a "6 of one, half-a-dozen of the other" kinda thing).

Links to the BHL pages appear below:

  Volume 1: Symphyta and Apocrita (Parasitica)
  Volume 2: Apocrita (Aculeata)
  Volume 3: Indices

Though it's nearly 40 years old now, I've found this magnificent tome by Krombein & Co. (AKA "The Red Book") to be extremely useful in getting a feel for Hymenoptera...in terms of its organization, and the vast numbers of taxa at various levels. And also, importantly, for ferreting out more specific and detailed reference papers in the literature!!