Just started SR4, and I'm looking to find out which books in previous editions have material on the insect spirits and ghouls. One of my players has been quite interested in them. Also, any that are peticularly chock full of plotline goodness.

(does the spell check work? I just get a black box. Grrr. Too tired to spell.)

insect spirits are slightly spread out across several books. i think they were in MitS though.

ghouls are either in critters (if you're looking to run them as NPCs) or SRComp (if your players want to play one, and don't mind sucking)

The Insect spirit/Universal Brotherhood story arc played out across several adventures and sourcebooks (Queen Euphoria, Universal Brotherhood/Missing Blood, Double Exposure, Bug City, the novel Burning Bright, Threats, Target: UCAS).

Other canon appearances include the novels 2XS and House of the Sun, and the Mantis/Penchyk arc which is featured in Super Tuesday and Shadows of the Underworld.

Rules were introduced in the Grimoires (SR1 and SR2), Awakenings (SR2), Magic in the Shadows (SR3) - though Street Magic (SR4) updates most of the previous rules material.

Bugs also get mentioned in a lot of location books from Target: Awakened Lands to Shadows of Europe to Loose Alliances