This issue is a variant of Zap Comix (Apex Novelties, 1967 series) #0. There exist further variants.
Early printings by Apex Novelties. Later printings by Print Mint and Last Gasp with the Apex Novelty logo still on the cover.
Underground Comix are known for using different prices, covers (art or color variations) and/or interior content to distinguish between printings.
1st-5th prints have 0.35 USD cover price.
1st has hairline mark in Z on front cover. Pages numbered upper right in interior.
2nd has no hairline mark or page numbers.
3rd-5th have scratches and retouching to guy's spine on cover.
6th print has 0.50 USD cover. 7th print has 0.60 USD cover. 8th print has 0.75 USD cover.
9th print has 1.50 USD cover. 10th print has 2.50 USD cover. 11th print has 2.95 USD cover.
12th? print has 3.95 USD cover. 13th print has 4.95 USD cover.
First edition is known to exist as untrimmed, with a 1/4-inch white bar around 3 sides that was never trimmed.
As stated in Mark James Estren's "A History of Underground Comics," this was actually published after Zap #2 came out in 1968. The artwork for this issue was lost after the publisher who had it moved to India. Luckily, Crumb had made xeroxes which he managed to locate months later. Crumb did get the original artwork back several years later.
Sequence is on inside front cover. This page is signed by Crumb at the bottom and dated October 1967.
Yarrowstalks was a Philadelphia underground tabloid.
This originally was a Crumb sketchbook strip from 1967
Sequence on inside back cover.
This is reprinted twice in the Complete Crumb vol. 4., once in b&w, once in color.