Fabrice mentioned the green caterpillar primitive here:

http://kanji.koohii.com/study.php?framenum=835

There seem to be no kanji that solely correspond to green caterpillar. But I was wondering if green caterpillar shows up in any other kanji? Quickly glancing at the upcoming kanji, I don't find the primitive again...

edict shows 10 kanji with the green caterpillar

KANJIDIC (1 entry)

蜀 (虫) ショク, ゾク, いもむし green caterpillar, Szechwan

e.g.

燭 (火) ソク, ショク, ともしび
light, candlepower 2539

獨 (犬) ドク, トク, ひと.り
alone, spontaneously, Germany (non-Heisig)

獨 is actually the old form for 独 and 觸 is the old form for 触. 囑 and 屬 are old forms for 嘱 and 属, respectively (both RTK1 kanji). After that, 燭 and 濁 are Heisig kanji and the remaining 4 (蜀, 髑, 躅, and 矚) are not old forms of anything else.

[ファブリス]

Oh, thanks for that very informative post, JimmySeal.

So there are only two RTK kanji which use 蜀 as a primitive.

Also, the compound for "green caterpillar" doesn't use the (older?) kanji anyway :
芋虫 【いもむし】 green caterpillars

I didn't know about the old forms back then, so it seemed worthwhile to learn the "green caterpillar" kanji 蜀 and then use it as a primitive, even though the "green caterpillar" kanji itself is not part of RTK.

Seeing the spots on the green caterpillar's back as "eyes" helped me remember the primitive easily :



However even though a "rope-like insect" seems to make sense, it's just a coincidence, as Heisig's squashed eye 罒 is a compressed form of 网 which is a radical for "a net" (interwoven ropes). I found it helpful to create a separate image for that primitive, such as a "cyclop's eye" because in some occasions it was not easy to deduce whether the "eye" primitive should appear on the left or on the top.