I got to sing Sam Hinton's version of this at this past Earth Day fest locally. I was surprised at how well the adults did. Here's one additional verse plus one extra word for another verse.

One lissome lass had a loathsome lisp
And the other lissome lass lisped less.

One big black bug bled blue-black blood
And the other big bug bled blue;


which is very close to a classic short toughie

Black bat's blood.