Right Word and Almost Right Word

“The difference between the almost right word and the right word is really a large matter — ’tis the difference between the lightning-bug and the lightning” (Mark Twain).
 I would have written “lightning BOLT” for alliterative purposes — so, BUG and BOLT. Mark Twain fain broke off the “bolt” when he should have wrote:
“’tis the difference between the lightning-BUG and the lightning BOLT.”
But alas. So is Twain’s blazing-across-the-stormy-night-sky omission of “BOLT” a lightning bug? And is my revision of “BOLT” therefore a lightning BOLT? Or am I just lost in a haze or in an over-analytic gaze since Twain speaks of word while I speaketh of phrase?