Then there's this line, which Enobarbus comes out with when he and Agrippa are making fun of Lepidus and his ineffectual relations with Caesar and Antony: "They are his shards and he their beetle" (3.2.20).
Arden's note reads:
An allusion to the proverb "The beetle flies over many sweet flowers and lights in a cowshard" (Tilley, B221). Steevens and others mistakenly interpreted shards as "the wings of a beetle" owing to a misunderstanding of Mac 3.3.42, "the shard-born beetle" ("shard-borne" in F) which actually means "the beetle born out of dung". A shard is a cow-pat (OED sb2).
Now, I'd always thought of "shard" as meaning beetle wings, but of course I might have been misled by Steevens and his successors. The OED does have that sense too, but its earliest citation is 1811 - except for a bracketed citation from Johnson's Dictionary (1755), which reads, under the entry for "Shardborn": "Perhaps shard in Shakespeare may signify the sheaths of the wings of insects."
Of course, the OED's earliest citation is just that - it doesn't tell us when a sense came into use. So, what is Johnson going on here? Perhaps this is an informed guess - after all, he and Shakespeare were both Midland boys (Lichfield is just 44 miles from Stratford), and there may be some dialect word for beetle wings that they both knew, of which the OED is ignorant. He doesn't sound very certain, though: perhaps he was flailing about for a reading and, inspired by F's "borne", looking for something that keeps beetles aloft rather than something that hatches them?
Okay then, what about internal sense? The image of the lumpen Lepidus (who had to be carried out drunk a few minutes earlier) being the heavy beetle borne up by the glistening wings of Antony and Caesar makes perfect sense to me. On the other hand, though our editor doesn't mention it, the idea of beetles being born from dung does evoke thoughts of scarabs, and is just the kind of Egyptian detail Shakespeare scatters throughout the play. But I don't see how it works as a metaphor: it would require us to think of Antony and Caesar as dung, which seems a very unlikely image even for the irreverent Enobarbus. The explanation through Tilley's proverb has the same problem. For that matter, why would a beetle require more than one shard from which to be born?
In short, the editor has succeeded in robbing me of confidence in a rather striking and effective image, but failed to offer a replacement that works. Blast you, John Wilders!