it means like wider...then there eyes....like the abdoman of that moth is prolly no bigger then they space between his eyes...people break this rule alot with hornworms....w/e its you decision in the end.
Squishy things can be fed if they're slightly larger than their eyes. I've seen my veiled wolf down a rather large dubia though... He didn't choke though it did take him a while. I just try not to because it's scary to watch and scary to think about them choking...
always keep in mind your chams jaw strength! and yea i broke that rule the first time i saw a hornworm in moth form in my version, godzilla beat mothra.
ooh was that a mantis?