could be wrong, but looking again at the thickness of this glass I'd suggest it's far too thin to accommodate real cutting i.e. the sort of deep mitres which adorn thicker pieces such as decanters and vases etc., so wheel engraving it is - at least that's the standard description in the U.K., although appreciate this is one of those descriptions that varies depending on your whereabouts on the globe (with apologies to Ken:) )
Talented glass artists can create toned images by wheel engraving, which will show both matt and shiny areas in close proximity on the same piece, whereas it's rare to get anything other than shiny polished decoration on traditional on cut glass.
Typically, acid etching will show, usually, as being more shallow than wheel engraving, and then again real cutting will be deeper than both, and probably true to say that acid work will show less freehand style than wheel engraving. Normally, it shouldn't be possible to confuse deep hand cutting with either of the other forms of decoration.
In most artistic media, images are stylized - that's really the whole point of art (might have been Picasso who said - "all art is a lie?) - if you want reality then buy a camera - and these insects are good examples of stylization - in other words they almost certainly don't represent particular species, but are a sufficient approximation to convince us they are a butterfly/moth type insect.
Always a little embarrassing to be caught out when trying to be too clever ........... technically butterflies do have club tips to their antennae, but then again so do some day flying moths

The same effect is probably applied to flowers, although there may be a little more intended accuracy with images of flora.
I agree, I think it's a great piece - hand blown, hand engraved, and attractive. Regret can't help remotely with States or Continental Europe glass engravers, and there seem to have been few British workers who have signed their wheel engraved work - regarding earlier pieces, both Jack Lloyd and William Fritshe sometimes did - try the Board's search and you'll certainly find info. on Lloyd at least, and examples of his work.
just enjoy the artistry, and buying this you've now learned some more about glass - on the other hand you may now be as confused as the rest of us
