Notonecta undulata vs backswimmer

Notonecta undulata and backswimmer both are nouns.

Word	Noun	Adjective	Verb	Adverb
Notonecta undulata	Yes	No	No	No
backswimmer	Yes	No	No	No

As nouns, Notonecta undulata and backswimmer are synonyms defined as:

Notonecta undulata and backswimmer: predaceous aquatic insect that swims on its back and may inflict painful bites

Notonecta undulata (noun)	backswimmer (noun)
predaceous aquatic insect that swims on its back and may inflict painful bites	predaceous aquatic insect that swims on its back and may inflict painful bites