backswimmer vs Notonecta undulata

backswimmer and Notonecta undulata both are nouns.

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

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

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

backswimmer (noun)	Notonecta undulata (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