long-horned beetle vs longicorn beetle

long-horned beetle and longicorn beetle both are nouns.

Word	Noun	Adjective	Verb	Adverb
long-horned beetle	Yes	No	No	No
longicorn beetle	Yes	No	No	No

As nouns, long-horned beetle and longicorn beetle are synonyms defined as:

long-horned beetle and longicorn beetle: long-bodied beetle having very long antennae

Other synonyms of long-horned beetle include longicorn.

long-horned beetle (noun)	longicorn beetle (noun)
long-bodied beetle having very long antennae	long-bodied beetle having very long antennae