mantis vs mantid

mantis and mantid both are nouns.

Word	Noun	Adjective	Verb	Adverb
mantis	Yes	No	No	No
mantid	Yes	No	No	No

As nouns, mantis and mantid are synonyms defined as:

mantis and mantid: predacious long-bodied large-eyed insect of warm regions; rests with forelimbs raised as in prayer

mantis (noun)	mantid (noun)
predacious long-bodied large-eyed insect of warm regions; rests with forelimbs raised as in prayer	predacious long-bodied large-eyed insect of warm regions; rests with forelimbs raised as in prayer