sandfly vs sand fly

sandfly and sand fly both are nouns.

Word	Noun	Adjective	Verb	Adverb
sandfly	Yes	No	No	No
sand fly	Yes	No	No	No

As nouns, sandfly and sand fly are synonyms defined as:

sandfly and sand fly: any of various small dipterous flies; bloodsucking females can transmit sandfly fever and leishmaniasis

Other synonyms of sandfly include Phlebotomus papatasii.

sandfly (noun)	sand fly (noun)
any of various small dipterous flies; bloodsucking females can transmit sandfly fever and leishmaniasis	any of various small dipterous flies; bloodsucking females can transmit sandfly fever and leishmaniasis