MYAGRUS DEUS, in the heathen mythology, a name
sometimes given to Jupiter, and sometimes to Hercules,
on occasion of sacrifices being offered to them for driving
away the vast numbers of flies which infested the victims
on certain public occasions. The word is usually spelt
Myagrus; but this must be an error, as the word does not
express the "fly-destroyer," but the "mouse-destroyer,"
and it is sufficiently testified by the ancients, that flies
were the only creatures against whom this deity was in-
voked. Pliny calls this deity Myiodes, and tells us that
the flies which used to pester the Olympic rites went away
in clouds on the sacrificing of a bull to this god. We find
in Athenæus, also, that this sacrificing to the god of flies
at the Olympic games was a constant custom. Some au-
thors distinguish these two deities, and tell us that the lat-
ter, or Myiodes, used to visit the nations in vengeance with
a vast multitude of flies, and that, upon paying him the
due honours of a sacrifice, they all went away again; and
this seems to agree with what Pliny mentions in several
places. At the time of the Olympic games, Jupiter was
worshipped under the name of Apomynos or Myiagrus Deus,
and supplicated to effect the destruction of these trouble-
some creatures. This happened only once in many years,
when the sacrifices were performed there; but the Elians
worshipped him continually under this name, deprecating
the vengeance of heaven, which usually sent, towards the
latter end of summer (as they expressed it) an army of flies
and other insects, which infested the whole country with
sickness and pestilence.