I can't remember where or when I read it, and it was probably not a magazine.
Begins with a spaceship with the solo survivors from a planet and follows their flight to Earth.
They arrive safely and prepare to meet the inhabitants and open their ship.......
And the housewife screams and whips out the fly spray ........ and they all die . Turns out they are very small.
Anne
[Found] Looking for a ?science fiction story I once read
Could it be 'Meteor' by John Wyndham?
http://ayapasuprep.weebly.com/uploads/2/1/9/6/21967966/wyndham-meteor.pdf
http://ayapasuprep.weebly.com/uploads/2/1/9/6/21967966/wyndham-meteor.pdf