Maybe it is Meteor by John Wyndham. It was written in 1941 but was published 1956 in The seeds of time.
It matches the style and description somewhat. Meteor is about a race of tiny aliens, though they are benevolent and not conquering, that land in a garden. When the humans find them they think they are bugs, and when the aliens defend themselves the humans think they have been stung. It ends with the aliens dying, though it is from bug spray and not being stomped on
An alien spaceship lands on Earth possibly with the intention of
We must have arrived on that beautiful, shining blue planet, with Forta only a tiny light in our new heavens. I feel full of hope. Until now, my life has been spent on a dying planet. Here, there is a world to build and a future to build for. I can hear our machines at work, opening the long passage which had been filled for the journey. What shall we find, I wonder? What ever this world is like, we must not betray our trust. We each possess a million years of history, and a million years of knowledge. All this must be preserved.
This planet is very young, and if we do find intelligent life, it will be only at its beginning. We must find them and make friends with them. They may be very different from us, but we must remember that this is their world. It would be very wicked to hurt any kind of life on its own planet. If we find any such life, our duty is to teach, and to learn, and to work with them.
Unfortunately they have miscalculated. They assumed that we were the same size as them.
Someone comes along and, mistaking their tiny space-ship for some weird kind of beetle,
Oh, poor Mitty, Sally said. I think she’s dead!
She went down on her knees beside the dog’s body.
She is dead! she said. I wonder what She suddenly stood up, put her hand to her leg, and held it tight. Oh, something has stung me. Oh, it hurts. There were tears of pain in her eyes as she rubbed her leg.
What on earth−? began her father, looking down at the dog. What are all those things? Ants?
Graham bent down to look.
No, they’re not ants, he said. I don’t know what they are.
He picked up one of the tiny creatures to look at it more closely.
It was a strange−looking little thing. Its body was an almost perfect half of a ball, with the flat side underneath. The round top was pink and shiny. It was like an insect, except that it had only four legs, which were very short. It had no separate head, but it had two eyes on the edge where the curved top of its body met the bottom.
steps on it and squashes them.
Hell! he exclaimed, shaking the creature off his hand. The little horrors certainly can sting. I don’t know what they are, but they’re dangerous things to have in the garden or the house. Have you got any insect−killer?
Yes. There’s a tin in the kitchen, Mr Fontain told him.
Graham ran to the kitchen, and hurried back with the tin in his hand. He looked around, and found several hundreds of the little pink creatures crawling towards the wall of the outhouse. He shook the tin, and sent a cloud of insect−killer over them. The three people watched as the little creatures crawled more and more slowly. Some of them turned over, weakly waving their legs in the air. Then they lay still.
We won’t have any more trouble from them, Graham said. Horrible little creatures! I’ve neverseen anything like them − I wonder what on earth they were?