He Said She Said - Fly

They were walking the dogs. Suddenly he stopped, coughing and gagging.
"What?" she asked, concerned. "What's wrong?"
"I--" Hack! Hack! "I swallowed something. I--" Hack! Hack! "I don't know what--" Hack! "... It was."
He kept coughing, bending over.
"Close your mouth and try to make some spit, then swallow," she said.
After a moment, he stood up, calming.
"I think it was a fly," he said.
"Gross!" she shrieked.
"Not a big one. One of those little midgey ones."
"Are you OK now?" she asked, rubbing his back.
"Yes," he said, starting to walk again, much to the relief of two very impatient dogs.
"Well," she said, taking his hand, "now we just need to find a spider."
"Wha--?" He paused. "Oh, VERY FUNNY!"