I'm not 100% sure it is flea :Its color is very dark brown, it could jump about 6 inches heigth and 10 inches length, it bite( draw blood?) ,attract to human, body is very hard, 2 mm long and 1 mm to1.5 mm wide. There is not pet.
I tracked them down to the fire place. The chimey is brick about 13 ft tall.The chimey's cap screen fell out. So bird , squirel or cat could come down
I put the screen back, cleaned out the fire place and put on a wood fire on for about 2 hr. but they are still in the chimey. Then I clean up the chimey with a vacumm,
1 How did the "flea" get inside the chimey?
2 Do flea need food to survice and how long could they live without food ?
3 At what temperature its egg would die ?

THANKS

Fleas do need food to survive. They usually eat blood from a host animal. I don't know how they got into the chimney, but it doesn't seem that it whould have been difficult.

Flea - Wikipedia, the free encyclopedia

The Wikipedia article has some information on temperatures.

If it were my fireplace, I'd light a large fire in it and get it as hot as I could.

It does sound like a flea. There are several species, some of which are that size.

1. Fleas could come in on mice, squirrels, cats, raccoons, any other mammal that could have gotten in.

2. Fleas pupate inside a "cocoon," just like a moth or a butterfly. Inside those cocoons, they can survive until conditions are good for the adult to emerge. Some have lived two years in laboratory conditions.

3. Inside the cocoons, you will have to cook the pupae or freeze them. Four hundred Fahrenheit or 50 below should do it.

A simpler method of getting rid of them would be to dump about three pounds of diatomaceous earth in the fireplace, leaving it overnight, then sweeping and vacuuming it out.

Also check the attic and attic entry points for signs of animals. Remove them and seal the entry points. If you stop the source you stop the pest.