That firewood you lugged into your house last night may dispense more than just warmth this winter; it could fill your house with flying insects.

Borers, to be specific. Two of the most common being the banded ash and the blackhorn pine borer, said Jay Karren, Utah State University Extension entomologist.If they are in your house, don't panic. They are about as harmless as that bore sitting next to you watching television.

"They can't sting, bite or poison or infest anything in your house," he said. "But they can be a nuisance."

He said the insects are black beetles marked with a yellow stripe, often confused for wasps.

What they are looking for when flying around your house is another log - a moist one at that. He said furniture and other wood found in your house is too dry to interest them.

The process begins in the outdoors when the female borer lays her eggs, most frequently on the bark of pine and aspen wood. This usually takes place in the summer months. The grubs then hatch and bore down into the wood and begin feeding. When cold weather comes, they go into hibernation.

What can bring the insects out of that hibernation is the spring-like warmth of a house. When brought inside for any length of time, the insects will pick up where they left off and resume feeding.

Being near pupation stage, they eventually come out of the log and begin flying around the house. The females begin looking for other logs to lay their own eggs on.

"You fool them when you bring them into the house," Karren said. "This can cause you a problem."

To avoid this problem, keep firewood outside of your house until you're ready to burn it, he said.

If the borers are already in your house, they can be easily killed with most household aerosol insect sprays. Look for them around windows where light attracts them.

"You do want to make sure to vacuum them up after you kill them," he said. "Look for them falling down into cracks, crevices and in carpets."

If the borers are not disposed of, he said they can attract dermestid beetles or carpet beetles.

While the dermestid beetle is also harmless, it is fond of laying its eggs in flour and other stored food products around the house. The fuzzy body larvae of this beetle is commonly confused with the larvae of the true weevil.