The proper name for a "candle fly" is Fulgora laternaria. It is a fulgorid planthopper and also referred to as a "lantern fly." Once believed to be luminescent, this insect earned the name "candle" or "lantern" fly, but they don't actually emit light. It is sometimes difficult to control the fulgorid population, so if they find a way in your house, take measures to remove them. If not removed, they may injure indoor plants and continually reproduce.
Set your indoor plants in a bathtub and treat them with an insecticidal soap. It may control the candle flies if applied when the insects are young. They are usually on the underside of leaves, so do not neglect to treat these areas. The bugs have probably found their way to your indoor plants, or they may have already been on the plants when you carried them into the house.
Set sticky bug traps on the soil of your potted, indoor plants. Check the traps daily. Remove the traps when you water the plants and put them back once you have finished, being careful not to get dirt stuck on them.
Vacuum the house well. If any of the bugs are on the floor, you may be able to vacuum them up. Use a hose attachment to vacuum around windows.
Seal windows and doors. If you have a loose window screen or an old screen with holes in it, this may be a place of entry for the bugs. Replace the worn screens. Seal cracks around windows with caulk or underneath doors with weatherstripping.
Treat plants around the outside perimeter of the home with a strong stream of water from a garden hose, dispersing the bugs. Spray the plants daily. Avoid using insecticides on the plants, because doing so may kill insects that are the leafhoppers' natural enemies, such as spiders, lacewings, damsel bugs and lady beetles.
Lay fly traps around the house. Check them daily and replace them as needed.