House fly adult is about (4-7.5 mm) long, female larger than male. Mature larva is about (7-10 mm). Adult face has 2 velvety strips, silver above and gold below: thorax has 4 narrow stripes: no pale spot behind head or rear tip of thorax: sides of abdomen usually pale: sponging mouth parts. Larva is eyeless, legless, tapered from rear to head, which is a pair of dark hooks. Adult is dull gray. Larva is cream colored and greasy looking. Females lay eggs on almost any warm, moist material with adequate food supply for egg-laying and larval development.Most house flies stay within 1-2 miles of their larval habitat if food is available, though some have migrated up to 20 miles.
During the day, they rest less than 5 ft. from the ground: at night, mainly above 5 ft, but near their food sources. House flies are general feeders on liquids: attracted to many substances, from excrement to human foods House flies can liquefy solid foods by regurgitation. Adult female lays oval, white eggs singly in clusters of 20-50, laying 350-900 eggs in her lifetime. Eggs hatch in 8-20 hours. Larvae go through 3 instars in 3-7 days at 70-90 degrees F. Full grown larvae go to a cool dry place to pupate, traveling up to 150 fee in 3-4 days. Pupa goes from yellowish to black during a period of a few fays to a month, depending on temperature and humidity. After emerging, the body the wings dry within about an hour. Development from egg to adult can be as few as 6 days, with 10-12 generations per summer adults live 15-25 days.