Brian Hopkins, age 13, of Akron, Ohio, for his question:

ARE BLOWFLIES ALL BAD?

Basically, blowflies can be regarded as bad guys, but they also occasionally do some good. They can dispose of the bodies of dead animals that otherwise would decay and perhaps cause problems. Also, some adult blowflies pollinate plants.

But basically, they cause more harm than they do good things for man. Their eggs are often laid in meat or in the wounds of living animals. The eggs quickly hatch into wormlike maggots which tunnel through flesh. Maggots are dangerous because they spread disease germs.

Blowflies should be kept out of houses and great care should be used to keep all food out of their reach. Garbage cans should be tightly covered, because blowflies breed in them. These flies may have thousands of descendants in just a few days.

The blowflies have bodies colored a metallic blue or green. Because of their appearance, some of these flies are called bluebottles or greenbottles. Some are the size of houseflies and others are three or four times as large.

The blowfly maggots that eat the flesh of living animals are called screwworma and wool maggots. The eggs are laid in open sores in the hides of living stock. They may cause death to farm animals.