Observe first of all the feeding habits of the fly. What foods in the home is it most fond of? Make a list of all the food materials it is found to feed on. Where and on what is it found feeding out doors? Do you find it feeding on filth and if so, on what? Do you find it about the barn? Where is it usually found in the barn? How can the fly carry filth to food materials?
In studying the breeding of the fly determine where it lays its eggs and where the maggots a
Collect a few flies and put them in a bottle and drop in with them just a few crumbs of sugar and watch them feed. They cannot chew but a little saliva from the mouth dissolves a little of the sugar which is then lapped up as syrup. Notice what a peculiar sucker they have for drawing up liquids. How can they crawl along in the bottle with their backs toward the floor? Examine the tip of their feet for a small glue pad which sticks to the glass. These glue pads and the sucker are well fitted for carrying filth. Examine the fly carefully and write a brief description of it. What color is it? How many legs? How many wings? Are these transparent? Behind the wings there is a pair of small stubs which is all that is left of the hind pair of wings. Are the eyes large? Can you find a pair of small feelers? Why can you not pick up a fly like you would a grasshopper? Is their eye sight good? Why are they always most abundant on a kitchen screen door? Can they smell?
What are the fly's worst enemies? Will the toad eat them? Do chickens eat them? Have you ever seen chickens scratching in manure and feeding on the fly maggots? Put a few drops of formaldehyde, which you can get from a druggist, in a few spoonfuls of sweet milk or sugar syrup and let the flies eat it and see what happens to them. This is one of our best poison baits for flies which get in the home or collect about the dairy. Formaldehyde is a poison and when used in bait it must be kept out of reach of children. Just about frost, in the fall, watch for the appearance of inactive flies on walls, windows and other parts of the house. These have been attacked by a parasitic disease. These are often found sticking to walls and other objects about the room in the winter, and are commonly thought to be passing the winter.
"The insect we now call the 'house fly' should in the future be termed the 'typhoid fly,' in order to call direct attention to the danger of allowing it to continue to breed unchecked."
—L. O. Howard.