What color are adult house flies generally?

Adult house flies are generally a dull gray color, which is a distinctive characteristic that helps in identifying them. This dull gray coloration often has a slightly dusty or muted appearance, which aids in their camouflage in various environments, especially where they tend to be found, such as in homes, near waste, or decaying matter. The coloration contributes to their adaptation and survival by making them less conspicuous to predators.

The other color options, such as bright red, shiny green, and black, do not accurately describe adult house flies. Their bright red coloration is more characteristic of certain types of insects like fruit flies, while shiny green is typically associated with other species such as bottle flies. Black may describe some other fly species but is not typical for house flies, as they possess that recognizable dull gray appearance instead.