Buzz
The expression dropping like flies usually doesn't signal positive news. At best, it suggests many people are falling behind in something: Tour de France cyclists trailing the pack, celebrities canceling their appearances at Fyre Festival, and so on. At its worst, it means living things within a specific group—like bees—are dying off at an alarming rate.
The origin of the idiom isn't neatly tied to any single event, though it has been in use since at least the mid-1800s. One of its earliest written uses comes from an 1857 article in London's The Standard, where the writer laments the British government's practice of sending soldiers overseas without proper clothing for the climate: 'as if the British uniform always carried the British climate along with it.' The troops were headed to India during what is now known as the Indian Mutiny or the First War of Independence (among other names).
'As we see them in our streets, buckled, and belted, and shakoed, on the coldest winter day, they will land at Calcutta and march to Delhi or elsewhere, under a burning sun, dropping like flies upon the road,' the article describes.
In fact, several early uses of the phrase involved extreme weather conditions. In July 1901, Iowa’s Muscatine Journal reported on a deadly heatwave that gripped Greater New York, stating, 'Men, women, and children are dropping like flies throughout the area.' 'Prostrations are running up into the hundreds,' the paper added.
Why Flies?
There are a few possible explanations for why flies might have been seen as the perfect symbol for illustrating illness or death, particularly in the context of Merriam-Webster’s description: 'over a short period of time and in large numbers.'
One reason is that flies have short lifespans. A typical housefly lives for about four weeks, and fruit flies have even shorter lives. Additionally, flies are much easier to kill than other creatures—just one quick swipe with a fly-swatter does the job.
Cluster flies, which resemble houseflies, could explain how the 'large numbers' aspect of the idiom came about. These insects tend to gather in large groups in warm areas, and many of them make their way into homes to hibernate as the weather cools. They can gather inside walls without being noticed. Unfortunately, many of them never make it back outside, instead dying from exhaustion as they attempt—and fail—to escape through windows and other openings. Essentially, they end up dropping… like flies.
