Four differences, in the order they are easiest to see
Both insects swarm in clouds, both have four wings, and both turn up around windows in spring. Up close they are not similar at all, and the waist settles it faster than anything else.
| Termite swarmer | Flying ant | |
|---|---|---|
| Waist | None — one continuous width from head to tail | Sharply pinched, like two beads on a thread |
| Antennae | Straight, a string of tiny beads | Clearly bent at an elbow |
| Wings | Four, all the same length, well longer than the body | Front pair noticeably longer than the rear pair |
| Color | Dark brown to nearly black, uniform | Black, brown or reddish depending on species |
If the insect is intact, the waist alone is enough. If all you have is a wing, the length comparison is the one that still works.
What the discarded wings tell you
Termite swarmers shed their wings almost as soon as they land, which is why the wings are usually easier to find than the insects.
Four wings of identical size and shape, translucent and slightly milky, in a small pile on a windowsill or in a web — that is a termite. An ant's shed wings come in two obviously different sizes.
Where you find them matters as much as what they are. Wings on an interior sill, in a bath, or around an indoor light fitting suggest the swarm emerged inside the structure. That is a much stronger signal than wings on an outside step, which may simply have blown in.
When each one swarms
Timing narrows it down without settling it. Subterranean termites — the destructive ones in most of North America — swarm in spring, in daylight, often a day or two after rain when the air is warm and still. Drywood termites swarm later in the year, through late summer and autumn, and more often at dusk.
Flying ants swarm across a much broader window, and in many regions the big ant flights happen in mid to late summer. Overlap is common enough that timing should support an identification rather than make one.
What a swarm actually means
A swarm is a colony reproducing, not a colony arriving. Termites only produce winged reproductives once the colony is mature enough to spare them, which in subterranean species commonly takes several years.
So a swarm indoors is not the beginning of a problem. It is the visible moment of one that has been running quietly for some time — and it means the colony is close, because swarmers are weak fliers that do not travel far.
The swarmers themselves will die within a day or two if they cannot find soil and a mate. Killing them accomplishes nothing; the colony that produced them is unaffected.
What to do after a swarm
Collect a few of them, or a pinch of the wings, into a jar or a folded piece of paper. It costs nothing and it gives whoever inspects a definite answer instead of a description.
Then note where they came from. Swarmers head for light, so the window they gathered at is rarely where they emerged. Look instead for the exit — a small hole, a gap at a baseboard, a crack in a slab — and check the timber nearby for the other signs on the main termites page.
Photograph the wings before sweeping them up. It is the one piece of evidence that disappears fastest.