Four-spotted skimmer (Libellula quadrimaculata) is common, widespread, and misnamed.
Eight-spotted skimmer has two large spots on each wing for a total of eight. Twelve-spotted skimmer has three large dark spots on each wing for a total of twelve. Four-spotted skimmer has two small dark spots on each wing and one large spot on each hindwing for a total of ten. A more appropriate name might be ten-spotted skimmer (Libellula decamaculata).
Four-spotted skimmer is an early season, medium-sized skimmer. It is found from mid-May to September at the edges of boggy lakes and ponds, fens, and slow streams. It is usually seen perched at the top of a tall emergent plant or a weed, often far from water.
It is easily identified up close by the two dark spots on the leading edge of each wing. It is further distinguished by the bright yellowish-brown color on the thorax and front half of the abdomen of juveniles, amber streak with yellow veins at the leading edge of each wing on juveniles, black patch at the base of the hindwing, and narrow yellow stripe on each side of the abdomen. Unlike other skimmers, the female abdomen is tapered like the males, not parallel-sided.