The Libellulidae family, also known as skimmers, is the largest and most diverse family of dragonflies worldwide, with more than 1,000 species. Extremely diverse in both colors and patterns, skimmers can rival butterflies in terms of their bold coloration. Widely varying colors and patterns often allow for relatively easy identification of male skimmers in the field, based on a combination of body, eye and wing color and pattern. Immature males and females, however, often look very different and can lead to confusion when trying to identify skimmer species. 

Slaty skimmers (Libellula incesta) are common throughout Massachusetts and are one of the most widespread dragonfly species on the state. Slaty skimmers can be seen from June through early September, and are often found around well vegetated ponds, lakes and slow streams, but adults also forage far from water, along forest edges, fields and clearings. Like many skimmers, males perch on top of tall grasses and weeds in sun lit areas. 

Males, like the one in these pictures, have a thorax and abdomen that is entirely dark blue, with a black face and eyes. The combination of an all-blue body and the dark eyes and face are distinctive for this species. Additional characteristics include mostly clear wings, with the exception of black stigma at the top outer portions of all four wings and slightly dusky wing tips. Female slaty skimmers, on the other hand, are brown with a pale dorsal stripe and ivory patches on the sides of their thorax. Both sexes are approximately 2 inches long when full grown.