The Halloween pennant is one of the more common members of its genus. Distinctive wing markings include a complete brown band (not just a spot) positioned just short of the wing tip.
Unlike most dragonflies, male Halloween pennants are not territorial toward each other. Therefore you may see groups of them perched on twigs and grasses on the margins of ponds and other still waters, looking for females.
Although most dragonflies are usually seen near ponds, wetlands, and other slow-moving waters, where they breed, this species is also often seen hunting insects in open areas such as old fields and grasslands.
Similar species: The calicon pennant (C. elisa) has similar colors and wing markings, but the dark mark positioned short of the wing tip is a single spot, positioned close to the leading edge of the wing and not extending as a band to the trailing edge.
Learn more about this and other dragonflies on their group page.