California Darner

As an adult, the California darner is described as a medium-sized dragonfly, typically measuring between 5.7 and 6.4 centimetres (2+1⁄4 and 2+1⁄2 in) in length. California darners are best distinguished by their distinct bright blue diagonal spots on their abdomen. Male California darners have a dark brown to brownish-black body with two blue or green diagonal stripes across each side of the thorax, while the top thorax is plain in color. Most females are polymorphic, although exhibit the same color scheme as males, they may also have greenish yellow markings instead of blue. Females are also heteromorphic with their eyes being light brown in comparison to the males' blue eyes.

The adult flight season occurs during the warmer months, typically occurring from mid-April to late June, which makes it one of the earliest dragonflies to appear during the spring season. In California, they are noted to have a flight season from February to August. California darners are most commonly found throughout the Western United States, with the highest concentration stretching from Baja California to the south of Mexico. They can also be spotted in some parts of Canada, like Vancouver, and in regions of Central America.

The California darner, like many other dragonflies, thrives in aquatic environments with abundant freshwater sources. Accordingly, they gravitate toward freshwater bodies such as lakes, ponds, and marshes at lower elevations. With regard to climate, the California darner is most commonly found in Mediterranean climates, such as California, which is semi-arid, exhibiting wet winters and dry summers.

The California darner typically spends several years maturing from a naiad before transitioning into their adult dragonfly form. When this transformation occurs, it occurs at night, which is believed to be an adaptation in order to avoid being preyed upon by diurnal predators such as birds, frogs, and fish.