Adult Culex mosquitoes are characterized by a relatively blunt-shaped posterior abdomen, making them appear small and delicate compared to other mosquito genera. Female mosquitoes in the subgenus Melanoconion have distinctive features, including a thorax with a scutum lacking acrostichal setae and broad, flat scales situated posterior to the compound eyes, particularly along the ocular line. Identifying male mosquitoes in the subgenus Melanoconion to the species level can be challenging, often requiring an analysis of the genitalia. For the accurate identification of Culex pilosus females, a notable characteristic is the observation of three teeth on the cibarial armature—a set of specialized spicules, known as cibarial teeth, arranged on a transverse ridge. Both male and female Culex pilosus mosquitoes exhibit dark, short palps, a long dark proboscis, a dark abdomen adorned with somewhat reflective bronze or blue-green scales, a dark thorax with a lighter patch on the dorsal part of the mesepimeron, narrow and dark wing scales, and dark-colored legs.