What are the characteristics of Culex and Culiseta larva?

• A. Short siphon, hang vertically
• B. Long siphon, hang diagonally
• C. No siphon, horizontal
• D. Siphon absent during development

Answer: (B)

Larvae breathe through a siphon, and the length of that siphon influences how they position themselves at the water surface. Culex and Culiseta have a relatively long siphon, so they keep the siphon touching the surface to breathe while their bodies hang at an oblique, diagonal angle. This diagonal posture lets them feed and move just below the surface while still drawing air from above.

In contrast, other mosquito groups with shorter or no siphons tend to hold their bodies more parallel to the surface or in different orientations, not the diagonal hang seen with these two genera. So the combination of a long siphon and a diagonal hang is the hallmark for Culex and Culiseta larvae.