Mosquito pupa respiratory tube, coloured scanning electron micrograph (SEM). The respiratory trumpet is covered in fine hairs to help trap air. This is the breathing tube of a pupa from a Culex mosquito. The pupa, which is less dense than water, floats at the water's surface. The developing mosquito inside the pupa takes oxygen through two breathing tubes (one seen here). The metamorphosis of the mosquito into an adult is completed within the pupal case. Magnification: x200 when printed at 10 centimetres across.