Page:Insects - Their Ways and Means of Living.djvu/392

 The mosquito pupa (Fig. 174 F) also lives in the water, but is quite a different looking creature from the larva. The thorax, the head, the head appendages, the legs, and the wings are all compressed into a large oval mass from



which the slender abdomen hangs downward. The pupa, owing to air sacs in the thorax, is lighter than water and, when quiet, it rises to the surface where it floats with the back of the thorax against the surface film. The pupa has lost the respiratory tube and the posterior spiracles of the larva, but has acquired two large, trumpetlike breathing tubes of its own that arise from the anterior part of the