Packard.] ESTSECTd OF THE POND Al^D STKEAM. 145 



tion of this tube being maintained bj^ a pencil of radiating 

 hairs, attached to a shorter projection at the end of the 

 bod}'. The air is rapidly absorbed b}' the unusually large 

 trachea, nearly filling the longer tube. After taking a fresh 

 breath it often swings its head around, mouth upwards, its 

 tail being the pivot, mowing the surface of the water, if 

 clouded with decaying matter, with its jaws. The young 

 Anopheles, the fly of which is the four-spotted mosquito 

 found in houses late in autumn and early in spring, is a 

 surface breather. But the head and thorax are scarcely 

 heavier than the hind body, and along its whole length are 

 tufts of hairs which spread out and act as floats to the body. 

 The mouth-parts are tufted more distinctly than in the 



Fig. 109. 



A B 



Mosquito larva and pupa. 



young mosquito. In this larva the l>ody ends in four flesh}^ 

 finger-like appendages, in wliich the tracheae may be dis- 

 tinctl}^ seen. 



In its pupal stage the mosquito is quite a different being. 

 Its life is regulated by a new code. It scorns food of all 

 sorts, and like some religious devotee lives ou air alone, and 

 that in homeopathic doses. The enormous thorax is almost 

 a deformity, and now, instead of breathing through its tail, 

 it bears two club-shaped respiratory tubes on its back (Fig. 

 109, (I). These are situated on the site of the future tho- 

 racic spiracles of the fly. 



10 ^ 17 



