2^8 INSECTS. PHYLUM ARTHROPODA 



the larva becomes a pupa, which is shaped Hke a comma. It 

 can swim, in much the same way as the larva, but instead of 



Fig. 190. — A mosquito. Anopheles, sucking blood. — After Nuttall and Shipley. 



The curved line under the head is the labium. 



having one respiratory siphon on the abdomen it has two just 

 behind the head, which are used in the same way. The pupa does 

 not feed, and after a few days the adult gnat emerges into the 



Fig. 191.— The life-history of the house fly {Musca domesiica).— From Theobald. 



a, Mandible of larva with adjacent structures ; b, larva ; c, anterior spiracle of the same ; d, eggs ; e, pupa 



case ; /, remnants of spiracle on the same. 



air through a dorsal split, standing on the floating pupal skin 

 until its own has hardened. There are several generations in the 

 course of the year. 



