212 NATURE-STUDY 



head down, with the breathing tube thrust up through the 

 surface-film and adhering to it. If they are suddenly dis- 

 turbed, they quickly fall to the bottom. 



The larva changes to a bent form, the pupa, which 

 breathes air by means of thoracic spiracles. It now has wing 

 pads. This pupa finally splits open on the back, and the 

 winged mosquito appears, using the old pupal case as a raft 

 until its wings are strong enough to fly. All these changes 



Fig. 71. Mosquito. 



take place in a few days, if the conditions are favorable, and 

 they are interesting to observe in the school-room. Keep a 

 number of larvae in a dish of water with a screen over it. 

 Watch frequently, and probably you will see the mosquito 

 emerge. 



The male mosquito differs in appearance from the female. 

 He has long feathery antennae, believed to be organs of hear- 

 ing, and he has no sting or, rather, beak. Therefore he does 

 not " bite " as does the female. She has smaller antennae, and 

 her mouth-parts are a collection of slender, sharp, piercing, 



