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Home Nature-Study Course. 



THE LARVA 



Observations by Pupils-' 



(i). Note whether all the wrigglers are of the same general shape or 

 whether some of them have a very large head ; these latter are the 

 pupae and the former are the larvae. We will study the larvae first. 

 Where do they rest when undisturbed? Do they rest head up or 

 down? Is there any part of their body that comes to the surface of 

 the water? 



(2). When disturbed what do they do? When they swim do they 



go head or tail first ? When they float do they go upward or downward ? 



(3). Observe one resting at the top. At what angle does it hold 



itself to the surface of the water? Observe its head. Can you see the 



jaw brushes revolving rapidly? 

 WHiat is the purpose of this? De- 

 scribe its eyes. Can you see its 

 antennae ? 



(4). Note the two peculiar tubes 

 at the end of the body and 3ee if 

 you can make out their use. 



(5). Note especially the tube 

 that is thrust up to the surface of 

 the water when the creatures are 

 resting. Can you see how the 

 opening of this tube helps to keep 

 the wriggler afloat? What do 

 you think is the purpose of this 

 tube? Does it not become filled 



Mosquito larva or wriggler. 



with water when the wriggler is swimming? Can you see the two air 

 vessels or trachae extending from this tube along the back the whole 

 length of the body? 



(6). Note the peculiarities of the other tube at the rear end of the 

 body. Do you think the little finger-like projections are an aid in swim- 

 ming? How many are there? 



(7). Can you see the long hairs along the side of the body? 



(8). Does the mosquito rest at the bottom of the bottle or aquarium? 



PUPA 



(9). What is the most noticeable difiference in appearance between 

 the larva and pupa? 



(10). When the pupa rests at the surface of the water is it the same 

 end up as the wriggler? 



