92 NATURE-STUDY REVIEW [7:4— Apr., 1911 



dish in the sunlight and observe the shadow. What is the appear- 

 ance of the shadow of the tip of the foot? Carefully drop a dry 

 needle on the surface of the water till you can make it float. How 

 does the surface next to the needle look? Is it like the appearance 

 of the water next to the strider's foot? See if you can make a 

 wet needle float. 



2. How do they move? 



How does the strider move? Do all its legs touch the water? 

 Does the beetle move in the same way? Does either insect leave 

 the surface of the water ? Does either go below the surface ? How 

 does the beetle move when under the water? Can you see how- 

 it secures any air to breathe ? Do you see how these insects might 

 secure their food? 



What are the chief differences between the insects as re- 

 gards appearance and habits? Which do you think the more in- 

 teresting insect? Why? 



Are there any other things you would like to observe or 

 learn about these insects? 



Watch the streams and ponds in the neighborhood and no- 

 tice on which ones you find these insects. 



Drawings 



Make drawings of the strider when at rest looked at from 

 above. Beside it make a drawing of a floating needle. 



Make drawing of beetle at rest as seen from above. Make 

 drawing as seen below the water, showing the bubble of air on 

 tip of abdomen. 



References (for teacher) 



Miller's "The Brook Book" ; Comstock's "Insect Life". 



Intermediate Grades 

 (Fall or Spring) 

 Problem 



How are certain insects fitted for living in the water ? 



Materials 



Glass receptacles, some of the following insects : Water boat- 

 man, back-swimmer, giant water bug, water beetles, caddice 

 worms. For the caddice worms the water must be changed oc- 

 casionally or else water plants must be provided. The other in- 

 sects need no special provision. The case-building caddice worm 

 may be found under stones in stream and ponds. It should be 

 studied in the spring so that its transformation may be followed. 



