Otlier Invertebrate- Animal Study 



483 



THE FILMY DOME 



Teacher's Story 



IKE bubbles cut in half, these delicate domes 

 catch the light rays and separate them like a 

 prism into waves of rainbow colors. One of 

 these domes is usually about the size of an 

 ordinary bowl, and is suspended with the open- 

 ing on the lower side. It is held in place by 

 many guy-lines which attach it to surrounding 

 objects. Above a filmy dome are always 

 stretched many crisscrossed threads for some 

 distance up. These are for the purpose of 

 hindering the flight of insects, so that they 

 the web. The little spider, 

 just below the center of the 



will fall into 

 back downward, 



which always hangs, 



dome, rushes to its prey from the lower side, pulls it through the 

 meshes of the web, and feeds upon it. But any remains of the insect or 

 pieces of sticks or leaves w^hich may drop upon the web, it carefully cuts 

 out and drops to the ground, mending the hole very neatly. 



LESSON CXIII 



The Filmy Dome 



Leading thongJii — One little spider spins a filmy dome, beneath the 

 apex of which it hangs, back downward, awaiting its prey. 



Method — On a sunny day in late summer or early autumn, while walk- 

 ing along woodland paths, the careful observer is sure to see suspended 

 among the bushes or in the tops of weeds, or among dead branches of 

 young hemlocks, the filmy dome webs. They are about as large as a small 

 bowl, and usually so delicate that they cannot be seen unless the sun 

 shines upon them ; they are likely to be exquisitely iridescent under the 

 sun's rays. Such a dome may be studied by a class or by the pupils 

 individually. 



Observations — i. Where did you discover the filmy dome? "What is 

 the size of the dome? Does it open above or below? How is it held in 

 place? 



2. Are there many crisscrossed threads extending above the dome? 

 If so, what do you think they are for? 



3. Where does the spider stay? Is the spider large and heavy, or 

 small and delicate? 



4. What does the spider do if an insect becomes entangled in its web? 



5. Throw a bit of stick or leaf upon a filmy dome web, and note what 

 becomes of it. 



"With spiders T had friendship made. 

 And watch' d them in their sullen trade." 



— Prisoner of Chillon. 



