ROADSIDE LIFE. 



225 



touch one of the turns of the spiral line, and observe 

 the result when you attempt to take the stick away. 

 In a similar manner touch one of the radiating lines, 

 and also some of the 

 lines that form the irreg- 

 ular outer framework of 

 the web. You will dis- 

 cover that there are two 

 kinds of silk in the web 

 of an orb-weaver, which 

 differ in two important 

 characteristics ; note what 

 these are, and determine 

 to what extent each kind 

 is used. What advanta- 

 ges are gained by the use 

 of each of these kinds of 

 silk? 



If you have the use of 

 a microscope, press a 

 glass slip against a web 

 so that a section of it shall 

 adhere to it, and examine 

 this section with a micro- 

 scope. Make a sketch 

 showing the difference in 

 appearance of the two 

 kinds of silk. 



Find a partially com- 

 pleted web and observe 

 that a temporary, spiral 

 stay-line (Fig. 193, a, a) is 

 used in the construction of the web before the appli- 



FlG. 194. — A dewy morning. 



