^66 Home Nature-Study Course. 



grass. The web is formed by many lines of silk laid across each other with nO 

 special regularity, making a firm sheet. This sheet is held in place by many guy 

 lines which fasten it to surrounding objects. If the web is touched lightly the spider 

 will rush forth from the tube thinking to seize its prey; but if it be jarred roughly 

 the spider will disappear from its funnel through the back door and will be found 

 with difficulty. The smaller insects of the field, such as flies and bugs, are the 

 chief food of this spider; it rarely attempts to seize a grown grasshopper. The 

 funnel-shaped webs in dark corners of cellars, sheds, etc., are made by a species 

 which is closely allied to the grass spider and has the same general habits, but 

 which builds in these locations instead of the grass. 



Lesson XIX. 



AN ORB WEB. 



Purpose. — To open the eyes of the pupils to the perfection of one of 

 the most wonderful structures made by any of the lower animals. 



Material. — An orb web where the pupils can observe it, preferably 

 with the spider in attendance. 



Observations for the Pupils. — (i). Is the orb web usually hung hori- 

 zontal or vertical? 



(2). Observe the radii or the " spokes" of the web. How many are 

 there? How are they fastened to surrounding objects? Is each spoke 

 fastened to some object or to a frame work of silken lines? 



(3). Observe the silken thread laid around the spokes. Is it a spiral 

 line or is each circle complete? 



(4). Are they the same distance apart on the outer part of the web 

 as at the center? 



(5). How many of the circling lines are there? 



(6). Is the center of the web merely an irregular net or are there 

 bands of silk put on it in zigzag shape? 



(7). Touch any of the "spokes" or the guy lines that hold them in 

 place lightly with the point of a pencil. Do they adhere to the pencil 

 and stretch out as you pull the pencil away? 



(8). Touch one of the circling lines with a pencil point and see if it 

 adheres to the point and is elastic. 



(9). What is the reason for this difference in the stickiness and 

 elasticity of the different kinds of silk in the orb web? 



(10). If an insect touches the web, how does it become more entangled 

 by seeking to get away? 



(11). Where does the spider stay, at the center of the web or in a 

 little retreat at one side? 



