654 THE POPULAR SCIENCE MONTHLY. 



several radii in their claws, and draw them up and let them go sud- 

 denly ; such a habit may have been the foundation of the remarkable 

 device adopted by Hyptiotes. 



One further inquiry is suggested by the fact that the net consists 

 invariably of four radii. Whatever other variations there may be in 

 the spider's work, as to the size and proportions of the net, and the 

 number of interradial lines, the number of radii is constant. In more 

 than a hundred nets, I have found the number to be four, never more 

 nor less. Now, this seems to offer a confirmation of the common idea 

 that spiders' webs, like bees' cells, are constructed with absolute ac- 

 curacy, and are models for poor humanity. 



Fig. 11. Net of Nephila plumipes, made in a wire frame, and photographed upon wood 

 reduced. In nature, the free radii, as ahove described, occupy about % of the area ; but the 

 web oi which a figure is given was made upon a frame, the limits of which seem to have 

 interfered with the extension of the loops above the level of the centre of radiation. 



But Prof. Jeffries Wyman has shown that no such exactitude pre- 

 vails with the cell of the honey-bee ; for, while the average diameter of 

 a large number of worker cells is about one-fifth of an inch, yet the 

 difference between two cells has been found to be one-fortieth of an 

 inch, and the aggregate diameter of ten cells may differ from that of 

 another set of ten cells one-fifth of an inch, or the diameter of a 

 single cell. The width of the sides varies to an appreciable extent ; 

 likewise the angles between the sides ; a fourth face is often intro- 

 duced into the base, and the rows of cells may be greatly out of line ; 

 in short, while it is probable that the bees work with reference to an 

 ideal or type implanted in them, Prof. Wyman is inclined to doubt 

 whether a type-cell is ever really made. 1 



The reader will now be prepared to hear that, after careful exami- 

 nation of large numbers of nets of many different spiders, I have yet 

 to find one in which the irregularities could not be detected by the 



1 " On the Cells of the Honey-bee" ("Proceedings of the American Academy of Arts 

 and Sciences," January 9, 1866, pp. 68-82 ; 6 figures). 



