35 



(D) Description of the Nesting-boxes. 



These nesting- boxes are exact copies of woodpecker holes, as we 

 have already stated. Compare the accompanying illustrations of 

 longitudinal sections of natural and artificial holes. A closer description 

 of the boxes, the different measurements, the position of the opening, the 

 boring and arrangement of the interior, can be given more clearly c by the 



A. B. 



LONGITUDINAL SECTIONS OF 



A. Great Spotted Woodpecker's hole. 

 B. Berlepsch's Nesting-box, si 

 (One-eighth natural size.} 



following diagram accompanied by a scale than would be possible by a 

 verbal description. The figures of the first division denote the space 

 between the lid and the opening ; those of the second the diameter of t he 

 opening; those of the third the depth of the boxes Horn the lowe?- 



c -1 



