35 



(d) Description of the Nesting-boxes. 



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

 liave 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 by the 



A. 



B. 



LONGITUDINAL SECTION'S OF 



A. — Great Spotted Woodpecker's hole. 

 B. — Berlepsch's Nesting-Box, size B. 

 {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 hd and the opening ; those of the second the diameter of the 

 opening; those of the third the depth of the boxes from the lower 



c 2 



