Till' I'lJCKIvR. 41 



in the saw-dust-like chippings. No extraneous material is 

 ever employed. 



Dimensions. The data at hand is so incomplete as to admit 

 of no constant comparison between different parts of the 

 countr3s or living- and dead trees, and hard and soft grained 

 woods ; but the depth of excavation appears to be least in the 

 Southern states ((> to 14 inches), and greatest in New York 

 and New England (10 to -M) inches), Illinois ( 14 to 24 inches), 

 Pennsylvania (10 to IS inches), and Minnesota (1) to 18 

 inches). The averages in general, together with the maxi- 

 mum and minimum measurements for the United States, are 

 given in inches and hundredths. The difference in the meth- 

 ods of measuring are so great that much data other than the 

 entrance diameter could scarcely be relied upon, but undoubt- 

 edly the depth of cavit}' depends in no small degree upon the 

 quality of the wood. 



MIN. MAX. .WER. 



Diameter of Entrance 2.20 5.00 3.28 



Diameter of Cavity near Bottom 4.50 10.00 7.67 



Depth of Cavity from Entrance 6.00 36.00 15.79 



Total Length of Cavity 9.00 40.00 18.50 



