Practical Considerations, 



149 



this is added the well known fact that thus exposed they 

 are more liable to destruction by their numerous enemies, 

 we see at once the importance of this mode of coping with 

 the evil. 



Experiments to test the Effects of Burying at 



different depths, and of pressing the soil. the 



following series of experiments was made with eggs 

 obtained at Manhattan, Kansas, early in November, and 

 similar in condition to those in the first series. Large tin 

 cylindrical boxes, made of different depths, and varying 

 from four to eight inches in diameter, were used; and in 

 order to hasten the result they were kept in-doors at the 

 temperature already mentioned. The soil in all the boxes 

 was finely comminuted and kept in uniform and moderately 

 moist condition. It was gently pressed with the fingers, 

 so as to approach in compactness the surface soil of a well 

 cultivated garden. In each instance the eggs were placed 

 in the center of the box. A large number of eggs were 

 buried at different depths out-doors where they were 

 under natural conditions of soil pressure and temperature. 

 The soil was a tolerably stiff yellow clay, and was pretty 

 well compacted by many heavy rains, after the frost was 

 thawed out. The results of the out-door experiments 

 comport with those made in the boxes. The eggs being 

 placed at every depth from one to eighteen inches, and 

 each batch covered with a wire screen, the result was accu- 

 rately determined. All at one inch below the surface 

 hatched ; about one-third of those at two inches managed 

 to escape, and none from any greater depth. Examined 

 May 12th, they had hatched down to a depth of twelve 

 inches, and worked their way upward, and horizontally, 

 seldom extending more than one inch in the former, or 

 more than two inches in the latter direction. Most of 



