55> 



The larva of the c-yoadia of different kinds, during tlieir h)ng })eriod of life un- 

 der ground, must do much toward pulverizing the soil. The larva of some of the 

 tipulidfe, or crane flies, are among the most effective of these minor agencies. I 

 found them last season working in shale and bowlder clay. These materials were 

 honey-combed to a depth of about three inches below the level of the water, and 

 so well was the work done that the mass broke down easily in the fingers. The 

 materials removed in boring their tubes was quickly dissolved or washed away, 

 and penetrating the holes the water rapidly dissolved the partitions or so weak- 

 ened them that even a gentle current carried away the shale and clay in great 

 quantities. 



Many different kinds of ants burrow in the ground often ranging over large 

 areas. The amount of soil worked over each year by these little laborers must be 

 very great. Then there are several kinds of wasps which work more or less ex- 

 tensively in the soil. Some of the bees also work in the ground, or in banks 

 much like cliff swallows. They deposit their eggs at the bottom of a hole or bur- 

 row some two or three inches deep. Often they build out an entrance or porch to 

 the hole, possilily as a protection against intruders. Their work breaks up large 

 areas of material eacii season for the rains of spring and autumn to dissolve and 

 carry away. Many other insects are engaged in this work, but the ones mentioned 

 are perhaps the more important. These little fellows are among the minor 

 agencies of erosion, but the amount of work accomplished each year is immense 

 and can not be neglected in a careful study of erosion and erosive agents. In 

 nearly every case the action of these little animals serves to enrich and fertilize 

 the soil, thus promoting the growth of vegetation while aiding in erosion. 



KETTLE HOLES NEAR LAKE MAXlNKtlCKEE. By J. T. ScOVILLE. 



Kettle holes are phenomena incident to the retreat of glacial ice. They are 

 very numerous in southeastern Massachusetts and are abundaiit throughout the 

 glaciated area wherever the ice halted long enough to form morainic deposits. 

 They vary greatly in size, but are usually somewhat conical in shape. They are 

 often occupied by water forming ponds or small lakes. There are said to be more 

 than 300 such bodies of water in Plymouth Township, Massachusetts. In many 

 cases, however, their walls are of sand or gravel, which do not retain water for 

 any great length of time, so that they are usually dry. The holes are supposed to 

 have been formed somewhat as follows : The clay, sand, gravel and other 

 morainic materials along the margin of the ice were irregularly distributed so 

 that in some places it was so thick as to protect the ice underneath from the 



