6 Entomology and Zoology Department. [Bull. 168 



direction, however, nothing but concrete or stone will stop 

 him. The strength of the little animals is marvelous. They 

 will heave up the surface of a path trodden so hard that re- 

 peated blows of a pick would be required to break the crust. 

 In like manner the bricks of a sidewalk are pushed up out of 

 place, and on one occasion a run was noticed heaved up across 

 the hard, baked roadway over which a heavy traction engine 

 frequently passed. 



THE FALL SEASON. In the late fall one will observe an in- 

 creasing number of the little mounds of earth often associated 

 with a system of mole runways. The presence of these indi- 

 cates active operations in some of the deeper parts of the sys- 

 tem. Ordinarily a mole makes his way through the soil much 

 as a root does, or a stake when driven by the blows of a sledge. 

 The earth is not excavated, but simply crowded aside. This is 

 true of the work even at considerable epths when the soil is 

 moist. But when the ground becomes harder, as it usually does 

 in the autumn, the mole is obliged to excavate the passageways 

 with his stout front feet and dispose of the loose earth by push- 

 ing it out through openings in the roof of his surface tunnels. 



IN WINTER. At any time in winter when the ground is not 

 frozen too hard, the mole keeps up his work. During the 

 freezing days of January observations have shown fresh bur- 

 rows ridging up a hard crust of snow covering a thin layer of 

 frozen soil. There seems to be no good reason for assuming, 

 as some do, that during hard freezing weather the mole keeps 

 burrowing away beneath the frost line. He could not make his 

 way at this depth by compacting the soil, and observations 

 have not shown loose earth brought to the surface at such 

 times. Again there would be no need to carry on burrowing 

 operations under such unfavorable conditions. The system of 

 passages already constructed could be retraversed in search of 

 food until opportunity offered for extending it. Worms and 

 hibernating insects are just as likely to be found in a passage- 

 way the second or third time it is traversed as they were when 

 it was being constructed, for many of these little creatures of 

 the soil are on the move also. 



FOOD STORAGE. Owing to the peculiar character of a mole's 

 diet, storage of food for an unfavorable period or season 

 would seem out of the question. There seems to be no indi- 

 cations that supplies are thus laid up for a "rainy day." A 



