RODENT PESTS OF THE FARM. 



11 



FIG. G. Types of special pocket-gopher traps. 



to a shovel or spade handle and attaching an iron foot rest about 15 

 or 16 inches above the point. By forcing this instrument 

 into the soil near the pocket -gopher workings, or a foot or 

 two back of fresh mounds, one can feel the open tunnel as 

 the point breaks into it. The hole may be enlarged and its 

 sides made firm by pressing the soil laterally with the probe. 

 A bait or two should be dropped into the tunnel and the 

 probe hole covered. Care should be taken to place the baits 

 in the main tunnels rather than in the short laterals leading 

 to mounds. Different forms of probes have been used suc- 

 cessfully by the Biological Survey in its demonstration work. 

 Two of the better kinds are illustrated in figure 7. 7" 



GROUND SQUIRRELS. 



More than 50 species and races of ground squir- 

 rels, or spermophiles, 1 inhabit the United States 

 and Canada, and some of them are so numerous 

 in agricultural regions as to be a constant menace 

 to the crops. The spermophiles comprise a group 

 of long, slender animals, of grayish or grayish- 

 brown color sometimes mottled or striped and 

 with a medium or long tail, usually less bushy 

 than that of the larger of the tree squirrels. 

 These ground squirrels are often, but wrongly, 

 called " gophers " and are locally named " dig- 



i Genus Citellus. 



I? 

 .1.1. 



FIG. 7. Convenient 

 probes for locating 

 pocket-gopher runs. 



