98 THE BIOLOGY OF HARDING COUNTY 



(b) Gophers. The carbon bisulphide method of killing 

 prairie dogs can 'be applied to gophers. Trapping and digging - 

 out as well as shooting is very much more simple with gophers 

 than with prairie dogs, and is usually sufficient. 



(c) Rabbits are chiefly destructive to young fruit trees and 

 gardens. We heartily recommend that anyone setting out an 

 orchard or garden to first have it fenced with a rabbit-proof fence. 



(d) Wild Mice are caught in baited traps even more easily 

 than the house mouse. Of course, the best way to keep down 

 the mice in the fields and meadows is to allow hawks, owls and 

 snakes to be unmolested. 



(e) Blackbirds, crows, magpies, and jays are all highly use- 

 ful during the most of the year. Occasionally they are trouble- 

 some for short periods. At such times it is recommended that they 

 be frightened away rather than killed. 



(f) Grasshoppers are abundant but ordinarily not destruc- 

 tive. It is occasionally worth while to soak binding twine in tar. 



(g) Striped potato beetles can usually be controlled by proper 

 application of Paris Green. Since the few individuals which 

 winter are the ones which multiply sufficiently to cause the 

 trouble, it is good economy to go over the patch shortly after the 

 potatoes are up and to kill these adults before they have laid eggs. 

 If clumps of yellow eggs are observed on the lower side of the 

 leaves they ought to be destroyed. During a hot day this can be 

 most delicately done by picking off that portion of the leaf and 

 allowing it to dry up. The bur-tomato, or buffalo-bur thistle 

 (Solanum rostra-turn) is frequent in this -area, especially on deserted 

 ground. This plant is fed upon by the potato beetle, which by 

 its means can exist long distances from potato fields. Since these 

 plants are easily killed, the wide awake farmer, and the one who 

 endeavors to save himself future work will cut down all avail- 

 able plants of this species. This plant, by the way, is the original 

 food plant of the potato beetle (Leptinotarsa decinlincata) . Un- 

 til the cultivated potatoes were introduced into its range, this 

 beetle was found only occasionally, as we found it, on the scat- 

 tered Solatium rostratum,. 



3. PARTICULALY USEFUL ANIMALS. 



(a) Insectivors \ All birds feed their nestlings upon insects, 

 worms or other soft animal food. Most birds subsist almost to- 



