27O ECONOMIC MAMMALOGY 



become abundant, might be destructive. 1 In North Dakota the Maxi- 

 millian pocket mouse (Pcrognathus fasciatus) was found feeding 

 mainly on seeds of knotgrass, pigweed and Russian thistle, but it takes 

 many other seeds of weeds and grasses and destroys grasshoppers; not 

 very harmful, if at all, and in many ways beneficial. In the same 

 state the food of the dusky pocket mouse (P. flavescens perniger) con- 

 sists largely of weed seeds, though it nibbles garden vegetables. Its 

 destruction of weed seeds counterbalances the small amount of damage 

 done to crops, but it is not abundant enough to do much either way. 2 

 From Bailey's Texas report we obtain the following items: 3 His- 

 pid pocket mouse (P. hispidus) : a market gardener complained of 

 their "digging up the seeds as fast as he could plant them . . . but a 

 few night's trapping would have cleared them all out." Kansas pocket 

 mouse (P. h. par adorns) : one in Texas had corn in its pocket, one in 

 January "had its pockets full of Convolvulus seeds," one in South 

 Dakota in June "had its pockets full of Cymopterus seeds" ; two 

 rattlesnakes each contained one of these mice. Black-eared pocket 

 mouse (P. h. spilotus Merriam, 1889, equals P. H. hispidus Baird, 1857, 

 according to Miller) : one had Mimosa seeds in its pockets and one 

 "had its pockets full of Petalostemon seeds." Baird pocket mouse 

 (P. flavus) : favorite food is wild sunflower and pigweed seeds. Mer- 

 riam pocket mouse (P. merriami) : juniper seeds and corn found in the 

 burrows. Dutcher pocket mouse (P. m. gilvus) : in September found 

 feeding on the seeds of shrubby Baccharis. Cope pocket mouse (P. 

 flavescens copei) : the type specimen was taken from a rattlesnake 

 stomach. Three topotypes had millet seeds in their cheek pouches. 



Kangaroo rats in some agricultural districts are abundant and de- 

 structive. "No rodent that occurs in the San Luis Valley, except the 

 prairie-dog, is so abundant and destructive . . . very destructive to 

 grain of all kinds and in some sections is a serious pest." Half a 

 bushel of peas and other seeds have been found in a single burrow. 

 Their burrows honeycomb irrigation ditch banks, and their mounds are 

 as large as a medium-sized washtub, 4 sometimes from 2 to 4 feet high 

 and 6 to 8 feet wide. 6 Horses often break through into their burrows. 

 They sometimes store as much as 12^ pounds of forage in one den, 



1 Bailey, Farmers' Bull, No. 335, p. 21, 1908. Burnett, Office Colorado State En- 

 tom. Circular No. 25, pp. 17-18, 1918. 



2 Bailey, A biological survey of North Dakota, N. Amer. Fauna, No. 49, pp. 119, 

 121, 1926. 



3 Bailey, Biological survey of Texas, N. Amer. Fauna, No. 25, pp. 135-143, 1905. 



4 Burnett, Office Colorado State Entom. Circular No. 25, p. 18, 1918. 

 8 Bailey, Animal life of Carlsbad Cavern, p. 82, 1928. 



