14 



SPERMOPHILES OF THE MISSISSIPPI VALLEY. 



the legs, wings, heads, and jaws of grasshoppers, beetles, and various 

 other insects, the skins of caterpillars, and a great variety of things, 

 as shown in the tables prepared from the examinations. 



Unlike the contents of many birds 7 gizzards, everything had been 

 chewed, not swallowed whole: very few complete insects were found in 

 condition to be identified although it was often possible to recognize 

 the genus but rarely the species. Grains and seeds could be iden- 

 tified more frequently. Softer materials, as foliage and flowers, could 

 be easily distinguished as such, but the species could seldom be 

 told. As far as possible the different materials from each stomach 

 were separated and the relative proportions carefully estimated. The 

 difficulty in perfectly separating the different kinds of food prevented 

 any attempt at weighing or measuring to obtain precise proportions. 

 Hence the percentages given are only approximate. 



In examining the contents of cheek pouches much more definite 

 results were obtained. The seeds and grains carried in them were 

 usually in perfect condition and easily identified by comparison with 

 seeds in the laboratory collection. 



In the preparation of this bulletin the mass of original notes con- 

 tributed by observers has been supplemented by frequent references to 

 the literature of the subject, and numerous extracts have been made 

 from reliable sources. The results of the investigations of several ex- 

 periment stations have been freely used. Part of the chapter on methods 

 of destruction, and some of the notes on Spermophilus tridecemlineatus, 

 S. franJclinij and S. richardsoni, together with the plates illustrating 

 these species, have already appeared in a paper by the author in the 

 Annual Report of the U. S. Department of Agriculture for 1892, pp. 

 186-189. 



It would be impracticable, even were it desirable, to mention the 

 large number of correspondents who have contributed data. Some 

 have sent in specimens, others valuable notes on the range or habits 

 of the several species, while the answers received to letters of inquiry 

 on the subjects of distribution and bounties alone number several hun- 

 dred. Much information on the distribution of these spermophiles is 

 still needed from localities near the limits of their ranges. But without 

 the assistance so freely given it would have been almost impossible to 

 determine precisely the areas inhabited by the species, and acknowledg- 

 ments are due to all who have aided the work. 



