ILLUSTRATIONS. 



Plate 1. 

 Plate 2. 

 Plate 3. 

 Plate 4. 

 Plate 5. 



Fig. 



1 



Fig. 



2 



Fig. 



3 



F'ig. 



4 



Fig. 



5 



Fig. 



6 



Fig. 



7 



Fig. 



8 



Fig. 



9 



Fig. 



10 



Fig. 



11 



Fig. 



12 



Fis 



13. 



Fig 



14 



Fig. 



15 



Fig 



16 



Fig 



17 



Fig 



18 



F'ig. 



19 



Fig 



20 



Fig 



21 



Fig. 



22 



Fig 



23 



24. 



Fig 



25. 



Fig 



26. 



Fig 



27. 



Fig 



28. 



Fig 



29. 



Fig 



30. 



PLATES. 



Page 



California Ground Squirrels 5 



Douglas Ground Squirrel and Oregon Ground Squirrel 52 



Belding Ground Squirrel and Sierra Golden-mantled Ground Squirrel- _ W 



Yuma Round-tailed Ground Squirrel and Mohave Ground Squirrel 76 



Desert Antelope Ground Squirrel and Fisher Ground Squirrel 98 



figures in text. 



Page 



Ears of several species of ground squirrels 9 



A typical example of the California Ground Squirrel 13 



Four characteristic poses of a California Ground Squirrel 15 



Mound and burrow entrance of a California Ground Squirrel : 16 



"Hog-wallow" land, showing burrow of the California Ground Squirrel_ 18 



Plot of excavated burrow of a male "digger" squirrel 19 



Plot of excavated nesting burrow of a female "digger" squirrel 20 



Plot of excavated coloniel burrow-system of "digger" squirrel 21 



Nest of male "digger" squirrel 23 



Nest of female "digger" squirrel 24 



Nest and small young of "digger" squirrel 25 



Diagram showing extent and height of breeding season in California 



Ground Squirrel 26 



Drawings to show relative extent of cheek-pouches in California and 



Belding Ground Squirrels 33 



Heads of wheat gathered by one "digger" squirrel 35 



Metropolis of "digger" sciuirrels in a grain field ^_ 36 



Badly infested hillside 41 



Map showing distribution of the "digger" squirrels 46 



Map showing distribution of the Oregon, Belding, Stephens Soft-haired 



and the Round-tailed Ground Squirrels — 61 



Plot of excavated nesting burrow of Oregon Ground Squirrel 64 



Life photographs of Oregon, Belding and Sierra Golden-mantled Ground 



Squirrels 69 



Plot of excavated burrow of female Belding Ground Squirrel 71 



Third-grown young Belding Ground Squirrel — 72 



Diagram showing the ranges of California Ground Squirrels according 



to life-zones 78 



Map sliowing distribution of the Golden-mantled and Antelope Ground 



Squirrels 86 



Hibernating San Bernardino Golden-mantled Ground Squirrel 93 



Feet of Desert Antelope, Stephens Soft-haired and California Ground 



Squirrels, to show tubercles and extent of hairing 95 



Young Desert Antelope Ground Squirrel — 101 



Young Nelson Antelope Ground Squirrel 106 



Adult pair of Nelson Antelope Ground Squirrels 107 



Diagram showing relative economic importance of different ground 



squirrels 114 



Note. — Figures indicating page numbers refer to folios at foot of pages. 



