1 NORTH AMERICAN FAUNA No. 56 REVISION OF THE NORTH AMERICAN GROUND SQUIRRELS With a Classification of the North American Sciuridae By ARTHUR H. HOWELL Senior Biologist Section of Wildlife Surveys, Division of Wildlife Research Bureau of Biological Survey ^/V^L Issued by UNITED STATES DEPARTMENT OF AGRICULTURE BUREAU OF BIOLOGICAL SURVEY Washington, D. C. ApniL 1938 For mU by xh» Sup«riDtend«ot of Docomenta, Washington, D. C- - -- - - - Wo* ^ ««"»t3 PUBLICATIONS in the NORTH AMERICAN FAUNA SERIES Copies of the North American Fauna not out of print are for sale, at the prices named, by the Superintendent of Documents, Government Printing Office, Washington, D. C. Numbers marked with an asterisk [*] are out of print. *No. 1. Revision of the North American Pocket Mice. By 0. Habt Mebbiam. Pp. 36, pis. 4. 1889. *No. 2. Descriptions of Fourteen New Species and One Nevr Genus of North American Mam- mals. By C. Habt Mbbbum. Pp. 62, pis. 8, figs. 7. 1889. *No. 3. Results of a Biological Survey of the San Francisco Mountain Region and Desert of the Little Colorado, Arizona. By O. Habt Mebbiam and Leonhabd Stejnsgeb. Pp. 136, pis. 14, maps 6 (colored), Sgs. 2. 1800. *No. 4. Descriptions of Twenty-six New Species of North American Mammals. By O. Habt Meb- biam. Pp. 60, pis. 3, figs. 3. 1890. *No. 5. Results of a Biological Reeonnolssance of South-central Idaho. By C. Habt Mebbum and Leonhabd Stbimbgeb. Descriptions of a New Genus and Two New Species of North American Manunals. By C. Habt Mebbum. Pp. 132, pis. 4 (1 colored), figs. 4. 1891. No. 6. Not iaaued. *No. 7. The Death Valley Expedition: A Biological Survey of Parts of California, Nevada, Arizona and Utah. Part II: 1. Birds, by A. K. Fishke. 2. Reptiles and Batrachlans, by Leonhabd Stbi- NEOEB. 3. Fishes, by Chables H. Qilbebt. 1. In- secfB, by O. V. RaET. 6. MoDusks, by K. E. C, Stb ABN8. S. Desert Trees and Shrubs, by. C . Habt Mebbum. 7. Desert Cactuses and Yuccas, by O. Habt Mebbiam. 8. List of Localities, by T. S. Palmeb. Pp. 402, pis. 16, maps 6, figs. 2. 1893. *No. 8. Monograptilc Revision of the Pocltet Gophers, Family Geomyi^ae (exclusive , of the species of Thomomys). By O..Eabi. Meseium. Pp. 258, pis. 20, figs. 71, maps 4 (qoi{ir&d)\ i^[ ,' ; No. 9. Xot iuued. *No. 10. Revision of the Shrews of the Amar&an Genera Blarina and Notiosorex. By C 'Ea&t Mebbum. The Long-tailed .Slwews of .thp East- em United States. By QiJ^iifT; s'. Miii^^l ir.. Synopsis of the American Stiir^wa of i. A Biol^^cal Reconnaissance of the Base of tM .^agkH Peninsula. By Wiltbed H. Osgood. ' Pp.a5i.p!9,7(incl. 2maps). 1904. >*^o. 25. Biological Survey of Texas: life Zones* '. siili Characteristic Species of Mammals, Birdsi Reptiles, and Plants. By Vebnon Bailbt. Pp. 2c'?3,.pls. J6 (Ind. 6 maps), figs. 24 (ind. 16 maps) . ■ im^ ' >/ ".. '"'No.'26.'Rev)fy4dn of the Skunks of the Genus SpUogale. By Abthub H. Howell. Pp. 65, pis. 10 (Incl. 1 map), 1906. No. 27. A Biological Investigation of the Atha- basIm-Mackenzie Region. By Edwabd A. Pbeble. Pp. 574, pis. 25 (incl. 4 maps), figs. 16. 1908. *No. 28. Revision of the Mice of the American Genus Peromyscus. By Wiltbed H. Osgood. Pp. 285, pis. 8 (incl. 1 map), figs, 12 (maps). 1909. *No. 29. The Rabbits of North America. By E. W. Nelson. Pp. 314, pis. 13, figs. 19 (ind. 16 maps). 1909. *No. 80. Biological Investigations in Alaska and Yukon Territory: 1. East-central Alaslia; 2i OgUvIe Range, Yukon; 3. Macmlllan River Yukon. By Wilfbkd H. Osgood. Pp. 96, pis. 6 (1 map), figs. 2 (maps). 1909. (.Continued on page S of cover) NORTH AMERICAN FAUNA No. 56 issued -=^^^^^»L ^y '^* UNITED STATES DEPARTMENT OF AGRICULTURE BUREAU OF BIOLOGICAL SURVEY Washington, D. C. April 1938 REVISION OF THE NORTH AMERICAN GROUND SQUIRRELS, WITH A CLASSIFICATION OF THE NORTH AMERICAN SCIURIDAE By Arthur H. Howell, senior biologist, Section of Wildlife Surveys Division of Wildlife Research CONTENTS Introduction .- 1 Geographic distribution of the ground squirrels.- 2 Habits and economic relations 4 Townsend's ground squirrel and related races 5 Snake Valley ground squirrel 6 Washington ground squirrel 7 Eichardson's ground squirrel 8 Wyoming ground squirrel 10 Uinta ground squirrel 10 Belding's ground squirrel... 11 Oregon ground squirrel. 12 Columbian ground squirrel and related races... 13 Parry's ground squirrel and related races... 16 Yukon Valley ground squirrel. 17 Striped ground squirrels 18 Mexican ground squirrels 20 Spotted ground squirrels 20 Perote ground squirrel 21 Franklin's ground squirrel 21 Rock squirrels 22 California ground squirrel and related races 23 Douglas's ground squirrel 27 Ring-tailed and Goldman's ground squir- rels 28 Lesser tropical ground squirrel 29 Antelope ground squirrels 29 Mohave ground squirrel 30 Round-tailed ground squirrels. 30 Mantled ground squirrels 31 Page Classification of the North American Sciiui- dae 34 Genus Marmota: Marmots 37 Genus CynoTnys; Prairie dogs. — 38 Genus Citellm: Ground squirrels 39 Genus Tamia*; Eastern chipmunks 46 Genus Eulamias: Western chipmunks 47 Genus Sciurus: Tree squirrels - 48 Genus Tamiasciurus: Red squirrels 61 Genus Microsciurus: Pygmy squirrels 51 Genus Syntheosciurus: Pygmy squirrels 52 Genus Glaucomys: Flying squirrels 62 Revision of the genus Citellus S3 History and nomenclature... — 53 Generic and subgeneric names 53 Subgenus Citellus Oken 59 Citellus townsendii group 60 Citellus uashingtoni group 69 Cilettus Tichardsonii group 73 Citellus panyii group 85 Subgenus /c/idoTny* Allen 106 Cilelltis tridecemlineatus group 106 CUellus spilosoma group — 122 Subgenus Poliocitellus, nobis. 133 Subgenus Otospermcphilus Brandt 135 Subgenus NotocUellus, nobis 162 Subgenus Ammospermophilus Merriam 166 Subgenus Xerospermophilus Merriam 183 Subgenus Callospermophilus Merriam 190 Fossil species .-- - 214 Bibliography 217 Index 247 INTRODUCTION The ground squirrels of North America now comprise 97 distinct forms in 31 species. These were arranged in the check list of Miller (1924)^ under the four generic names Citellus, Otospermophilus, Callospermophilus, and AmmosperTnophilus. For many years there has been considerable uncertainty as to the relationships of the genera, subgenera, and species. As a result of the present study, the ' Citations in parentheses refer to the Bibliography, p. 217. 154970—38 1 1 .UPCRINT Ell DENT OF DOGUWtiS. 4 r\f\f\ 2 NORTH AMERICAN FAUNA [No. 56 ground squirrels are now grouped under a single genus, Gitelltos, "which is divided into eight subgenera. The material on which the revision is based is principally con- tained in the collection of the United States National Museum, in- cluding that of the Bureau of Biological Survey. In addition, large series of specimens have been borrowed from several of the larger museums in the United States and Canada.^ Altogether 11,724 speci- mens have been examined and identified. One of the early bulletins of the Bureau — that on the Prairie Ground Squirrels, or Spermophiles, of the Mississippi Valley (Bailey, 1893) — ^treated of the habits of five of the more important species. Other writers have published reports on the habits and economic relationships of various other species, notably that by Grinnell and Dixon (1918) on the Natural History of the Ground Squirrels of California. The group as a whole has not been revised for many years and there has been considerable uncertainty as to the relationships and the proper allocation of many of the species. This publication pre- sents the results of a study of the systematic relationsliips and geo- graphic distribution of the American members of the genus, with a summary of the known facts of their life history, together with a critical study of the systematic classification of all the North Ameri- can members of the Sciuridae, the family of which the ground squirrels are members. The colored plates (1 to 11) here reproduced were made about 40 years ago for the Biological Survey from drawings by Ernest E. Thompson, now known as Ernest Thompson Seton, and were printed in expectation that a report on the ground squirrels would soon be issued ; although the revision for which the plates were made has been long delayed, it is now possible to present the illustrations in this volume. GEOGRAPHIC DISTRIBUTION OF THE GROUND SQUIRRELS Ground squirrels of the genus CiteUus are widely distributed, both in North America and in Eurasia. The type species C. citelhis, ranges from Bohemia eastward through the Union of Soviet-Social- ist Republics into Asia, and the genus, represented in Eurasia by 20 or more described species, occupies parts of southeastern Europe and central Asia eastward into Siberia, Most of the Eurasian forms appear to be quite distinct from those of the New World, but 2 For the loan of material used in this study the author extends thanks to the owners and custodians, as follows : R. M. Anderson, National Museum of Canada ; F. Kermode, Provincial Museum of British Columbia ; Glover M. Allen, Museum of Comparative Zoology ; Albert H. Wright, Cornell University ; H. B. Anthony and G. G. Goodwin, American Museum of Natural History ; Witmer Stone and Wharton Huber, Academy of Natural Sciences of Philadelphia; Earl L. Poole, Reading (Pa.) Public Museum; B. P. Bole, Jr., Cleveland (Ohio) Museum of Natural History; L. R. Dice, University of Michigan Museum of Zjology; William L. Engcls, University of Notre Dame ; W. H. Osgood, Field Museum of Natural His- tory ; W. H. Over, South Dakota Biological Sui"vey ; Myron H. Swenk, University of Nebraska ; C. D. Bunker, Kansas University Museum of Birds and Mammals ; Frederick W. Miller, Colorado Museum of Natural History ; Ernest Morris, State Historical Society of Colorado, Denver ; R. F. Crawford, State College of New Mexico ; William H. Spaulding, Montana State College ; J. S. Stanford, Utah State Agricultural College ; Vasco M. Tanner, Brigham Young University ; Joseph Grinnell and E. R. Hall, Museum of Vertebrate Zoology ; Loye H. Miller, Los Angeles Museum ; L. M. Huey, San Diego Society of Natural History ; Chester Stock, California Institute of Technology ; J. H. Fleming, Toronto, Ontario ; C. B. Garrett, Cranbrook, British Columbia ; P. F. Hickie, Lansing, Mich. ; S. G. Jewett, Portland, Oreg. ; E. T. Seton, Santa Fe, N. Mex. ; William T. Shaw, Fresno, Calif. ; Dayton Stoner, Albany, N. Y. ; and Edward R. Warren, CJolorado Springs, (iolo. laSS] REVISION OF THE GROUND SQUIRRELS 3 those from eastern Siberia — G. huxtoni and C. stejnegeri — are closely related to the Alaskan species C. parryii. The North American ground squirrels occupy a large part of the continent, from the Arctic coast of Alaska and Canada south to (xuerrero and the valley of Mexico. Being inhabitants chiefly of prairies and open mountain slopes, they are absent from the forested regions of the eastern parts of both Canada and the United States. The large ground squirrels of the Barren Grounds {G. parryii and its relatives) range from the shores of Hudson Bay westward to the coast of Bering Sea and are found also in eastern Siberia and on St. Lawrence Island; the striped ground squirrels of the Missis- sippi Valley {G. tridecemlineatus) extend eastward to Michigan and Ohio; the gray ground squirrel of the prairies {G. franklimi) reaches Indiana in its eastward range, and a colony introduced into New Jersey TO years ago still survives there. Practically the en- tire area of western North America, with the exception of the coast region of Washington and a large part of British Columbia, is oc- cupied by one or more species of ground squirrel. In the United States, ground squirrels are so abundant as to be highly destructive to agricultural crops. Their importance as fac- tors limiting the profits of the farmer has long been recognized, and from its early days the Biological Survey has been called upon to direct extensive control campaigns in many parts of the West. North American Fauna No. 56 United States Department of Agriculture "Revision of the North American Ground Squirrels" CORRECTION SLIP-May Be Pasted at Foot of Page 3 Actual date of publication, May 18, 1938 Page 41, line 8 from end: For ^2, read ^. Page 119, line 1: For county spelling, read Moffat. Page 146, line 6 from end: For blank space in parentheses, insert 41fl- 54V-59 5'''^ ^°'^' P^'"^"t^etical measurements insert dMh, to read Page 162, last line of section preceding Notocitellus : For 11, read 1 (San Pablo Page 185, line 12: For 34.3, read 34.9 (skull length). J. 154970—38. HABITS AND ECONOMIC RELATIONS The ground squirrels of North America differ from the tree squir- rels in their habit of living in burrows and most of them become dormant for periods of varying extent, in some cases even more than half the year. During the periods of estivation and hibernation there is a decided drop in temperature, the respiration and blood circulation are reduced to a minimum, the body becomes rigid, and the fat accumulated during the active period is practically all con- sumed. Wlien the animals emerge early in spring they feed spar- ingly at first on green vegetation and bulbs of wild plants or upon newly planted grain, if such is at hand. During the breeding season, wliich follows shortly after emergence from hibernation, the desire for green food increases and the squirrels feed on growing grain, alfalfa, wild herbs, and other succulent plants. Early in summer, as the season of estivation approaches, they turn their attention largely to the seeds of wild plants or to ripening grain ; after feed- ing for a few weeks on such nutritious food they become excessively fat, and are ready to enter on their long sleep. The fondness of certain of the ground squirrels for cultivated grain coupled with their ability to increase rapidly under favorable conditions, has made them one of the most serious pests with which the farmer has to contend. In addition to destroying immense quantities of grain and alfalfa, some species are destructive to cul- tivated fruits and nuts. The burrowing of ground squirrels on steep slopes frequently is the initiating cause of soil erosion, which at times becomes serious. Grinnell and Dixon (1918, p. 608), write of the burrows of the Cali- fornia ground squirrels as follows: ■■' * * their burrows are frequently the cause of much destructive erosion on hillsides during heavy rainstorms. Numerous small landslides have been noted on steep hillsides on the campus at Berkeley, that were plainly caused by the presence of squirrel burrows which had concentrated and conducted the water in narrow channels instead of permitting it to spread out and soak in or run off in the natural way. Ground squirrel burrows are often a serious menace to the safety of irrigation systems. Birdseye (1912, p. 13) tells of a serious washout caused by irrigation water escaj)ing through a Columbian ground squirrel's burrow located in an orchard on the bench above. Lantz (1918, p. 14) cites the destruction of 6 acres of alfalfa caused by the burrowing of a California ground squirrel into an irrigation embankment. An additional count against certain of the ground squirrels is based on the part they play in the dissemination of diseases often fatal to man, as is the case with the Columbian ground squirrel in the spread of spotted fever, the California, Oregon, Uinta, Colum- bian, and Eichardson's ground squirrels in the spread of bubonic plague, and the California ground squirrel and the Utah rock squirrel in the spread of tularemia. 1938] REVISION OF THE GROUND SQUIRRELS 5 The species tliat live on deserts or in mountainous sections are of little economic importance, since they rarely come in contact with agricultural operations. This is true of mantled ground squirrels (subgenus Callospermophilus), antelope ground squirrels (subgenus Ammospermophilus) , round-tailed ground squirrels (subgenus Xerospermophilus) ^ and spotted ground squirrels {Citellus spilo- soma). The most serious damage to man's interests is occasioned by vari- ous species of the typical subgenus {Citellus) and by the rock squir- rels of the subgenus Otospermophilus. Franklin's ground squirrel {C. franklinii) and strij)ed ground squirrels {G. tridecemlineatus and G. mexicanus) are accounted pests in some sections by reason of their destruction of newly planted corn and garden vegetables, but this damage is in part balanced by their destruction of injuri- ous insects. The species that occasion the greatest damage to crops of grain, and against which extensive control operations have been necessary, are the Columbian ground squirrel (G. colu7nhianus) , Richardson's and Wyoming ground squirrels {G. richardsonii richardsonii and G. r. elegans)^ Oregon ground squirrel {G. heldingl oregGnus), Townsend's ground squirrel {G. townsendii), Washington ground squirrel {G. w ashing t oni) ^ and Douglas's and California ground squirrels {G. heecheyi subspp.). Detailed accounts of habits of various species follow. TOWNSEND'S GROUND SQUIRREL AND RELATED RACES =* General hahits. — Townsend's ground squirrel and related races {Gitellus townsendii subspp.) (pi. 1) inliabit dry, sandy, sagebrush valleys and to a lesser extent juniper-covered ridges among lava rocks. They live in dense colonies, digging their burrows under the sagebrush or sometimes out in the open. A burrow dug out by W. P. Taylor, in Humboldt County, Nev., was found to be about 30 feet in length, but only about 8 inches below the surface. Of this, Taylor (1911, p. 218) writes: A nest was found in a large spherical cavity, so arranged that water conld not have gotten into it. Fine straws made np the bulk of it, though white cotton twine had been very largely used to bind the straws loosely together. A couple of rags, a bit of rabbit fur, some wool, and a down feather were also incorporated into the nest. Apparently the burrows intercommunicate. T. H. Scheffer excavated a burrow of the subspecies G. t. town- sendii at Kennewick, Wash., which had been treated previously with carbon bisulphide. The mother squirrel and seven young were found strung along the course of the burrow two of the latter in the nest. Scheffer (in manuscript) describes the burrow as follows: The runway descended rather steeply from the entrance, reaching a depth of 51^ feet at distance of 11 feet along the slope. From this point a branch ran downward to the right, for about 3 feet and ended in the nest chamber. Continuing slightly downgrade to a depth of 6 feet and a distance of 14 feet from the entrance, the main tunnel turned abruptly upward at an angle of about 70 degrees and reached the surface in a partly obstructed entrance 12 feet from the point where excavation was begun. From the place of this up- ward turn the main tunnel had been opened up 5 or 6 feet farther into looser *" Formerly known as Citellus vkAUs subspp. For explanation of change of name see p. 62. 6 NORTH AMERICAN FAUNA [No. 56 earth from an old badger digging. Tliis material was slightly damp as a result of moisture penetrating through soil worked over by the badger long ago. The nest chamber was about 6V2 inches in most dimensions and was located just beneath the consolidated stratum, its roof hollowed out in the latter. It was filled with a perfectly dry nest consisting of fine, grass partly broken and shredded. The two young found suffocated there were concealed in the nesting materials. Like other species of their tribe, these ground squirrels hibernate during a good part of the year — from July to the following Febru- ary. A single individual was seen at Blalock, Oreg., on February 1, 1926; Scheffer found the squirrels out in numbers at Kennewick, Wash., the last week in January ; and R. Scott Zimmerman reports their appearance in Utah the latter part of February. In the Ken- newick territory only a few stragglers were observed after June 20 and all of these apparently were young. In central Utah, however, a few were seen as late as September 12 (1932). The young are born early in March, the litters numbering usually 7 to 10. Jewett (1923, p. 191) records taking a female carrying 13 embryos. Although mainly terrestrial, these little squirrels occasionally climb to the tops of bushes, where they keep a sharp lookout for ene- mies. Their voice is described by Vernon Bailey as "a fine, pro- longed, chippering whistle." Scheffer (in ms.) describes it as follows : The notes or calls of this ground squirrel are very high pitched and com- paratively faint, not nearly so sharp and clear as the chirp of a chipmunk of even smaller size. The more prolonged or sustained of the two common calls might readily be mistaken for the faint trill of an insect, while the clearer, chirping sound can scarcely be distinguished from certain notes of the horned lark. As the little animal enters its burrow on the nearer approach of sus- pected danger, it voices its final protest in chattering tones, faint but not uncertain. Food habits. — ^Like most of the ground squirrels, this species feeds mainly on green vegetation in the early part of the season and later upon the seeds and stems of grasses and other plants. Scheffer, at Kennewick, Wash., observed them feeding' on globemallow {Sphae- ralcea inunroana) ^ silver Indianwheat (Plantago purshii), downy, chess (Bromus tectoi'um), slender wheatgrass {Agropyron pauci- ■flomm), Indian ricegrass {Oryzopsis hymenoides) .^ and tumblemus- tard {Norta altissima), these being the same plants fed upon by Gitellus washingtoni at Wallula, on the opposite side of the Columbia River. The squirrels have been reported to feed also on the leaves and seeds of sunflowers and the flowers of the bud sagebrush {Arte- misia spinescens) . They consume also grasshoppers, cicadas, and many other insects. When in contact with agricultural crops they be- come a serious pest, destroying alfalfa, wheat, barley, potatoes, beets, carrots, lettuce, and other garden vegetables. They were reported in 1917 to have practically destroyed a 10-acre field of beets at White Swan, Wash. EconomiG status. — This species was found by Francis (1922, p. 8) to harbor the infection of tularemia. SNAKE VALLEY GROUND SQUIRREL The Snake Valley ground squirrel {Citellus idahoetisis) has about the same habits as its near relative G. townsendii mollis. The squir- North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey PLATE 1 Q d z z sg is 0 = 1_ I = < H 111 . t-U Sj t ^ q: E q: d (/) Q ^i ss Oz Q 0 g? U) I 22 5^ 05 h i.^ !i^>/~vy»Rn; 1938] REVISION OF THE GROUND SQUIRRELS 7 rels inhabit the dry sagebrush plains and overflow into cultivated lands, where they prove destructive to crops of grain, alfalfa, and vegetables. They are reported to emerge from their hibernating dens in March, and by the middle of July they begin their period of estiva- tion. Each of four females taken at Nampa, Idaho, March 12, con- tained small embryos, numbering 8, 8, 9, and 10. WASHINGTON GROUND SQUIRRELS^" General habits. — ^AVashington ground squirrels {Citellus washing- toni subspp.) (pi. 1) occupy the dry prairies of the Columbia Basin, east of the Colmnbia Eiver. Vernon Bailey (in field notes) has described their habitat as follows : The country which they inhahit is open and either dry and sandy, grassy, or sagebrush covered. They are most numerous along steep hillsides, in gulches, and in sagebrush along river bottoms. On the smooth, grassy prairie they are common and more evenly distributed. They collect where some pro- tection is afforded by scattered bunches of sagebrush or Chriisotharnnus, but avoid any dense cover from which they cannot look out on all sides. Bailey estimated that in the section around Pendleton, Oreg., in 1896 these squirrels averaged 50 to 100 per acre in the colonies exam- ined. On a measured acre on the prairie adjacent to a wheatfield he counted 620 burrows in addition to 62 larger holes dug by badgers in their search for the ground squirrels. The distribution of the squir- rels, however, is not continuous, and over most of their range they are less abundant than this estimate would indicate. A burrow of tliis species at Attalia, Wash., after having been fumigated with carbon bisulphide, was partly excavated by Scheifer, who states: At a depth of 4:^-2 feet and a distance of 11 feet down slope from the entrance, two half-grown squirrels were found suffocated. At 17 feet down slope from the entrance the burrow had reached a depth of hVi feet, which level it fol- lowed 7 feet farther— 24 feet in all. No branch burrow or nest had been found. Scheffer found the Washington squirrels out of their burrows at Wallula, Wash., on January 25 (1926). They were oiit in numbers at Almota, Wash., on February 23. In mild seasons, single individ- uals often emerge from hibernation as early as January 9. The ma- jority are reported to enter estivation during July, but Scheffer found that all had disappeared from their known haunts at Wallula and Attalia by June 16 (1925), when the weather was dry and hot. A few were seen at Coulee City as late as July 31, and one at Water- ville. Wash., on August 4. The young are brought forth in February or early in March, and by the last of March they are able to run about and feed on ^reen food. The voice of the Washington squirrels is said to be very much like that of Citellus townserulii mollis — a soft, lisping whistle. When their suspicions are aroused, the squirrels stand up at full length on their hind feet and give their alarm note as they watch keenly for the appearance of an enemy. The alarm is then repeated on all sides by other members of the colony. Food hahits. — Bailey examined about 30 stomachs of this species at Pendleton, Oreg., and found the contents to be almost exclusively 2i> Formerly known as Townsend's ground squirrel (Citellus townsendii). For oxpla- nation of change of name see p. 70. 8 NORTH AMERICAN FAUNA [No. 56 of vegetable origin — green leaves, plant stems, wild flowers, bulbs, and seeds. Seeds of alfileria constituted over half of the food and were found in almost every stomach. Insects, consisting of a large caterpillar, a few small beetles, and several cicadas, were found in four stomachs. At Wallula, May 22 to 30, 1925, Scheffer studied the food habits of the Washington squirrels in detail, and made the following field notes : Examinations of the stomachs showed that they were not gorged to re- pletion with green stuff as they had been earlier in the season, but were filled to a more moderate degree with bits of succulent stems, buds, seed pods, and seeds. Plants on which they were observed to be feeding were globemallow (Sphaeralcea nmnroana), silver Indianwheat (Plantago purshU), downy chess {Bromus tectorum), slender wheatgrass (Agropyron pauciflorum) , Indian rice- grass (Orysopsis hymenoides), tumblemustard {Norta altissima), and to a limited extent, alfalfa, oats, and wheat. In every case the direct observations were supplemented by examination of the plants on the feeding grounds. In the case of the grasses both heads and stems were being used for food ; the favored part of the mallow seemed to be the small circular seed vessels, while only leaf tissue of the mustard appeared to be eaten. Economie status. — ^By reason of their great abundance and their fondness for grain, these ground squirrels rank as one of the most serious of agricultural pests. They extend their depredations well into the fields of growing grain, cutting down the stalks and eating only the tenderest portions, or at a later stage selecting only the fruiting heads. In some fields, in a strip around the edge two rods or more in width they destroy more than half the grain. They also invade gardens and feed on young cabbage plants, green peas, and young corn. RICHARDSON'S GROUND SQUIRREL General habits. — Richardson's ground squirrel {Citellus richard- sonii richardsonii) (pi. 2) lives on open prairies and on flats along the shores of lakes and rivers, seeming to prefer the sandy or gravelly ridges. In farming regions, the animals move into grainfields and pastures, and in some localities they occur in great abundance. Seton (1928,_p. 261) describes a colony at Whitewater, Manitoba, which he estimated to number 10 squirrels to the acre. He states, also, that at Carberry, Manitoba, in the early eighties, he often noted as many as 50 on a single acre, and captured 20 within an hour in two traps. At the approach of an intruder, they stand flat on the hind feet, the body erect entirely off the ground and the front feet hanging down on the chest. This habit has given the species the common name of "picket pin." When alarmed they whistle vigor- ously and when chasing one another they squeal loudly. In enter- ing their burrows, after halting at the entrance and lifting the head to watch the enemy, they go in head first usually switching the tail spasmodically. They quickly disappear with a final flirt of the tail, if danger still threatens. James Silver excavated and measured nine burrows of this species in North Dakota and found that the tunnels varied in length from about 12 to 49 feet and in depth below the surface from 3 feet 10 inches to 5 feet 8 inches. Most of these burrows contained a cavity 6 to 9 inches in diameter in which was a nest made of dry or green grass, straw, and oat hulls. North American Fauna No. 56, U. S. Dept. of Agriculture. Biological Survey PLATE 2 • ^-^ 1938] REVISION OF THE GROUND SQUIRRELS 9 Apparently the dates of entering and leaving the hibernation dens vary considerably with local conditions. Ranchers in central Mon- tana reported the squirrels as appearing in February, and Seton (1928, p. 264) quotes A. S. Barton in the statement that these squir- rels came out during February (1905) in the country around Boisse- vain, Manitoba. At Cando, N. Dak., they were first observed in 1915 on March 10. In Alberta, on April 6, 1920, Francis Harper noted them in numbers at many points along a railroad between Calgary and Wetaskiwin. In North Dakota, practically all the adults go into estivation in July, while the young remain above ground until September or later. At Waterton Lake, Mont., August 14, 1917, Vernon Bailey noted many burrows of this species but only a single animal, and thought that most of them had estivated on account of the drying up of the vegetation. At St. Mary Lakes, Mont., they were numerous and ac- tive on August 24. At Bismarck, N. Dak., most of the squirrels had denned up by September 1, but at Blackfoot, Mont., they were still numerous above ground on September 12, and at Van Hook, N. Dak., on October 16, one was seen out after a very cold night. K. F. Ebner, of Cando, N. Dak., made notes on the disappearance of these squirrels in the fall of 1914; he stated that during the sec- ond week in September they appeared only on pleasant forenoons, and if disturbed would go into holes and remain the rest of the day ; that after about October 1, they would remain in their burrows for 2, 3, and sometimes 4 days in succession, even in pleasant weather; and that none were seen from October 15 to November 2, but on the latter date they were unusually lively in the pasture. Richardson's squirrels produce but one litter a year, numbering from 6 to 11, with an average of 7.5. The period of gestation, as determined by U. S. Ebner, from specimens kept in captivity, is about 28 to 32 days. The young squirrels appear above ground at various times from April 20 to June 1. Ebner dug out a number of burrows in fall, without finding any store of food. The voice of this species is described as a short, shrill, whistling note. The animals are ordinarily not suspicious, and when taken young some make gentle and attractive pets, while others remain wild and vicious. Food hahits. — On the prairies, these squirrels subsist on the native grasses and flowering plants. They consume also seeds of various plants, including bindweed and sagebrush, and capture many grass- hoppers and caterpillars. Grainfields attract them and there they destroy quantities of grain, both in narrow strips along the edges and also around their burrows in the middle of the field. Follow- ing planting they dig up and eat the seed grain. Early in the sea- son they cut off and eat the succulent stems, and when the grain is ripening they pull down the stalks and cut off the heads. Seton (1928, p. 270) tells of finding in the pouches of one of these ground squirrels 240 grains of wheat and nearly 1,000 grains of wild buckwheat. He records also finding about 2 quarts of sprouted wheat in a squirrel's den that had been raided by a badger in fall. II Q NORTH AMERICAN FAUNA [No. 56 WYOMING GROUND SQUIRREL General habits.— The Wyoming ground squirrel {Gitellus richard- sonii elegans) inhabits the sage and greasewood plains, chiefly in the Transition Zone and partly in the Upper Sonoran. The annuals reach comparatively high elevations in sections where grass-covered flats occur on a gravelly soil, but in general they avoid wooded or brush-covered areas. In many localities their burrows cover the ground more thickly than prairie dog mounds, and the population has been estimated to average at least 20 squirrels to the acre. The burrows are usually more numerous bordering cultivated fields, or in grassy patches in the semidesert regions. In irrigated districts, these squirrels concentrate in large numbers along roadways, railway embankments, and irrigation ditch banks, where the burrows are safe from the irrigation waters. In the Green River Basin, Wyo., the first of these squirrels to emerge from hibernation were reported on April 2, and by April 12 they were out in great numbers. A female taken at Opal, Wyo., April 21, contained 5 small embryos. Burnett (1920, p. 8) records that 14 females examined in 1916 had an average of 8.2 young, and 19 examined in 1920 an average of 4,6. He states that the young are born about the middle of May. By the middle of August the squirrels are fat and ready to begin their long sleep underground. Bailey reports that at Meeker, Colo., most of the ammals had gone into winter quarters by August 10, though several were seen on August 12. At Lay, Colo., A. G. Wallihan reports that they retire about the middle of July. Food habits. — Stomachs of 5 adults examined at Elk Creek, Idaho, were largely filled with ripe fruit of Amelanchier alnifoUa, together with green foliage, flowers of a composite, seeds of grasses, and a few remains of grasshoppers. Two individuals taken in the Laramie Mountains, Wyo., had their stomachs filled with the blossoms of rabbitbrush (Ohrysothamnus) , and one taken at Cheyenne had its pouches full of the heads of grama grass. A specimen of C. r. neva- densis taken in Malheur County, Oreg., had its pouches filled with 1,160 fruiting capsules with seeds of Collomia. Economic status. — ^Wherever these ground squirrels come in con- tact with agricultural operations they become a serious pest. They consume large quantities of range grasses and in grainfields pull down the stalks and consume the heads of grain. They are especially destructive to growing barley and oats. Ranchmen in Moffatt County, Colo., claimed that in 1906 this species destroyed fully a third of the local rye crop and that they ruined a 5-acre field of oats in the same county. Carrots, radishes, lettuce, and other garden crops are sometimes damaged by these squirrels. Near Laramie, Wyo., a promising head-lettuce industry was threatened when the squirrels nibbled into the growing heads and so deformed them that an imperfect product resulted. Plague infection was demonstrated in a specimen of this squirrel taken in 1935 near Dillon, Mont. (Meyer, 1936, p. 964). UINTA GROUND SQUIRREL General habits. — ^The Uinta ground squirrel {Gitellus armatus) occupies dry meadows, pasture lands, and cultivated fields in high i North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey PLATE 3 1938] REVISION OF THE GROUND SQUIRRELS H valleys, and ranges in the mountain meadows nearly to timber line (Wind River Mountains, Wyo., 10,500 feet). The animals seem to prefer moist locations near water, especially where the vegetation is rank. They live in large colonies in burrows dug in soft soil in the meadows or along irrigation ditches. Occasionally they climb into bushes. Their voice is said to be louder than that of C. elegans; their call is described by Merritt Gary as "a sharp, vibrant, bird-like Avhistle, often terminating in a trill." According to O. E. Stephl, they have another call, consisting of three distinct notes, repeated rather slowly. Like some others of their tribe, they spend only about 5 months of the year above ground, the remaining period being spent in estivation and hibernation. In Yellowstone Park, nearly all the adults disappear by the middle of August and by the end of that month only an occasional immature individual is seen above ground. A very late record is that of a specimen collected at Mammoth Hot Springs, Yellowstone Park, October 4 (1902). The first to come out in spring appear usually from about April 5 to 11, though occasionally one may be seen as early as March 17. Food habits. — Little of a definite nature is on record concerning the food habits of this species, but reports of field collectors show that, like other related species, these ground squirrels feed on green vegetation and dry seeds. Stomachs of 10 specimens examined by A^ernon Bailey in Star Valley, Wyo., were full of green herbage, flowers of rabbitbrush {Chrysothamnus) , and seeds of grasses and other plants. Two contained some golden currants (Rlbcs aureum) . That these squirrels relish meat is evidenced by Bailey's statement that they ate two pocket gophers caught in his traps. Living chiefly in mountainous country, the Uinta ground squirrels come in conflict with agricultural interests less frequently than do many of the other species, but wherever their range extends into cultivated valleys, they damage crops to some extent. Plague has been demonstrated in specimens of this squirrel taken in Bonneville County, Idaho, in 1936 (Meyer, 1936, p. 965). BELDING'S GROUND SQUIRREL General habits. — Belding's ground squirrel {Citellus beldingi beldingi) (pi. 3) inhabits mountain meadows near timber line in the Sierra Nevada and is only rarely found in open timber or brush lands. Their burrows are dug beneath stumps, logs, or rocks, or sometimes out in an open meadow, and frequently they appropriate the tunnels of pocket gophers {Thomomys) for their own use. The period of hibernation in this species is not definitely known but evidently in the high mountain meadows these squirrels are able to obtain an abundance of green food all summer and consequently they remain active considerably longer than do other species living in the dry valleys at lower altitudes. Grinnell and Dixon (1918, p. 6G4) report these squirrels numerous in Tioga Pass, Calif., on September 28 and some out as late as October 7 near Ten Lakes, Yosemite Park. At Lake Tahoe, J. A. Loring found them out in numbers on May 18. Grinnell and Storer (1924, p. 173) mention a specimen obtained at the Farrington ranch, near Williams Butte, on April 29, 1916. The young are born about the first of July. 12 NORTH AMERICAN FAUNA [No. 56 The voice of this species is said to resemble that of the Oregon ground squirrel, according to Grinnell and Dixon (1918, p. 662) — The usual call of warning consists of a series of from five to eight short shrill whistles uttered in quick succession and weakening toward the last. F'emales warn their young when foraging abroad with -a lower-pitched, double note, or bark, e-chert. A single note, sirt, is also frequently heard. Food hahits. — Belding's ground squirrel feeds largely on the stems and seeds of wild grasses. C. Hart Merriam reports the species eating the flowers of beardtongue {Pentstemon confertus). Edmund C. Jaeger (1929, p. 91), writing of these squirrels as observed in July near Bishop Pass, Calif., says : Their principal food at this time was the half-ripe seeds of a phacelia, the fruit of which was borne on stout stems about seven inches from the ground. In Long Valley, Mono County, A. Brazier Howell (1924, p. 33) found them feeding extensively on a species of cicada {Okanagana magnifica) . C. Sharsmith (1936, p. 12) records instances where these squirrels had killed a junco, an Audubon warbler, and a chipmunk. Since the range of Belding's squirrel lies above the zone of agricul- ture, the animal is of no special economic importance. OREGON GROUND SQUIRREL General habits. — ^The Oregon ground squirrel {Citellus heldingi oregonus) lives chiefly in mountain meadows but also in pastures, meadows, and grainfields in the valleys, and to a less extent in open pine forests. It avoids marshy ground as well as rocky or brushy slopes. It lives in large colonies, especially on ranches where food is abundant. Ira N. Gabrielson reports a count of 466 on a 2-acre tract in Klamath County, Oreg. On a ranch in Butte Valley, Calif., Grinnell and Dixon (1918, p, 654) estimated 560 burrows on 1 acre. One burrow they excavated was 66 feet long, including the various windings and its branches ; its greatest depth below the surface was 45 inches. These squirrels are almost exclusively ground dwellers ; very rarely have they been observed to climb into bushes to obtain seeds. Their voice is described by Bailey as "a rattling chipper., or series of sharp chips so rapidly uttered that they almost blend into a prolonged trill." Hihernation. — The Oregon ground squirrel spends more than half the year in a dormant condition. The date of entering hibernating quarters varies with the dryness of the summer and the supply of green vegetation. During some seasons, in the valleys, most of the squirrels disappear by July 10, but in seasons of greater rainfall they remain out several weeks longer; in the mountains, small numbers may be seen above ground as late as the first of September. In spring they begin to appear about the middle of February and by the first week in March are usually out in force, even if obliged to burrow through a foot or more of snow to reach the surface. At low altitudes in Umatilla County, Oreg., some have been reported out as early as January 22. Breeding. — This species produces one litter of young a year, vary- ing in number from 4 to 12, with an average of about 8. The young, born about April 10 to 20, appear above ground about May 10. In Butte Valley, Calif., on May 16, Grinnell and Dixon (1918, p. 658) report young out of the burrows in numbers, all about one-fourth to one-third grown. North American F auna No. 56, U. S. Dept. of Agriculture, Biological Survey PLATE 4 « **:. *^^ \W 1938] REVISION OF THE GROUND SQUIRRELS 13 Food hahits. — The food of the Oregon ground squirrel consists mainly of green vegetation. In addition to grasses and cultivated grain, the following plants have been identified in the stomachs or cheek pouches : Flowers, stems, and leaves of camas ( Quamasia qua^ mash)^ buttercup {Ranunculus)^ springbeauty {Claytonia), shoot- ingstar {Dodecatheon) ^ mule-ears (Wyethia atnpIexicauJis) , sage- brush, and alfileria. Grasshoppers, crickets, and other insects are eaten by the squirrels, and 18 caterpillars from one stomach were recorded by Bailey. The squirrels have been reported to catch and kill young chickens and to devour their own kind found caught in traps. Economic status. — Grinnell and Dixon consider this species second in economic importance in California to the California ground squir- rel; they point out that these squirrels occur in great abundance in the grasslands and do serious damage to range grasses. Also, in some sections, they inhabit fields of alfalfa and grain — wheat, oats, and r3'e — and destroy a large proportion of the crops. This species has in recent years been found to carry bubonic plague. Surveys made during the summer of 1934 in Modoc County, Calif., resulted in finding the disease in 5 percent of the squirrels shot or found dead in an area of 65,000 acres. In April 1935, plague was proved in 107 Oregon ground squirrels (7 percent of 1,492 squirrels shot) in Modoc County. A fatal case of human plague occurred at Lakeview, Oreg., in May 1934, probably contracted from a ground squirrel of this species (Meyer, 1936, p. 964) . COLUMBIAN GROUND SQUIRREL AND RELATED RACES General hahits. — The Columbian ground squirrel and related races {Gitellus columhianus subspp.) (pi. 4) live in a wide variety of habitats, from the open prairies of eastern Washington to the moun- tain parks at an altitude of 7,000 or 8,000 feet. Apparently the animals prefer rough, rocky, half-forested hillsides, but in many places they are numerous in hay meadows, grainfields, stony pastures, and open pine flats. They live in colonies but are somewhat less gregarious than prairie dogs. They spend the greater part of the daylight hours gathering and consuming food from an area rather close about their burrows, seeking safety in their dens when danger appears, but if the food supply is limited near their dens, they often make somewhat extended trips in search of some favorite item. These squirrels are rather noisy, and in a colony their alarm note — a clear, sharp chirp., repeated a number of times — is almost con- stantly heard from sunrise to sunset. In places where they are per- secuted by man and also in wilderness areas remote from civilization they are usually shy and are difficult to approach closely. When given protection, however, as in some of the national parks, they become so tame that they will take food from the hand. Burrows and nests. — The burrows of these squirrels are dug be- neath logs, stumps, or boulders and descend at an angle of about 45°. Vernon Bailey (1918, p. 47) describes a summer den that he ex- cavated near Piegan Pass, at 7,000 feet altitude in Glacier National Park, Mont., as follows : The mound at the entrance of the burrow contained about 4 bushels of earth and stones brought from the burrow, and the lower part was packed and hard as though an accumulation of several years. Tliere were two other openings 14 NORTH AMERICAN FAUNA [No. 56 farther back from which no earth had been thrown and evidently they had been tunneled to the surface from below. The main shaft of the burrow was usually 3 or 4 inches in diameter, and back a couple of feet from the entrance, just before the burrow forked into two main shafts, was a roomy chamber where the squirrels could turn around and sit up comfortably, a sort of reception room. Near secondary forks were also two other chambers which may have served several purposes, such as convenience in storing earth brought out of the tunnels, or places of retreat from which to watch for enemies that might enter the burrow from either direction. Well back about 8 feet from the entrance and a foot below the surface of the ground was a large nest chamber about a foot in diameter nearly filled with old soft nest material. The nest was composed almost entirely of the soft flat leaves of the brown "glacier grass" (Juncoidcs parviflorum) which abundantly covers the mountain slopes. At the bottom it was damp and moldy, but from the bed in the center to the top it was dry and clean, and a few fresh, green blades had been brought in for food or nest material. It had evidently served as winter quarters for the old squirrel and as a nest for her young and was being prepared for the coming winter. From one side of the nest chamber the burrow led down to an older and deeper chamber of some previous year, containing at the bottom an old rotten nest half full of excrement. A tunnel ran from it back toward the main entrance and into the main tunnel near the middle, making an easy way of escape if an enemy should dig to the first nest. Back of the nest a small shaft led to the surface of the ground and another opened out at the end of the first main fork of the tunnel. These rear openings were half concealed in the grass and evidently were for use as avenues of escape in case the burrow should be entered by a weasel or dug out by bear or badger. Estivation and hibernation. — This species spends from Y to 8 months annually in a dormant condition. Those individuals living in the valleys and on the prairies become very fat by midsummer, and from July 15 to 30 a noticeable decrease in their numbers is ob- served as some of them enter estivation. In eastern "Washington, in dry seasons by July 29 and in wet seasons by August 11, all have entered their dens for the long sleep (Shaw, 1925a, p. 75). These squirrels do not as a rule drink water, but depend upon succulent vegetation to supply needed moisture. Apparently the date of be- ginning estivation is determined chiefly by the ripening of the vege- tation and consequent reduction of the moisture content in their food, and in part also by the accumulation of fat in the body. At Osborn, Idaho, the last of the ground squirrels disappeared following a first frost on August 8 (1895) . In the Bitterroot Valley, Mont., all had begun estivation by August 25 (1909). In the moun- tains, at higher altitudes, some of the animals remain out until the first week in October (Woodman Creek, west of Lo Lo, Oct. 7) . A single individual was taken near Kalispell, Mont., on October 1 (1932). At Pullman, Wash., the first squirrels came out of their hiberna- tion dens on February 21 (1913), March 1 (1912), and March 8 (1911 and 1917). At Endicott and St. Johns, Wash., they first appeared from February 2 to 9 (1909). In the Bitterroot Valley, Mont., the first were seen on March 6 (1910), and March 25 (1912), and by March 31 they were out in full numbers. The hibernation dens have been studied and described by W. T. Shaw (1925b, fig. 2, opp. p. 58), who states: A hibernation den is frequently a part of an ordinary den shut or sealed off from the main den by having all connecting burrows very effectiially plugged. It may, however, be quite remotely hidden away from the large summer den. Of 50 hibernation cells measured, the average depth below the surface was found to be 2 feet 6 inches; the shallowest cell was 6 1938] REVISION OF THE GROUND SQUIRRELS 15 inclies below the surface, the deepest 4 feet 11 inches. Occupied dens are sealed by the squirrels with a plug of earth 2 feet or more in length, tamped in. For most of the hibernation dens (except those on a side hill) drainage is provided to carry water away. In some cases an exit shaft leading toward the surface is provided. When ready to come out in the spring the animal digs its way to the surface, placing the soil removed in the bottom of the burrow, thus leaving no loose dirt at the entrance. Storage of food. — Food supplies are stored in the hibernation dens to a limited extent. Regarding this habit, Shaw (1925b, fig. 11, opp. p. 79) writes as follows: Very unexpected iufonnatiou has been found in connection with the matter of the food supply being stored for the winter. The nests of female and imma- ture squirrels are almost without exception lacking in a store of food. The uests of the old males, on the other hand, very frequently, though not always, have a cache of some kind of food. Strange to say, in this stored supply they seem to prefer some wild seed or bulb to grain, and nests found in wheat fields are frequently stored with some wild seed. Furthermore, they usually use but the one kind of seed, or bulb, in a nest at a time, though several kinds of seeds and bulbs have been found in the various uests discovered. In this connection it is interesting to note that the old male squirrels appear a week to 10 days before the females and immature, often when the weather is bad and food scarce, hence the need of food. It is also of interest to note that the store, which is found in the mulch or bottom of the nest, seems not to be touched during the winter, as several interesting observations tend to show, but is reserved until the time of awakening in the spring. Breeding. — The number of young in a litter varies from 2 to 5, rarely 7, averaging about 3.5. The gestation period, as determined by Shaw (1925d, p. 108) from animals kept in captivity under semi- natural conditions, is 24 days. The rutting season begins about March 15 to 20, and Shaw records capture of a wild adult at Pullman, Wasli., on April 6, carrying G fully formed embryos. At Ford, Idalio, James Silver examined 25 females on April 10 that were carrying large embryos ; on April IG, 13 females showed evidence of having recently borne young. Probably in the mountains most young are born early in May; at Nyack, Mont., however, a female was captured on June 24, 1895, carrying 3 embryos. The young are able to leave the nest in about 4 weeks after birth. At Pullman, young were first observed out of their dens between May 4 and 10. Food habits. — The food of the Columbian ground squirrel com- prises a great variety of vegetable substances and a small proportion of animal matter. A large part of the vegetable food consists of wild and cultivated grasses, herbs, and fruits, including the bulbs of camas, wild onion, and glacierlily {Erythronium grandifiorum) ; stems, leaves, and flowers of false-hellebore (Veratrum), buttercups, roses, dandelions, mule-ears (Wyethia) , balsamroot (Balsamorhisa) , camas {Quamasia quamash).^ lupine, and wild lettuce; currants, gooseberries, strawberries, and serviceberries (Amelanchier) . On cultivated lands the squirrels consume the stems and heads of clover, alfalfa, bluegrass, oats, rye, wheat, and barley ; vines of pota- toes, beans, and peas ; lettuce, carrots, and probably other vegetables. Grasshoppers, cicadas, and caterpillars are frequently eaten, and sometimes fish, if the habitat borders a lake. Economic status. — Wherever it comes in contact with agriculture the large Columbian ground squirrel is destructive, particularly to -j^g NORTH AMERICAN FAUNA [No. 56 grain, clover, and pasture. When uncontrolled, the animals become numerous and may destroy practically entire crops in the area where they are living. Shaw (1925g, p. 264), writing of the section around Pullman, Wash., says: During 7 successive years, 7,000 squirrels were trapped on 416 acres of the college farm, or 2.4 squirrels per acre each year. A successful wheat raiser near Steptoe, V/ash., trapped 1,200 squirrels on 200 acres in 1 year, or 6 squirrels per acre. Shaw's experiments showed that single animals kept in confine- ment under natural conditions in the course of a season destroyed, on an average, 50l^ pounds of winter wheat. This species has been shown to be in large part responsible for the dissemination of Rocky Mountain spotted fever, Birdseye (1912, p. 10), reporting on his studies in the Bitterroot Valley, Mont., says that it is undoubtedly the most important host of the two younger stages of the fever tick, and is almost always infested with ticks Avhen occurring in suitable country. Plague infection was demon- strated in specimens of this species taken in Wallowa County, Oreg., in 1935 (Meyer, 1936, p. 964). PARRY'S GROUND SQUIRREL AND RELATED RACES General habits. — Richardson (1825, p. 319), writing of Parry's ground squirrel {Gitellus parryii 'paiTyii) as observed on the Arctic coast between the mouth of the Mackenzie and Bathurst Inlet, says : The gray Arctic marmot is common in stony barren tracks, but delights chiefly in sandy hillocks, amongst rocks, where it burrows, living in society. Anderson (in Stef ansson, 1913, p. 510) , writing also of the Arctic coast in the same region, says that these squirrels Avere found at many points along the coast in sandy clay hills and were particularly abundant in sandy alluvial river bottoms. Along the Mackenzie River, below Fort Good Hope, E. A. Preble found the animals liv- ing in burrows in the clay banks, well above high- water mark. On the Barren Grounds near Cape Eskimo, Hudson Bay, he found them occupying gravellj^ ridges, either old shore lines, or deposits left in the process of glaciation, and around Artillery, Clinton-Colden, and Aylmer Lakes, Seton and Preble (Seton, 1911, p. 342) found them frequenting similar situations. In McKinley Park, Alaska, O. J. Murie reported the subspecies G. 'p. plesius numerous in the valleys, on the slopes, and on the ridges. Some had dug their burrows among willows and in vegetation on the slopes, and others lived among rocks. A burrow dug out there was found to have two entrances and many ramifications; its greatest depth was 27 inches. In the Delta River region he found the squir- rels inhabiting the river bars and the flats among the dwarf birches and willows, as well as on the hills where cover was scarce. In northern British Columbia, Preble found them in broad nearly level valleys clothed with shrubby vegetation, or on the gentle lower slopes of mountains, and seldom or never above timber line. Richardson speaks of the alarm note of this species as "a kind of a whistle", and when the animal is in terror this note is said to re- semble the sound of a watchman's rattle. HibernaMon. — R. M. Anderson (in Stefansson, 1913, p. 510) states that on the Arctic coast, most of these squirrels go into hibernation 19381 REVISION OF THE GROUND SQUIRRELS 17 the latter part of September, though a few remain out until the middle of October ; and that they reappear in spring about the middle of April. At Collinson Point, however, on October 2, they were out in some numbers, and at Point Barrow individuals have been taken on October 15, November 10, and December 3. At Wiseman, on the south slope of the Endicott Range, two ground squirrels were seen by O. J. Murie on October 23 (1924). At Cold Bay, the Alaska Peninsula race {G. p. ablusus) was active in some numbers as late as October 18 (1902) (Osgood, 1904, p. 32), and at Togiak, Alaska, a specimen was collected on March 10 (1897). At Chignik, Alaska, during the mild winter of 1911-12, the squirrels were seen occasionally throughout the winter and a specimen was captured on February 13. The small mountain form {G. p. plesius) was observed at Teslin Lake, Yukon, on October 3 and specimens were taken in the Tanana Hills, Alaska, on March 4. Breeding. — Richardson (1825, p. 318) records taking a female that contained seven embryos at Pomt Lake, Mackenzie, on June 13. Judging from the size of two young individuals taken at Old Fort Good Hope, Mackenzie, it seems probable they were born about the middle of May. Echnund Pleller recorded a female of G. p. plesius suckling young on June 10, and another carrying a single large embryo on June 11, at Telegraph Creek, British Columbia. Food habits. — Richardson (1825, p. 319) reported the food of Parry's ground squirrels to be entirely of vegetable origin. He says : In upwards of 50 individuals examined at various periods, no animal sub- stance was detected in the pouches or stomachs. At Point Lake in lat. 65°, their pouches were observed about the middle of June to be filled with the berries of the Arbutus alphia and Vaccinium vttis-idaea, which were just then laid bare by the melting of the snowy covering, under which they had Iain all winter. In the end of July, on the shores of the Arctic Sea, their pouches contained the seeds of a Polygonum, and in Five Hawser Bay in September, they were filled with the seeds of astragali. At Aylmer Lake, Seton (1911, p. 237) obtained a ground squirrel with its cheek pouches full of mushrooms. Anderson (in Stefansson, 1913, p. 510) states that along the Arctic coast, the squirrels fed mainly on the roots of various species of Polygonum. The stomach of a specimen of G. p. ablusus, taken on Unimak Island, Alaska, May 8, 1925, and examined in the Biological Survey, con- tained the following materials: 21 caterpillars and lepidopterous pupae, 60 percent; 1 tipulid larva and 5 Bibio larvae, 4 percent; 2 beetles {Gryobius sp.) ; 1 ichneumonid and a spider, trace; 2 berries {Vaccinium sp.), 2 percent; a few leaves of Empetrum nigrum and other vegetable matter, 34 percent. YUKON VALLEY GROUND SQUIRREL General habits. — Osgood (1900, p. 31) describes the habits of the Yukon Valley ground squirrel {Gitellus osgoodi) as follows: From Fort Selkirk, near the limit of Spermophilus plesius in the interior, nearly to Circle, we saw no signs of ground squirrels of any kind. Just before reaching Circle, however, we began to see unmistakable signs of them and were soon attracted to a small colony by their clicking calls which reached our eai-s as we floated down in midstream. The call is executed in about the same time as that of 8. plesius, but its pitch is much lower and its effect on the ear is 154970—38 2 Ig NORTH AMERICAN FAUNA [No. 56 utterly different. It suggests the click of castanets. On going ashore we found their burrows and connecting paths scattered over quite an area on the hillside. The colony occupied the open hillside and a few ledges of loose rock, and even extended down into a thicket of alder and willow at the foot of the hill. The animals were very shy and became much excited at our approach. Their long tails were very noticeable in marked contrast to the short ones of 8. vlesius, which we had been accustomed to seeing. Writing of his second trip down the Yukon, Osgood (1909, p. 22) writes of these ground squirrels as follows : Many of their burrows are made in the sandy banks of the river, often only 3 or 4 feet above high-water mark, and usually open under the overhanging turfs of the bank or among the exposed roots of trees and shrubs. Higher up they are variously situated on the hillsides, where the little boreal sagebrush {Artemisia frigida) flourishes. As a rule, however, the hillside burrows are not in exposed places, but are more or less sheltered by small bushes near the edge of the timber. The animals were rather quiet and seldom gave their clicking cry except when alarmed. They fought viciously when being taken from traps, often lunging at vis with mouth open and claws spread. Several were seen at the water's edge, and tracks were abundant on the damp sand, but whether or not they drink there was not ascertained. Nearly all the females taken had the mammae distended with milk. Apparently most of the young were too small to leave the burrows. At one place 5 little squirrels all of a size and evidently from the same mother were caught in rapid succession. Of these, 4 were normal in color and the fifth was in the black phase. Among adults the black phase was found in about the same proportion. STRIPED GROUND SQUIRRELS General habits. — The striped ground squirrels {Gitellus tridecem- lineatus subspp.) dwell chiefly on dry grassy prairies and to a less extent in sandy river bottoms and the brushy borders of tmiber tracts. They are gregarious only to a slight extent, and not at all sociable, individuals usually living a more or less solitary life and often digging a number of burrows, some of which are shallow and are used for temporary shelter and others of more elaborate con- struction for more permanent use. These latter are ordinarily in the hard soil of upland pastures or meadows and are said always to have two entrances. They descend steeply for a short distance, then extend horizontally. They may be as much as 20 feet in length and from 4 to 46 inches in depth. Usually there is no earth piled around the entrance, the rim of the burrow being level with the surface and thus quite inconspicuous. Frequently the burrows are plugged with earth by the squirrels after entering, especially during hibernation. Sometimes abandoned burrows of other rodents are used, including those of prairie dogs, kangaroo rats, and pocket gophers. Nests of dry grass of a spherical shape are found usually in the longer permanent burrows, at depths varying from 3 to 29 inches (Johnson, G. E., 1917, p. 264). The nests are used in spring to house the young, in summer for storage of food supplies, and in winter for hibernating quarters. Breeding activities are at their height during April, and the young, numbering from 5 to 13 (commonly 6 to 10), are brought forth ordinarily in May or early in June. The gestation period is given by Wade (1927, p. 271) as between 27 and 28 days. The note of this species is described by Bailey as "a rapid bird- like trill or trembling whistle — a long drawn-out chur-r-r-r-r in a high key." 1938] REVISION OF THE GROUND SQUIRRELS 19 Hibernation. — The date of entering on the winter sleep varies with season and locality. At Lincoln, Nebr., Wade (1930, p. 169) re- gorted that in 1927 nearly all had disappeared by the first week of eptember, while in 1926 they remained out much later, small ninn- bers being seen until October 17, when the last one was noted. In Colorado, according to Burnett (1914, p. 6), the latest date recorded is November 9, and the earliest date in spring, March 23. Other late fall dates are: October 30 (Illinois), November 3 (Springer- ville, Ariz.), and November 23 (Oklahoma). Wade (1927, p. 270) states that in the vicinity of Lincoln, Nebr., these squirrels emerge from hibernation between the middle of March and the first of April; in 1926 the first were seen on March 17. Near Minneapolis, Minn., they were reported to appear 1 year on March 17 and 2 years on April 5. In southern Manitoba, accord- ing to Seton, they may come out as early as March 27, or in back- ward seasons as late as April 20. Johnson (Johnson, Foster, and Coco, 1933, p. 266) states that in west-central Kansas the males appear in numbers above ground usually about the middle of March and the females about the last of March or first of April. Food habits. — The striped ground squirrels feed on a variety of wild plants and seeds, in addition to cultivated grains, and are especially fond of grasshoppers and other insects. Bailey (1893, p. 39) has given an extended account of the food of this species, in which he shows that more than half the contents of 80 stomachs examined consisted of insects, including grasshoppers, crickets, caterpillars, beetles, ants, and insects' eggs. The A^egetable matter comprised oats, wheat, cactus fruit, nightshade berries, roots, herb- age, and seeds of goosefoot {Ghenopodium)., knotweed {Polygo- num)^ and sunflower {Helianthus). Eleven cheek pouches of this species examined contained only seeds, including wheat, oats, millet, deervetch {Lotus), and seeds of porcupine grass {Stipa spartea), sunflower, gromwell {Lithospermum) , bristlegrass {Setaria), Pani- cum, ragweed {Ambrosia), and black locust {Robinia). To the list may be added cotton, clover, and flax seed, wild beans, and seeds of dandelion, vetch, ricegrass (Oryzopsis), gum weed {Grindelia), and the buffalo-bur {Solarium rostratum). Morris M. Green (1925, p. 176) records the capture of a striped ground squirrel that had its cheek pouches bulging with 196 large seed pods of the sleepy catchfly {Silene antirrhina). Much of the dry food gathered by these squirrels is stored in their burrows; concerning this habit, Kennicott (1857, p. 77) writes: Many of our farmers suppose that this animal feeds, in winter, upon stores of provisions laid up in its hole for that season; for, though it spends the winter in a state of profound torpor, it collects food in its hurrow. This is done in spring and summer, as well as in autumn. Considerable stores of grain, seeds, roots, &c., are found thus collected, in large sidechambers exca- vated for their reception in the burrow. Corn, wheat, and oats are stored up, when taken from the newly-planted fields in spring, with buckwheat and winter wheat later in the season, as well as heads of grain taken from the edges of the fields in harvest time. I have seen more than a quart of crab- apples taken from the burrow of one which had carried them several rods from a tree. George and Frank Kennicott inform me that they observed one, the burrow of which was near a lone burr-oak, on the prairie, to carry great quantities of acorns into his hole ; and another was killed by them, the cheek- pouches of which were crammed with the dry ovaries of a prairie plant, the seeds of which were exceedingl.v minute. From this, it would appear that the 20 NORTH AMERICAN FAUNA [No. 56 striped spermophile at all seasons carries portable articles of food to its bur- row to be eaten. He certainly takes no food from the time lie first becomes torpid, in autumn, until be again becomes active late in the following spring. Johnson records a burrow of this species in which the nest cavity was entirely filled with imshelled oat kernels, estimated to number about 23,000, and another burrow that contained- 2,000 or 3,000 wheat kernels. This species shows a rather decided taste for flesh food, and it has several times been reported to capture and kill mice (Bailey, V., 1893, p. 38), and small chickens (Bailey, B., 1923, p. 129; Green, 1925, p. 175), and even to feed on the bodies of its own kind. Econotnic status. — The most serious charge against these ground squirrels is that they dig up and destroy newly planted corn. Wliere the squirrels are abundant, this habit may result in serious damage to a crop but ordinarily the depredations are confined to a few row,s on the edge of a field. Peas, beans, cucumbers, squashes, beets, straw- berries, and other garden crops are sometimes damaged, and fields of wheat or oats are occasionally drawn upon for supplies to be stored in the burrows. Against these destructive tendencies must be placed the evident fondness of the squirrels for grasshoppers, cutworms, webworms, and other injurious insects, the destruction of which undoubtedly exercises an important check on the ravages of the pests. Wherever the squir- rels occur on extensive grasslands they are distinctly beneficial, MEXICAN GROUND SQUIRRELS General ha'bits. — The Mexican ground squirrels {Citellus mexi- canus subspp.) inhabit sandy plains where there is a growth of cactus or mesquite, and both in Mexico and the United States they range out into cultivated fields of corn or other grain. Their burrows, usually situated at the base of mesquite or other bushes or on the edge of a bunch of cactus, descend nearly perpendicularly for a foot or more, then slope down at an angle still deeper. Apparently these squirrels do not hibernate, but they have the habit of plugging the entrance to their burrows after going in, and during cold weather they may remain under ground for considerable periods. Th&y are shy and usually silent, but Nelson states that they have a shrill, whistling note of alarm. Food ha'bits. — Bailey (1931, p. 115) reports this species feeding in about equal proportions on seeds and insects. Mesquite beans and seeds of Acacia are said to be favorite foods and doubtless many other seeds are eaten. At Langtry, Tex., Gaut found the squirrels feeding on the purple blossoms of a groundcherry {Physalis lobata) . They often range into cultivated fields and do considerable damage in spring by digging up corn, melons, beans, and sweetpotatoes, and later by eating ripening grain. SPOTTED GROUND SQUIRRELS General ha'bits. — The spotted ground squirrels {Citellus spilosoma subspp.) (pi. 5) seem to prefer dry, sandy soil for their habitation. They live in drifted sand along river flats, in grassy parks, in open pine forests, and to a less extent on rocky mesas. Their burrows North American Fauna No. 56. U. S. Dept. of Agriculture. Biological Survey PLATE 5 ■^. ''/ 'I; i% A ^^m-J i 1 M B i 1, 1 ^ . •■* 1 1938] REVISION OF THE GROUND SQUIRRELS 21 are usually under a bush, in a weed patch, or under an overhanging rock. D. E. Lantz dug out a burrow at Hugo, Colo., that had three entrances and was about 12 feet in length, though nowhere more than 18 inches below the surface. It terminated in a small, rounded chamber in which was a slight nest of grass. In some localities the squirrels often appropriate the burrows of kangaroo rats or other rodents. Like most of the ground squirrels, they are strictly diurnal, but are rarely seen abroad during the heat of midday. They are shy and retiring and of gentle disposition, and when captured alive make attractive pets. Vernon Bailey describes their call note as "one long, bubbling, birdlike whistle." These little squirrels do not wander far from their burrows, and in running their movements somewhat resemble those of a lizard; the body is more or less flattened, the tail is held close to the ground, and the squirrel proceeds by short runs with frequent stops. Hibernation. — Hibernation in this species is apparently not com- plete, at least in the more southern parts of its range, but during severe winter weather the animals usually remain within their bur- rows. Specimens have been taken near Tucson, Ariz., from January 27 on through February and March; at El Paso, Tex., February 9, 20, and 21; in Lake Valley, N. Mex., November 13; at Deming, N. Mex., December 4 and 6; and at Chihuahua, Mexico, December 25. Food habits. — The food of these ground squirrels is largely green vegetation and seeds. The following items have been identified in their stomachs : Cactus pulp, mesquite beans, seeds of saltbush {Atri- plex)^ sandbur {Cenchrus)., sunflower, gourd, and iris; grasshoppers and beetles. Living mostly in uninhabited regions these squirrels are of little economic importance. They undoubtedly consume con- siderable grass and in cultivated areas are sometimes troublesome in digging up planted seeds, PEROTE GROUND SQUIRREL General habits. — Little is known of the habits of the Perote ground squirrel {Citellus jyerotensis) . Nelson reported that it lives in the plains, about the borders of wheatfields and cornfields. FRANKLIN'S GROUND SQUIRREL General habits. — Franklin's ground squirrel {Citellus frankUnii) (pi, 6) or the "gray gopher," as it is frequently called, inhabits prairies, bushy pastures, grainfields and hayfields, open groves of timber, and partly dry marshes, Kennicott (1857, p, 79), writing of its habits in Illinois, says : It is observed to inhabit the thickets of low bushes, and the edges of the timber, more than the other [C. tridecemlincahis], but does not occur in the woods. It is fond of digging long burrows in the banks of ditches, and several times I have seen it living in steep river banks, as well as under small wooden culverts in roads. It is not so shy as the striped spermophile, and takes up its residence quite near dwellings. Wood (1910, p. 528), writing from Illinois half a century later, says of these squirrels : At present a necessary condition for their habitation seems to be the presence of some shelter, such as may he furnished by tall grass, or a field of clover, alfalfa, or grain. Others have noticed that when the crop on such a field is cut 22 NORTH AMERICAN FAUNA [No. 56 the gophers leave, at least for a while, and my own observations coincide with theirs, though I have known the gophers to return to the same spot after the second crop of alfalfa had started. They avoid closely cropped pastures, well-kept cemeteries, lawns, and similar places where the striped gopher is especially abundant, yet ev^en in such localities I have found them congregated under a heap of compost. In fact such a shelter seems to have special attrac- tions for them, as noted by Bailey. ... The species is decidedly gregarious, nearly always being found in colonies. As their burrows each have several openings and these are conspicuously marked by the dirt thrown out, a colony becomes a great nuisance in a hay or grain field. The conspicuousness of these burrows and of the animals themselves has aroused the animosity of the farmers and hastened the de- struction of the gophers. Kennicott (1857, p. 80) describes their notes as "a remarkably clear whistle twitter, more musical than the voice of any other mammal I ever listened to, and as clear as that of a bird." HibemoMon. — Franklin's ground squirrel has been known to store up in September as much as half a peck of oats in a burrow under a shock. The animals, however, become excessively fat in fall and all retire to their burrows in October, where they remain in hiberna- tion imtil April. Bailey (1893, p. 52) gives dates of their appear- ance at Bathgate, N. Dak., as April 3 (1889) and April 21 (1890). Kennicott states that they have been found hibernating under piles of rails and in corn shocks, and in two instances in a hay stack. Eemington Kellogg states that he has found the animals torpid in a burrow about 3 feet underground. Breeding. — The young, 5 to 10 in a litter, are born in May or June; by the last of July, in North Dakota, they are out of their burrows foraging for food. Adults carrying embryos were taken at Elk River, Minn., on May 7, and at Carberry, Manitoba, on June 15. Food habits. — The vegetable food of this ground squirrel comprises about two-thirds of the total and includes clover, timothy, junegrass; leaves of plantain, mustard, and probably other wild plants ; wheat, oats, barley, newly planted corn* seeds of needlegrass (Stipa), cockle- burs, and basswood; strawberries and nightshade berries. Animal matter, found in 29 stomachs examined in the Biological Survey, consisted of beetles and their larvae, caterpillars, grasshoppers, crickets, ants, eggs of insects, and feathers of a small bird (Bailey, 1893, p. 55). Individuals of this species have been known to kill and eat wild mice and a young rabbit, to rob a meadowlark's nest, to kill a wood pewee, to capture small chickens, and to eat hens eggs. Economic status. — ^In localities where these squirrels are abundant, they may do considerable damage to crops by digging up newly planted corn and in the fall by burrowing under corn shocks. They sometimes invade vegetable gardens and destroy peas and cabbage, and in grainfields they destroy considerable grain in the vicinity of their burrows. ROCK SQUIRRELS General habits. — The several races of the rock squirrels {Citellus variegatus subspp.) (pis. 7 and 8) have habits similar to other ground squirrels; all show such a decided preference for inhabiting rocky canyons and rocky mountain sides that their name "rock squirrel" seems quite appropriate. In central Mexico, the typical race {G. v. variegatus) is reported by Nelson and Goldman to live on rocky hill- North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey PLATE 6 1938] REVISION OF THE GROUND SQUIRRELS 23 sides, along stone walls or irrigation ditches, and in cactus or mescal hedges, often ranging out into cultivated fields. Their burrows are dug usually under a large boulder or sometimes in thickets. Al- though typical ground squirrels, they climb trees readily in search of food, and occasionally make their homes in hollow trees as high as 15 or 20 feet from the ground (Bailey, 1905, p. 85). They often climb to the tops of juniper trees to gather the berries, and into mesquite trees to eat the green buds or the beans. The rock squirrels are knov/n to store food extensively for use in winter, and it seems probable that over the greater part of their range they remain more or less active throughout the year. Wliether they ever actually hibernate is not known. During the colder parts of the year they are seen out of their dens only on mild, sunny days. Their food supplies, consisting chiefly of acorns, walnuts, and the seeds of peaches, plums, and apricots, are stored in earth burrows, in cavities in cliffs or under boulders, and in hollow trees. The voice of the rock squirrel is described as "a loud, shrill whistle — a single note repeated at irregular intervals" (V. Bailey, ms.). Food habits. — The food of the rock squirrels comprises a long list of vegetable materials and includes also grasshoppers, crickets, cater- pillars, and other insects. Nuts, including acorns, walnuts {JuglaTis rupestris), and pine nuts {Pinus edulis) probably furnish a large part of the yearly food. Other seeds that have been found in the cheek pouches or stomachs of these squirrels are tliose of mesquite, cactus, saltbush {Atriplex), wild gourd, wild cherries, muskmelon, watermelon, fragrant sumac {Rhus aromatica)^ Nevada jointfir (Ephedra nevadensis),servicebevry {Amelanchier) , spurge (Euphor- bia), and marbleseed (Onosmodium oceidentale) , and berries of the wax currant (Ribes cereum). The rock squirrels are reported to feed on wild figs, cactus fruit, blossoms of the mescalbean (Sophora secundifora) , and the flowers and tender tips of the agave, A specimen of Say's rock squirrel (O. v. grammuims) taken in New Mexico had its pouches stuffed with the berries of the cherrystone juniper (Juniperus monosperma) ; one taken in Texas had filled its pouches with the berries of the alligator juniper (Juniperus pachy- phloea). In Colorado, according to W. L. Burnett (1918, p. 23), the food of rock squirrels of this subspecies "consists of seeds of various kinds, apples, cherries, apricots, chokecherries, blackberries, squash, and melons. They also eat garden peas, grains of all kinds, and feed to some extent on the seed pods of the Yucca and Indian breadroot (Psoralea) ." Economic status. — The rock squirrels, wherever they come in con- tact with agricultural operations, are considered a serious pest. They are known to carrj^ off whole ears of corn and to damage all kinds of grain. Fruit trees, including peaches, pears, plums, and apricots, are visited and the fruit carried off to be eaten or the seeds stored. CALIFORNIA GROUND SQUIRREL AND RELATED RACES General habits. — Grinnell and Dixon (1918, p. 606) describe the habitat of the California ground squirrel (Gitellus beecheyi beecheyi) (pi. 8) as follows: Its proforences as to local conditions are not closely limited, except that it avoids dense chaparral and thick woods. It frequents pasture lands, grain 24 NORTH AMERICAN FAUNA [No. 56 fields, orchards, sparsely tree-covered slopes, small mountain meadows, rock outcrops on the tops of ridges, and even granite talus slopes. It is always most abundant, however, in the open situations, and its decided preferences are such that it thickly populates much of the best farming and grazing lands in the State, to the great reduction of their producing value from the human standpoint. Although a true ground squirrel, this species is able to climb trees with ease and the animals are often seen in oaks or other nut-bearing trees and in fruit trees. Burrows and nests. — ^Writing of the animals' burrows, Grinnell and Dixon (1918, p. 606) say: In shallow adobe or clayey soil, underlain by broken rock, the burrows were found to be short, of small diameter, and not reaching to any considerable depth. Those in alluvial or sandy soil were found to be of large diameter, of greater extent, and to reach to much greater depths. The most conspicvious signs of activity on the part of ground squirrels in any locality are the large mounds of earth that have accumulated in the course of excavating the burrows. This earth is commonly thrown out in a fan- shaped pile directly in front of. and to the sides of the main entrance to the burrow. These mounds of earth are often 3 or 4 feet in diameter and from 6 to 10 inches above the general level. Seven burrows of this species were excavated by Grinnell and Dixon, who report that the shortest occupied burrow was 5 feet in length and the longest 138 feet, the average length being 35.2 feet. These burrows varied in depth from 18 to 66 inches below the surf ace> Three types of burrows are described by them (1918, p. 612) : The male squirrels were usually found in short, shallow, simple burrows at the outskirts of the "colony." ... It is believed that at least during the breeding season the male squirrels live altogether by themselves in their own individual burrows. The second type was illustrated by a single burrow, 22 feet in length and 30 inches deep, containing a female and four young with eyes still unopened. This burrow was much more complicated than those occupied by the males. The third type of burrow might well be called a "colonial burrow", as it is used by both sexes and also by the young after these leave the nest burrow and begin to forage for themselves. Colonial burrows are used largely as "safety zones." They afford convenient places for the squirrels to duck into when danger unexpectedly appears. These burrows are often from 100 to 200 feet in length and form a communicating system of underground runways connecting from six to twenty entrances or surface openings. . . . Each burrow occupied by a single squirrel was found to contain at least one well-made nest. In some cases there were two, one obviously older than the other. In the colonial burrow that was dug out, three nests were found, of which two were new. The nests were always placed well back in the burrows, where they would have maximum protection from digging enemies such as coyotes and badgers. The cavities in which the nests were placed were short globular chambers and were usually situated slightly above and to one side of the main run, so that the drainage was away from rather than into the nest. . . . All of the nests found were of similar composition and construction. Finely shredded dry grass blades and roots, and fine stems of foxtail and needlegrass, formed the bulk of the constituent material. The nests were spherical in shape and deeply cupped. The walls were from two to two and one-half inches thick (1918, p. 615). Breeding. — The principal breeding season in the lowlands extends from February to the middle of April; at higher altitudes it occurs later, even into June. The litters number from 4 to 11, averaging 7.5. North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey PLATE 7 ^SB.M-^ 1938] REVISION OF THE GROUND SQUIRRELS 25 In the lowlands thq majority are probably born the last of March, and by the last of April the first-born are beginning to appear above ground, playing about the mouths of the burrows (1918, p. 620). Hibernation. — In these ground squirrels hibernation is not univer- sal, and it is not yet known to what extent the animals become dor- mant. Over the greater part of their range some individuals may be seen abroad most of the year. There are specimens in the Biological Survey collection taken at Los Banos, Calif., on January 3 and 4 and at Modesto on December 13. Grinnell and Dixon (1918, pp. 631, 632) present a table showing that large numbers of the animals were taken in January in Contra Costa County, the great majority of which were young adults. In their opinion: "It is probable that the full old-adult population is not abroad aboveground until the last of February." These writers cite an/ instance of a squirrel observed closely for a number of years in Pasadena that did not estivate until its second year. Then and during each succeeding year of its life it estivated regularly, becoming very fat and retiring to its burrow during the last week in August. It emerged lean and hungry, with marked regularity, about the twenty-second of each following February. When removed from the burrow at intervals dur- ing this period, the squirrel was found to be in a torpid state, with respira- tion not perceptible. It seems probable, therefore, in view of this single instance, that a certain proportion of adults of this species living in the lowlands regularly hibernate. According to Grinnell and Storer (1924, p. 164)— Those individuals which live above the snow line in the mountains hibernate for considerable periods during the winter months. In Yosemite Valley, ground squirrels in 1920 were first seen out of their burrows about the middle of March, according to Mr. Forest S. Townsley. One exceptional individual was seen out by one of us, on the Big Oak Flat Road below Geutrys, on December 28, 1914. Storage of food. — These ground squirrels regularly carry off in their cheek pouches various seeds and heads of grain, as well as acorns and olives, and store them in their burrows. Writing of this habit, Grinnell and Dixon (1918, p. 628)- say: In Strawberry Canyon on the University campus, in April, the squirrels were harvesting foxtail and alflleria on sunny southern exposures where the plants had matured early. Later in the season, during late June and eai'ly July, these same squirrels with their families of half-grown young were found to have moved down the hillsides, some 150 yards, to the moister, shady ground near the creek bed where the foxtail was still green, and here they were busily gathering the foxtail heads just ripening on July 6. . . . In digging out a colonial burrow near Bakersfield, Kern County, on May 3, 1918, a storehouse was uncovered. This consisted of a cavity or pocket off the main run, which measured five and a half by eight inches in two diameters and was eighteen inches beneath the surface of the ground. The stored food consisted of a double handful of nearly dry heads of foxtail grass carefully packed in dry sand. A few alfileria seeds were also included with the foxtail (op. cit. p. 629). Merriam (1910, p. 5) writes of the storing habit as follows: In Modesto in May 1909, Piper found stores of alfileria seeds packed in cavi- ties and well mixed with dry sand. In December of the same year he ex- amined a number of stores of grain unearthed by a farmer while scraping and leveling his land. Each of these caches consisted of from a pint to a quart of oats stored in cavities and packed in dry sand. 26 NORTH AlVIERICAN FAUNA [No. 56 Hollister was told by farmers at Aptos that a burrow that had been opened in a wheatfield was found to contain 3 pecks of shelled wheat. Food habits. — The California ground squirrel feeds on a great variety of seeds, nuts, fruits, and green herbage. Merriam (1910, p. 4) states — Acorns are a favorite food and where obtainable are gathered and stored in large quantities. The same is true of nianroot (Echinocystis fahacea), the seeds of which are eagerly eaten, according to Piper, from the time they begin to form until fully ripe. At Modesto the squirrels were eating them as early as the middle of May and as late as the middle of December. Other favorite seeds are those of elderberry (Samiucus) , jimson vs^eed (Datura), wild nightshade (Solanum), turkey mullein (Eremocarpus) , tarweed (Madia), and numerous grasses. Of cultivated nuts, almonds and walnuts are preferred ; of other crops, apples, prunes, peaches, apricots, figs, olives, certain garden vege- tables, the seeds of cantaloupes, watermelons, and citron melons, and all the grains are eaten wherever they are to be had, and green alfalfa and clover are sometimes taken. In November — sometimes earlier, according to the date on which the early rains begin — tender green vegetation becomes abundant, and the ground squirrels turn their attention to it. At this season their chief food consists of green stuff, mainly young wild oats and filaree, the latter a small member of the geranium family widely distributed in California and valued as a forage plant. In several localities in March the cheek pouches of animals examined by Piper were filled with the yet green seeds of filaree. In June the pouches are often filled with alfalfa leaves and flowers. In southern Cali- fijrnia the squirrels are fond of the fruit of the prickly pear (Opuntia). Grinnell and Dixon (1918, p, 628) say that on wild land, alfileria, foxtail, and bur-clover are perhaps the three forage plants that are eaten to a greater extent than any others. The same authors (p. 626) mention a ground squirrel taken at Cisco in October that was carrying in its pouches 92 seeds of the green manzanita (Arctostaphylos patula) and another taken in Mari- posa County that had dug up and was carrying in its pouches 12 bulbs of a species of wild-hyacinth (Brodiaea hyacinthina) . Economic status. — It may be seen from statements in the life liistory of this species that the California ground squirrel is capable of great injury to agriculture. In California, where it is considered to be the most important of the rodent pests, large sums of money are expended in efforts to control its depredations. In addition to the damage inflicted on crops of grain, forage, fruits, and nuts, the ani- mals are reported to destroy young chickens. In recent years this species has been found to be a carrier of both bubonic plague and tularemia. Plague appeared in California in 1900 and shortly thereafter it was found to be present in these ground squirrels. Dr. W. H. Kellogg (1935, p. 856), writing of the plague in California, said : Infected squirrels [Citellus beeclieyi] were found in 1908, and plague has been enzootic among the squirrels of California ever since. At that time an acute and very severe epizootic ensued, the number of plague-infected squirrels picked up in that county [Contra Costa] being over 1,700 during the few years following 1908. This epizootic extended in the neighboring counties of the Bay area and it was accompanied by a human epidemic in San Francisco and Oak- land, the number of cases between May 1907 and June 30, 1908, when the last case of this second epidemic of human plague occurred, being 160 and the number of deaths 77. Eradicative measures were carried on jointly by the Public Health Service and the State Health Department from 1908 to 1912, covering North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey Plate < q: J CD D 0 Q 1938] REVISION OF THE GROUND SQUIRRELS 27 most of California and parts of adjacent States, and at the end of that campaign it was thought that danger of further spread of the plague had been removed. In the spring of 1934, however, fresh out- breaks of plague were discovered in Kern and Tulare Counties, and as a result of exterminative measures carried on in these counties from March to July, 5,973 squirrels were shot and 2,853 found dead, and of those sent to the laboratory, 118 were reported to be infected. The number of plague foci located was 41 over an area of approxi- mately 896 square miles. Tularemia was discovered in the California ground squirrel by Surgeon George W. McCoy in 1910 (1911, p. 53) while searching for league in this rodent. According to Francis (1937, p. 106), hovv- ever, human cases of tularemia have not as yet been traced to this animal. DOUGLAS'S GROUND SQUIRREL General habits. — The habits of Douglas's ground squirrel {Citellus heecheyi douglasii) (pi. 8) in California are described by Grmnell and Dixon (1918, p. 646) as follows: The local or habitat preference of this species is more exclusively for hilly country than in the case of the California ground squirrel. It is true that the Douglas exists out on the floor of the Sacramento Valley nearly to the lands annually flooded along the river ; but it occurs there interruptedly, in far sepa- rated "colonies", and never anywhere are the great numbers reached that char- acterize heecheyi in the San Joaquin Valley. The preferred haunts of douglasii are the openings or glades on hillsides, beneath scattered oaks or pines, or else the open tracts along stream courses, not, however, quite down to the water's edge. The edges of the smaller valleys between the coast ranges are well populated, but the open floors of these valleys are not often invaded very far or in any considerable numbers. Dense chaparral and thick woods are avoided altogether. . . . Steep banks seem to be cho.seu for burrowing into, whenever available. Many burrows open under rocks, bushes, and tree roots. On open, level ground, with no protective shelter at hand, the mouths of the burrows are marked by good-sized mounds, showing the presence of an extensive system below ground. As far as we know, no one has yet made a complete excavation of the burrow system of this species. Douglas's squirrel is reported to climb trees more frequently than the other members of the heecheyi group, and there are instances of individuals having been seen as high as 30 to 60 feet above the ground. The alarm call of this species, according to Vernon Bailey, is — a series of rasping squeaks with a rising inflection, somewhat like the cry of Ochotona. It is neither a whistle nor a chipper, but sounds like an attempted bark with something loose in the animal's throat. Merriam mentions an individual that uttered "a shrill whistle of sur- prising loudness and penetration, suggesting the alarm note of the marmots." Hibernation apparently is more prevalent in this subspecies than in any otlier races of heecheyi; at high altitudes the animals are re- ported to disappear completely for a period of 6 to 8 weeks in mid- winter. In the Sacramento Valley, at Chico and St. John, however, they were found out of their burrows on sunny days in winter and 6 specimens were taken there on January 4 and 6, 1906. The young are brought forth during May in the lowlands, prob- ably later in the mountains. Two specimens taken at Lower Lake, Calif., April 23, contained, respectively, five and six embryos; one 28 NORTH AMERICAN FAUNA [No. 56 taken at Slierwood, Calif., May 5, contained seven embryos ; one from Eel River, May 18, contained five; and one from Cliico, May 20, contained five, nearly ready for birth. Food habits. — The food of this ground squirrel consists largely of the seeds and fruits of a variety of wild plants, with the addition of cultivated grain and some insects (grasshoppers). The plant food recorded by the field collectors of the Biological Survey as found in the cheek pouches of these squirrels is as follows: Acorns, chin- quapins, nuts of the California buckeye {Aesculus calif ornica) and the California-laurel {Umhellularia calif ornica)^ maple seeds, berries of skunkbush {Rhus trilohata), camas bulbs, seeds of California bur- clover {Medicago hispida), alfileria, and bitterbrush {Purshia tri- dentata)^ wild oats, and wheat. Grinnell and Dixon (1918, p. 648) list the following items found in cheek pouches of this species; 29 seeds of a wild lupine {Lupinus micranthus) ; 12 seeds of milkthistle {Silyhum marianum) ; 219 grains of barley and one head of buck- horn plantain {Plantago lanceolata) ; 121 seeds of bur-clover {Medi- cago hispida) ; 181 seeds of California brome {Bromus carinatus) and a piece of an acorn; 29 seeds of Malta star-thistle {Gentaurea melitensis) and 30 seeds of bur-clover; 14 whole fruits and 103 sepa- rate seeds of the common manzanita {Arctostaphylos inanzanita) . Economic status. — Douglas's squirrel apparently is less prolific and never reaches the extreme abundance of the subspecies heecheyi and flsheri. Locally, however, the animals prove destructive to crops of wheat and barley and to the almond crop ; Grimiell and Dixon (1918, p. 648) state that the squirrels have been known to invade apricot orchards, where they climb the trees and take out the apricot pits, discarding the fruit pulp. RING-TAILED AND GOLDMAN'S GROUND SQUIRRELS General habits. — In their notes on Biological Survey field work, Nelson and Goldman write of the habits of the ring-tailed and Gold- man's ground squirrels {Citellus annulatus subspp.) (pi. 9) as observed in Colima, Mexico, as follows : On the flat country about Armeria they are excessively common and in this locality one could have shot 20 in a morning. As a rule they are not shy although many will rush into their burrows at first glimpse of an intruder. We found their burrows on hillsides, among the rocks ; and again in the sandy flats, along walls and hedges bordering cultivated fields; they are equally at home in the silent and gloomy shade of the densest groves of oil palms, with a burrow under a mass of fallen palm fronds or sheltered by the thorny growth of mesquite and acacia. Again their burrows are found under a cactus whose spreading branches give safe shelter on more open ground. The nuts of the oil palm, mesquite beans, cactus seeds and the fleshy fronds of the pear- leaved cactus, wild figs, moho nuts, and a variety of other seeds and fruits make up their varied bill of fare. In going silently along the trails leading through the dense palm groves and thickets of other trees, where the "tezmo" lives, they may be seen gliding silently from log to log or from one bunch of brush or similar shelter to another, now stopping a moment to dig for a seed or sitting up on their haunches to eat some morsel and then on again. They are often seen 10 or 12 feet up on the trunk of a small tree — sometimes out on the ends of branches after mesquite beans, cactus leaves, or other fruit — and when surprised they frequently run up a tree a few feet, take a hasty look at the intruder, then around the tree, down the other side and away in a direct line, so that before one knows it he may see his expected prey whisk into a brush pile or hole many yards away. Often they will crouch close to the ground and lie very still in the bushes so that they are only seen by accident, whUe others will North American Fauna No. 56, U. S. DepU of Agriculture, Biological Survey ;ip^ f logical Survey PUATE 9 I V 1 3 ' ' 4 *9 * Ji 4 v^^^ %JV 1938] REVISION OF THE GROUND SQUIRRELS 29 steal softly away to some sheltering hole and thence utter short, shrill, whis- tling or chirping notes at short intervals. This is the only note we have heard them give. When their curiosity is aroused they will draw near, stopping to stand up on their hind feet, sometimes stretching the body up so that the tail is used to help support the body as on a tripod. At the first alarm they scurry away into the first shelter. They carry their tails in a curve quite squirrel-like in character and their motions are more light and agile than those of most spermophiles. LESSER TROPICAL GROUND SQUIRREL General habits. — The habits of the lesser tropical ground squirrel {Citellus adocetus) are described in the field notes of Nelson and Goldman as follows: They live among rocks along canyon sides, about stone walls and corrals near ranches, and sometimes their burrows are located in open ground at the base of a tree or bush. They are seen running about at all hours of the day, but are most active from 9 to 11 in the morning. Near ranch houses they become quite tame and often approach to within a few feet of the doors after scraps of food thrown out by the people. In the fields and scattered woods where they occur they are rather shy and retreat to their holes at the first sight of a person or other cause of alarm. They were abundant about the ranch near La Huacana rMichoacan] and especiall.v numerous along the stone walls bordering the trail near the ranch of Agua Blanca and in the old lava beds extending away from the south base of the volcano of Jorullo. We left Agua Blanca early in the morning with the sun just becoming warm, and dozens of these little animals were seen scampering along the trail ahead of us, sometimes playfully pursuing one another or sitting up to look about. As we drew near they ran to the stone walls and either sat on the top or took refuge in the crevices and with heads projecting from the holes watched us pass. Now and then one scurried away to a hole under a stone or at the foot of a tree or bush. Their habits here w^ere remarkably like those of Citellus annulatus aloug the stone-walled roads near the city of Colima. The present species has a sharp chirping call note. At the ranch near La Huacana they were living mainly in holes under rocks or bushes, but some also in stone walls. Wherever they are located along roads they have become accustomed to people and are less shy than in more unfrequented places. ANTELOPE GROUND SQUIRRELS General habits. — The antelope ground squirrels (subgenus Am- mospermophilus) (pi. 10) live chiefly in Sonoran Zone deserts, occupying open country among bushes and clumps of cactus and showing a preference for more or less rocky situations. They dig shallow burrows under bushes or among rocks and apparently use also the burrows of other animals, especially those of the large kan- garoo rats {Dipodomys) . They apparently do not hibernate, but during severe weather may remain for long periods within their burrows. E. R. Sans says he has seen them out on top of a foot of snow. They are active, nervous, and very wary creatures, and when alarmed run rapidly to cover with their tails held straight up or curled over their backs. They are good climbers and are often seen sitting in a bush or clump of cactus, several feet alcove the ground. Their notes are described as "a shrill, rapid chipper." The youn^, numbering usually 6 to 9, or occasionally 12, are brought forth in March or April. Food habits. — The food of the antelope squirrels consists chiefly of the seeds or berries of a large variety of desert shrubs. The fleshy fruit and the seeds of various species of cactus are frequently eaten, as are also seeds of mesquite, huisache [Acacia farnesiana), 30 NORTH AMERICAN FAUNA [No. 56 yucca, palo verde {Cercidium fioriduin)^ ocotillo {Fouquieria splen- dens), sotol {Dasylirion texanum), saltbush (Atriplex), Kussian- thistle, skunkbush (Rhus ti^ilohata) , greasewooa {Sarcobatus)^ sun- flower, wild plum, and single leaf pinyon (Pinus monophylla) . Small numbers of insects have been found in tlie animals' pouches. A specimen taken at Kesting Springs, Calif., February 9, 1891, had 46 grains of barley in its cheek pouches. Economic status. — ^Living chiefly in desert regions, the antelope squirrels do not often come in contact with cultivated crops; but Bometimes in irrigated valleys they are attracted to grainfields and gardens and in such cases may cause damage by destroying ripening grain or planted seeds of melons or corn. MOHAVE GROUND SQUIRREL General habits. — Burt (1936, p. 221) has given an account of the habits of the Mohave ground squirrel {Oitellus mohavensis) based on a study made at Palmdale, Calif., in the spring of 1931. From this account, the following facts are selected. The animals live on the lower desert, preferring areas where the soil is sandy or of sand mixed with gravel, and where there is a sparse growth of sagebrush. Their burrows enter the ground at an angle of about 35° ; one examined was a simple tunnel 54 inches in length, 12 inches below the surface at its deepest point, with two entrance holes 2 to 2i/2 inches in diameter. Some of the burrows had been partially plugged with earth after the entrance of the animal. The squirrels rarely run rapidly for any distance, and when danger threatens they dodge into a hole or sometimes crouch low on their bellies and remain quiet. When running the tail is carried over the back, after the manner of Ammospermophllus, but is not twitched. If slightly startled the animals rise upon their hind feet — "picket- pin" fashion — with the front legs hanging limply. A squirrel observed for 50 minutes on April 12 fed in a patch of green vegetation, chiefly alfileria; occasionally it climbed into small bushes to a height of about a foot and ate some green buds. Its call "resembles a shrill whistle. It is a high pitched peep, with a slight rasping effect." A female taken March 29 contained six embryos ; one taken April 12 was suckling young. ROUND-TAILED GROUND SQUIRRELS General habits. — The round-tailed ground squirrels [Oitellus tere- tioaudus subspp.) are typical desert animals, living in the hottest parts of the Lower Sonoran Zone in southern California and Ari- zona. They occur in more or less isolated colonies in mellow, sandy soil. Grinnell and Dixon (1918, p. 669) say that these ground squirrels prefer areas where wind-drifted sand has been accumu- lated into mounds about the bases of mesquite, creosote, or saltbushes. They make use of the burrows of other rodents, particularly kan- garoo rats, but sometimes they dig burrows for themselves in the sandy flats or in the banks of a gulch or dike. These burrows may be 5 or 6 feet in length and reach a depth of 2 to 3 feet. Several examined by Vernon Bailey contained nests of grass at the lower end. North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey Plate 10 (\. ^ 1 1938] REVISION OF THE GROUND SQUIRRELS 31 Living in a mild climate, these squirrels apparently do not hiber- nate completely, but they are rarely seen on cold or cloudy days dur- ing the winter season and may remain in their burrows for somewhat extended periods. At Fort Lowell, Ariz., in midwinter, A. Brazier Howell noted them out only about once a week until January 24, after which they became abundant. Early in February the females ventured out infrequently and appeared ragged, but the males were in good pelage. Near Tucson, Ariz., the first were seen out of their burrows on January 27. A specimen was taken at Needles, Calif., December 12, and one at Agua Caliente on January 15. Although chiefly ground dwellers, these squirrels occasionally climb into bushes in search of food or to survey the surrounding country. Swarth (1929, p. 349) mentions seeing one 10 feet or more up in a mesquite tree. Their voice is described by Vernon Bailey as a fine shrill whistle, so thin and sharp that it sounds like the note of an insect. He says that there is no vibration or trill to it, as in the voice of the members of the spilosoma or the tridecemlineatus groups, but that it is often prolonged and evenly sustained. The young are brought forth in March and April and there may be a second litter later in the season. Two specimens taken in Death Valley, Calif., April 7, contained six and seven embryos, respectively. Three taken at Fort Mohave, Ariz., March 11 and 12, contained 10, 11, and 12, respectively. One taken at Ivanpah, Calif., June 2, con- tained eight. Food habits. — Stephens (1906, p. 70) says of this species: The food is seeds the greater part of the year; these are stored to some extent. In the spring, during the few weeks when green vegetation is obtain- able, leaves and buds are eaten voraciously. Grinnell and Dixon (1918, p. 671) state that stems of the "squaw- tea" or jointfir {Ephedra) and leaves of the mesquite form an im- portant element of the diet wherever and whenever obtainable. They state, also, on the authority of W. C. Jacobsen, that in the Imperial Valley these squirrels were known to invade alfalfa fields and to eat the alfalfa leaves, discarding the stems. Among the food elements recorded in the stomachs or cheek pouches of this species are cactus fruit, blossoms of ocotillo {Fou- quieria splendens), mesquite beans and leaves, seeds of plantain {Plantago) and of goosefoot {Chenopodium) ^ wheat, barley, and small insects. Living mainly in desert areas, these squirrels rarely come in con- tact with agricultural crops and they are therefore of little economic importance. MANTLED GROUND SQUIRRELS General habits. — The mantled ground squirrels (subgenus Callo- f>permophilus) (pi. 11) inhabit mountain slopes and foothills, living in the more open forested country among rocks and fallen timber. Their burrows are dug usually under rocks or stamps, and the ani- mals spend much time resting quietly on some rock or log in the sun- shine. They occasionally climb into bushes or trees to a height of 20 or 30 feet m search of food, but their ordinary habitat is on the ground. They are of rather sluggish movements and when running, elevate the tail at an angle of about 45°. Ordinarily they are silent. 32 NORTH AMERICAN FAUNA [No. 56 but Bailey says that on occasions tliey utter a clear, birdlike whistle, very shrill and piercing, entirely unlike the note of the chipmunks. When gathering food supplies, they often pack their capacious cheek pouches so full that their cheeks stand out as in a case of the mumps. In fall they store food in underground chambers. Hibernation. — These squirrels become very fat early in fall and by the middle of September most of them have retired underground for their winter's sleep; a few, however, may be found out of their burrows in October or November (Lake Tahoe, Calif., Oct. 6; Tula- rosa Mountains, N. Mex., Oct. 12 ; Mogollon Mountains, N. Mex., Oct. 28; Pikes Peak, Colo., Nov. 2 (Hatt, 1927, p. 19) ). In the Bitterroot Valley, Mont., the first one seen in spring was on March 28 (1910) and by April 10 they were observed in numbers. In milder climates they may come out of hibernation earlier than this. Females carry- ing four to six or rarely eight embryos are recorded during May, June, and July. Burrows and nests. — Hatt (1927, p. 8) describes a burrow examined in Douglas County, Colo., as follows : The diametei' of the burrow at the entrance was 3 inches. For the distance of a foot there was a 45° angle and then the course flattened out to a depth uniformly 8 inches under the surface, except at the opposite end and in one of the pockets. A few inches past the entrance the tunnel narrowed down to a uniform 2-inch bore. At one place in its course the roof was crossed by the root of an aspen. Farther on the tunnel passed directly under the base of a tree and beneath its roots. The first pocket leading from the main passage contained no debris of any sort, and at the time of the excavation could not have been in use unless it was a passing place or unlined nesting site. Six feet in from the entrance the passage forked, one lead passing directly to the nest, the other passing to it by a semicircular arc. A runway surrounded the nest on three sides, from which there were four passages leading in. This nest cavity was 4 inches deep, the nest not filling the space available, but occurring more as a mat in the bottom of the cup. A passage led away from the nest in the direction opposite from that of the other main passage. Six inches from the cavity this forked, one branch lead- ing from an empty chamber 5% inches in diameter, beyond which was a blind lead filled for a distance of about 12 inches with old nesting material, firmly packed. The other branch led by an angular path and a sharp grade to another entrance completely obscured by kinnikinnik and hidden by a mat of leaves. Food hatits. — The food of the mantled ground squirrels is chiefly of vegetable origin and comprises a large variety of the seeds and berries of wild plants, including acorns and seeds of yellow pine and Douglas fir, small wild beans, serviceberries (Amelanchier) , gooseberries (Grossularm irrigua), currants, thimbleberries, and the seeds of roses, lupine, puccoon {Lithosipermum) ., alfileria, clover, Polygonum, shepherds-purse (Ca'pseUa) ., milkvetch {Astragalus) ., false-indigo {Am.morpha calif ornica) ., willowweed (Epilohium), beardtongue {Penfsteinon), bitterbrush (Purshia tridentata) ., gilia, and greengentian (Frasera). One squirrel captured had 410 weed seeds in its pouches : another had taken 360 grains of barley, gatliered along a road. Mushrooms are frequently eaten, as also are grass- hoppers, beetles, caterpillars, ants, flies, and various other insects. Hatt (1927, p. 12) reports seeing one of these squirrels feeding on the fruits of stickleaf {Menfselia nnuXtif,ora) . Vernon Bailey ex- amined a specimen in Oregon that had filled its cheek pouches to their limit with ripe seeds of the Nuttall violet {Viola nuttallil). North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey PLATE 11 1938] REVISION OF THE GROUND SQUIRRELS 33 Economic status. — ^Living as they do chiefly in mountainous and unsettled areas, these squirrels rarely come in contact with civiliza- tion. In certain valleys, however, they at times forage in grain- fields and destroy considerable quantities of wheat, oats, or barley. Around hunters' or miners' camps they are often attracted by stores of food and unless means are taken to keep them out they will per- sistently carry off any food materials that appeal to their taste. in4970 — 38- CLASSIFICATION OF THE NORTH AMERICAN SCIURIDAE In connection with the present revision of the North American ground squirrels, it seemed desirable to make a critical study of all the North American members of the family Sciuridae, in an effort to devise a classification in which the generic and subgeneric groups can be based on the most constant and deep-seated skeletal charac- ters. This has proved to be a task of considerable difficulty, for although the various groups commonly recognized are easily sep- arable by external characters, critical study of their cranial and dental characters (pi. 12) reveals in many cases close relationship among a number of groups, shown by extensive gradation from one to another in supposedly diagnostic characters.^ The lack of agreement among zoologists as to what characters should be used to characterize a genus results in great diversity of treatment by systematic workers and consequent confusion of the laymen, who are naturally less interested in questions of relationship than in stability of the names they are called upon to use. A genus is sometimes a natural group, but is often merely a concept in the mind of the systematist by which certain related species are associated under a single generic name. The limits of a particular genus, therefore, may be subject to change at the will of any reviser, as his viewpoint with reference to generic characters changes, or as new facts or new species come to his attention. This situation is well illustrated by the evolution of the generic concept in the mind of one of our most distinguished American zoologists, the late J. A. Allen. In his monograph of the Sciuridae, published in 1877, he recognized a single genus — Sciurus — for all the tree squirrels of North America and South America. The five outstanding groups of North America were treated as species (some with several varieties) and nine additional species were recognized from Middle America and South America. In his last paper on the squirrels, published 38 years later (1915), working, of course, with a vastly increased quantity of material, he recognized eight genera from North America and nine additional genera from South America. Each of the five North American species recognized in 1877 was in 1915 given full generic rank — Tamiasciurus for the red squirrels; NeosGiwrus for the eastern gray squirrel; Otosciurus for Abert's squirrel of the Southwest ; H esperosciurus for the western gray squirrel ; and Para- seiurus for the fox squirrels. The same tendency to give generic rank to practically every recog- nizable group is more or less prevalent today among workers in other branches of zoology. Such a course results in our so-called genera becoming little more than specific groups. The purpose of ' In this study the writer has had the advice and assistance of Gerrit S. Miller, Jr., curator of mammals, U. S. National Museum, who generously turned over a partially com- pleted key to the genera of ground squirrels and related groups and also checked with the author the cranial characters of the various groups. 34 North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey PLATE 12 UPPER AND LOWER MOLARIFORM TOOTH ROWS OF CYNOMYS LUDOVICI ANUS. (Kiilarged about 0 diameters.) pa = paracone. TOC = inetac()ne. pr = i)rotoc()iie. parf = paraconi(i. fn/ = ent()coni). EXTEENAL CHAEACTEES Form as in most of the small ground squirrels; legs rather short, tail about half the length of the body, distichous, well-haired; ears short, broad and rounded; cheek pouches large; mammae, 10. The color pattern consists of a uniform background, with a single lon- gitudinal white stripe on each side. ilBACULAE CHAEACTEBS The baculum resembles that of the subgenus Citellus; the prox- imal end of the bone is thickened and laterally expanded ; the shaft is straight and slender ; ih& distal end is bent at right angles to the 1938] REVISION OF THE GROUND SQUIRRELS 45 shaft, and expanded into the shape of a shallow scoop, the edges of which are crenulate. Two specimens measured, respectively, 1.5 nmi and 2.2 mm in length (pi. 13, K and Z). Subgenus XEROSPERMOPHILUS Xerospermophilus Merriam, Biol. Soc. Wash. Proc. 7:27, April 13, 1892 (type, Spermophilus mohavensis Merriam). CEANIAL CHARACTERS Skull short and broad, similar in general shape to that of Citellus townsendii inollis but relatively broader in the interorbital region; postorbital processes shorter, broad at base, rapidly tapering to a point ; rostrum short and broad, tapering gradually ; brain case broad and slightly flattened; zygomata stout and moderately expanded; upper incisors moderately stout and slightly recurved ; molars brachy- dont (much as in Otospermophilus) ; ni^ and ni- slightly broader than long, the transverse ridges rather widely spaced ; anterior upper pre- molar small, less than one-fourth the size of ■pm'^\ audital bullae moderately inflated. Compared with AmmospermopJdlus this subgenus differs in hav- ing a shorter brain case ; heavier zygomata ; interorbital region nar- rower; antorbital foramen broader and more orbicular; anterior up- per premolar relatively larger ; postorbital processes stouter ; audital bullae smaller (pi. 14, Z>; pi. 17, D; pi. 20, 5). EXTERNAL CHARACTEJES Body stocky; feet stout; claws long, sharp, curved; soles densely haired; palms naked; thumb rudimentary^ bearing a broad nail; teats, 10; ears very low — a mere rim — tail 40-60 percent of the body length, somewhat cylindrical, well haired, but appearing terete when worn; pelage soft and silky when fresh, harsh when worn; coloration plain. BACULAE CHARACTERS The baculum of Citellus tereticaudus is similar to that of C. grammurus, but shorter, measuring 3.5 rnm in length; the shaft is much enlarged at the base and slightly curved upward; the tip broadens out to form a nearly circular "spoon" with pronounced crenulations on the margin; the tip of the shaft projects well be- yond the border of the disk on the under side (pi. 13, R). Subgenus CALLOSPEKMOPHILUS Callospermophtlus Merriam, Biol. Soc. Wash. Proc. 11: 189, July 1, 1897 (type, ScAurus lateralis Say). CRANIAL CHARACTERS Skull very similar in general shape and in proportions to that of Otospermophilus^ but upper incisors relatively slenderer and less chiseled off on inner face ; molarif orm teeth not appreciably different. Compared with Notocitellus : Skull relatively narrower interorbitally, the supraorbital foramen opening into the orbit; rostrum relatively narrower; upper incisors decidedly slenderer, zygomata more widely 46 NORTH AMERICAN FAUNA [No. 56 spread posteriorly; incisive foramina relatively larger (pi. 14, A] pi. 17, A; pi. 20, G). EXTEENAL CHARACTERS Body rather stout ; legs short ; tail usually more than half as long as the head and body (about one-third as long in Gitelhis madren- sis), distichous, well haired, ears large, rounded on superior margin (height from notch, 13 to 18.5 mm) ; claws slender, sharp, recurved; thumb rudimentary, bearing a short, broad nail ; cheek pouches large ; mammae 8 or 10. The color pattern consists of a longitudinal white stripe on each side of the back, bordered on one or both sides with a black stripe. BAOtTLAE CHABACTERS The baculum is a tiny bone, 2 mm in length, irregularly spatulate in shape. It has been dissected out in only one instance, and may not always be present (pi. 13,/). CHIPMUNKS The chipmunks (genera Tamias and Eutamias) are more nearly related to the ground squirrels than to the tree squirrels. The essen- tial characters distinguishing these two genera from Citellus (includ- ing all the subgenera) are as follows: Absence of an antorbital canal, the antorbital foramen being a relatively large opening in the zygomatic process of the maxillary ; the anterior border of the zygo- matic notch in the maxillary is opposite pmJ^ instead of m} as in all the ground squirrels; the transverse ridges on m} and mr are not parallel, the posterior loph being slightly divergent externally. Genus TAMIAS: Eastern Chipmunks Tamias Illiger, Prodromus Systematis Mammalium et Avium, p. 83, 1811 (type, Sciurus striatus Linnaeus). In general contour the skull of Tamias most nearly resembles that of Citellus {Notocifellus) annulatus. It differs from it and from all the ground squirrels in the absence of pm^ ; in the shape and position of the antorbital foramen; and in the attachment of the anterior root of the zygomata. The posterior border of the zygomatic plate of the maxillary is opposite the extreme posterior part of pm^ or sometimes the anterior edge of m?-. The superior outline of the skull is flat, and the brain case is shal- low; the upper incisors are short, moderately stout, and slightly recurved. The molars are low crowned, the cusps wide spaced, with slightly developed subsidiary cusplets between the primary cusps (pi. 15, 5; pi. 18, B; pi. 21, E). The color pattern consists of five blackish and two whitish longi- tudinal stripes on the dorsal area ; a median black stripe is bordered on each side with a broad band of gray or tawny about twice the width of the median stripe ; on either side of these dorsal bands are a pair of shorter blackish stripes with a whitish stripe between them. The baculumj of Tamias striatus is about 4.5 mm m length, nearly straight, but upturned at the tip and slightly expanded into the shape of a narrow spoon or scoop, with a slight median ridge on the under surface (pi. 13, A and B). 1938] REVISION OF THE GROUND SQUIRRELS 47 Genus EUTAMIAS: Western Chipmunks Eutamias Trouessart, Bull. Soc. d'Etudes Sci. d' Angers 10 (1) : 86, 1880 (type, Sciurus striatus asiaticus Gmelin). The western chipmunks are closely related to the eastern chip- munks {Tamias). The genus occurs also in eastern Asia, and the American species show some distinctive group characters, considered of subgeneric value. Compared with Tamias^ the skull of Eutamias has the rostrum shorter and more abruptly constricted at the base; the brain case is smoothly rounded, slightly flattened or moderately inflated ; the pal- ate is relatively shorter, terminating on the plane of last molars or but little posterior to it ; the notch in the zygomatic plate of the max- illary projects slightly more forward, usually being opposite the middle or posterior part of /?m'^; the audital bullae are relatively large; the upper incisors show numerous longitudinal striations, ' which in some species are well-defined grooves ; the molarif orm teeth are much as in Tamias^ but the anterior premolar {jpm^') is always present as a small peglike tooth. The color pattern is distinctive, consisting of five blackish and four whitish longitudinal stripes, all of approximately equal width (pi. 15, C\ pi. 18, G\ pi. 21, H). Subgenus EUTAMIAS The type of Eutamias is E. asiaticus of eastern Asia. The cranial characters distinguishing this subgenus from the American sub- genus Neotamias are as follows: Interorbital constriction slight (as in Tamias) ; postorbital processes broad at base, tapering to a point (much as in Tamias) ; antorbital foramen large, suborbicular (as in Tamias) ; lambdoidal crest moderately developed; upper molariform tooth rows slightly convergent posteriorly (as in Tamias) ; palate short, ending about on plane of last molars. In several of its char- acters this subgenus resembles Tamias more than it does the Ameri- can Neotamias. The baculum of E. asiaticus (one specimen) differs from that of the American species of Neotamias in being much more slender. It is 5 mm in length and tapers gradually from base to tip; the distal portion is upturned in an even curve and slightly flattened, but with- out ridges (pi. 13, C). Sabgenns NEOTAMIAS Neotamias Howell, North Amer. Fauna 52: 26, 1929 (type, Tamias asiaticus merriami Allen). The American members of the genus Eutamias present a number of characters distinguishing them from the typical members of the genus, which are confined to Asia. The postorbital processes are nar- rower at the base and much slenderer throughout; the interorbital constriction is more pronounced; the lambdoidal crest less strongly developed; the antorbital foramen smaller and narrowly oval rather than orbicular ; the palate ends slightly posterior to the plane of the last molars; the upper tooth rows are more nearly parallel. The ears are relatively longer and more pointed. The baculum in the members of this subgenus differs from that of both Tamias and typical Eutamias; specimens examined of six 4g NORTH AMERICAN FAUNA [No. 56 species show essential similarity in form but some variation in size. In a specimen of E. quadrivittatus f rater (pi. 13, E)^ the baculum resembles a human leg in general shape; it is 3.8 mm in length, thickest at the proximal end, and tapers gradually to the tip with a sharp bend in the middle of the shaft; the distal end is bent upward at almost a right angle, expanded and flattened in the shape of a human foot, with a prominent narrow ridge in the center of the "instep." In a specimen of E. cinereicoUis (pi. 13, F) the bac- ulum is 4.7 mm long and the shaft is stouter throughout. Bacula of E. toiunsendii sonomae (pi. 13, D) and E. dorsalis are about 4.5 mm in length and slenderer than in the other species examined. Genus SCIURUS: Tree Squirrels Sciurus Linnaeus, Systema Naturae (10) 1: 63, 1758 (type, Sclurus vulgaris Linnaeus). The North American tree squirrels are all remarkably alike in cranial characters, and not widely different from the typical spe- cies— /Sciurus vulgaris of Europe. South America has produced a number of aberrant groups that have been given the rank of genera (Allen, 1915, p. 147). These have not been studied by the writer. As already pointed out, the tree squirrels are distinguished from the ground squirrels and chipmunks by the great breadth of the interorbital region and the great depth of the brain case; the zygo- mata are nearly parallel to the axis of the skull and nearly vertical (not twisted as in Citellus), with an angular process on the upper surface of the jugal; the antorbital canal is a narrow vertical slit; the upper incisors are compressed laterallj^ and are relatively deep (much like those of Otospermophilus) . The molars are always low crowned and simple. The anterior upper premolar (pm^) is absent in some groups, present in others, but always very small. Subgenus SCIURUS The typical subgenus is not represented in America. The skull of the type species — Sciurus vulgaris of Europe — ^is relatively short and broad; the brain case strongly deflected at pos- terior end; a shallow depression in the anterior frontals with a swelling on posterior frontals ; zygomata nearly parallel, moderately expanded ; postorbital processes broad at base, tapering abruptly to a Ipng, slender point, depressed and directed backwards; antorbital foramen triangular, broadest at base; notch in maxillary plate of zygoma opposite pm^; prn? present, but very small and not rising to the level of pm^ ; pmJ^ subquadrate, narrowest on the inner side (pi. 16, F; pi. 19, F; pi. 22, D). The baculum of S. vulgaris^ according to Thomas (1915, p. 384), is essentially like that of S. carolinensis. Subgenus NEOSCIURUS Neosciurus Trouessart, Le Naturaliste 2 (37): 292, October 1880; Catalogus Mammalium, Rodentia, p. 76, 1880 (part) (type, Sciurus carolinensis Gmelin) . EcMnosciurus Trouessart, Idem (type, Sciurus hypopyrrhus Wagler = S. aure- ogaster hypopyrrhus). 1938] REVISION OF THE GROUND SQUIRRELS 49 Baiosciurus Nelson, Wash. Acad. Sci. Proc. 1: 31, May 9, 1899 (type, Scmrus deppei Peters). The skull of Sciurus caroUnensis — the type of the subgenus Neo- sciurus — does not differ widely in general shape from that of S. vulgaris but is relatively longer, with the brain case shallower and more elongated (less globular) and the rostrum longer and rela- tively narrower; the postorbital processes are shorter and stouter; the notch in the zygomatic plate of the maxillary is opposite m^ (instead of pm*) ; pm^ is present but not strongly developed; pm* is triangular rather than quadrate in outline, owing to the greater production of the parastyle QdI. 15, E; pi. 18, H; pi. 21, F) . In S. deppei (type of Baiosciurus Nelson), prn^ averages slightly more quadrate than the same tooth in Neosciurus^ but examination of a large series of deppei and cai'olinensis shows that the character is too slight and inconstant to serve as a basis for subgeneric distinction. Sciurus aii/reogaster hypopyrrhus and the large group of Mexican forms associated with it by Nelson in the subgenus Echino sciurus differ in general from 8. carolinensis in having a shorter and rela- tively broader rostrum and a more or less prominent depression in the frontals; these differences, however, are considered too slight to warrant recognition of the group. The baculum of Sciurus carolinensis is apparently closely similar to that of Sciurus vidgaris. It is 10.5 mm in length, the shaft stout, but tapering distally, curved upward near the tip, and flattened into the shape of a shallow scoop with the edges rolled up; on the lower side of the scoop is a small, blunt process (pi. 13, S). The baculum of S. deppei and that of S. adolphei dorsalis (pi. 13, T) agree essen- tially with that of S. carolinensis. The following species are included in Neosciurus: S. carolinensis, S. deppei, S. aureogasier, S. poliopus, S. yucatanensis, S. colliaei, S. truei, S. sinaloensis, S. nelsoni, S. socialis, S. griseo/lavus, S. goldmani, S. managuensis, S. boothiae, S. adolphei, S. thomasi, and S. variegatoides. Subgenus HESPEROSCIURUS Hesperosciurus Nelson, Wash. Acad. Sci. Proc. 1: 27, May 9, 1899 (type, Sciurus griseus Ord). The skull of Sciurus griseus resembles that of S. carolinensis very closely, except that it is larger ; pm* averages slightly more quadrate (less triangular), but examination of a large series of both species shows the character to be inconstant. The jugal is relatively lighter (shallower) and viewed from beneath shows less twisting from the vertical plane (pi. 15, G; pi. 18, G; pi. 21, A). The baculum is widely different from that of Neosciurus, re- sembling more closely that of S. aberti. The bone measuring 16.5 mm in length, is moderately curved and ends in a blade about 6.8 mm in length, with a curved and slightly twisted edge; the tip of the blade is a blunt point, but at its posterior end it forms a short, sharp hook (pi. 13, V). This subgenus comprises but one species S. griseics, of the Pacific coast region of the United States. 154970—38 4 50 NORTH AMERICAN FAUNA [No. 56 Subgenus OTOSCIURUS Otosciurus Nelson, Wash. Acad. Sci. Proc. 1: 28, May 9, 1899 (type, Sciurus aberti Woodhouse). In general shape the skull of Sciurus aberti closely resembles that of S. vulgaris; pm^ is relatively larger and more strongly developed, the crown being subject to wear with the rest of the molar series; the notch in the zygomatic plate of the maxillary is opposite the middle portion of m}. Compared with Neosciurus, this subgenus differs in having the brain case and interorbital region relatively broader; postorbital breadth less than the interorbital breadth; postorbital processes larger and longer; postorbital notch deeper; pm? more strongly de- veloped (pi. 16, E; pi. 19, E; pi. 22, ^) . The baculum is widely different from that of typical Sciurus and of S. carolinensis, and bears closer resemblance to that of S. griseus. It is a nearly straight bone, 16.1 nun in length, the distal portion flat- tened laterally into the shape of a blade with a curved edge ; on the lower side of the blade is a small tubercle (pi. 13, W). The species included in Otosciurus are: S. aberti^ S. kaihahensis, S. concolor, and S. durangi. Subgenus PARASCIURUS Parasciurus Trouessart, Le Naturaliste 2 (37) : 292, October 1880 (type, Sciurus niger Linnaeus). Araeosciurus Nelson, Wash. Acad. Sci. Proc. 1 : 29, May 9, 1899. The fox squirrels differ from the other North American squirrels (except Guerlinguetus) in the entire absence of pm?. Compared with Neosciurus the skull is of very similar shape, the brain case somewhat shallower and more flattened; the frontals are slightly elevated on the posterior half ; there is a distinct interorbital notch ; the notch in the maxillary plate is opposite the middle or hinder part of m^; the molariform teeth are very similar to those of Neosciurus (pi. 16, (7/ pi. 19, ^/ pi. 22, .g). The baculum is likewise closely similar in shape to that of Sciurus carolinensis (pi. 13, U). The subgenus comprises the following species: S. niger, S. ari- sonensis, S. apache, S. alleni, S. nayaritensis, and S. oculatus. Subgenus GUERLINGUETUS Ouerlinguetus Gray, London Med. Repos. 15: 304, 1821 (type, Sciurus guer- Unguetus Gray = S. aestuans Linnaeus). Mesosciurus Allen, Amer. Mus. Nat. Hist. Bull. 34 : 212, 1915.* The skull of Sciurus aestuans ^ is similar in shape and size to that of Tamiasciurus hudsonicus but has a deeper and more highly arched cranium; the rostrum is short and strongly "pinched in"; the zygomata are nearly parallel to the axis of the skull ; the postorbital processes are short and slender; the hinder portion of the frontals is swollen; the notch in the maxillary plate is opposite the hinder part of pm^ or the division between this tooth and m^; there is but * Allen proposed Mesosciurus as a genus mainly on the possession of eight mammae instead of six, as in Ouerlinguetus ; he states that there is "no very marked difference" in cranial or dental characters between these two groups. ^ Comparisons were made with a series of skulls from British Guiana, borrowed from the American Museum of Natural History (nos. 34874, 42344, 48137, 48392). 1938] REVISION OF THE GROUND SQUIRRELS 51 one upper premolar (pm^), which is subcircular or quadrate in shape, differing thus from Parasciurus and Tamiasciuncs, in which this tooth is subtriangular. The skull differs from that of Parasciu- rus also in having a shorter rostrum, more swollen brain case, and m the position of the notch in the maxillary plate of the zygoma (pi, 16, 5/ ph 19, 5/ pi. 22, F.) The subgenus GuerUnguetus is represented in North America by Sciurus richmondi^ S. hoffmanni^ and ^S". gerrardi. Genus TAMIASCIURUS : Red Squirrels Tatniasciurus Trouessart, Le Naturaliste 2 (37) : 292, October 1880 (type, Sciurus hiidsonicus Ersleben.) The red squirrels, or chickarees, differ from typical Sciurus in the vestigial character of the anterior upper premolar, which is often absent and when present is minute and never functional, being cov- ered by the crown of pm'^. The superior outline of the skull is much flatter, the brain case shallower and not strongly deflected posteri- orly; the zygomata are less expanded, being parallel to the axis of the skull ; the postorbital processes are much shorter. Compared with S. {Neosciunis) caroUnensis, T amiasciurns differs in the (usual) absence of pm^ and in having the notch in the zygo- matic plate of the maxillary opposite J9m* (instead of m})\ the rostrum is relatively shorter and broader, and tlie zygomata less expanded (pi. 16, D; pi. 19, D; pi. 22, E). Although the red squirrels exhibit no very marked cranial differ- ences from the other tree squirrels, the reproductive tract of the males is strikingly different from that of their relatives in the genus Sciurus. They have no baculum, and the penis is long and slender, tapering to a point. The anatomy of T amiasciurus hud- sonicus, in comparison with that of certain other sciurids, has been reported on by Mossman et al. (Mossman, Lawlah, and Bradley, 1932, p. 119) and their findings are summarized as follows: This species differs much more fundamentally from the sciurid type, such as 8. carolinensis, than any other studied. The striking differences in the male are: minute Cowper's glands opening into the urethra in the bulb, no penile duct, no bulbar gland, a true urethral diverticulum in the bulb, a long filiform penis, and no os penis. The seminal vesicles are excessively large. Anal glands are present. The female also differs from other female Sciuridae examined in having an unusually long, coiled vagina during oestrus. Genus MICROSCIURUS: Pygmy Squirrels Microsciurus Allen, Amer. Mus. Nat. Hist. Bull. 7: 332, Nov. 8, 1895 (type Sciurus alfari Allen). The genus Microsciurus comprises the smallest of the North Amer- ican squirrels. The skull is highly arched, with a pronoiniced swell- ing on the frontals at the plane of the postorbital processes; brain case is strongly deflected at posterior end; rostrum is short and broad ; upper incisors project forward to or beyond the plane of the tip of nasals; jugal is relatively wide, inferior margin abruptlv depressed anteriorly where it joins the maxilla; pm^ is well devel- oped (pi. 15, />; pi, 18, Z>; pi. 21, B). Included in this genus are the species M. alfari, M. hoqi/rfensis^ M. isf.hmius, and M. septentrionalis in Central America, and others in South America, 52 NORTH AMERICAN FAUNA [No. 56 Genus SYNTHEOSCIURUS : Pygmy Squirrels Byntheosciurus Bangs, Mus. Comp. Zool. Bull. 39: 25, April 1902 (type, Syn- theosciurus brochus Bangs). The skull of Syntheosciurus is similar to that of Microsdurus but Avith cranium more highly arched; frontals swollen; upper incisors projected forward, and having a broad, shallow groove; molariform teeth relatively large, pm^ present, reaching the crown of ^m*; au- dital bullae small ; postorbital processes slender. The fur is woolly ; ears short, broad, and densely haired ; whiskers rather short ; tail round and bushy. The genus is known only from the type species, occurring in Chiriqui, Panama (pi. 16, A ; pi. 19, A ; pi. 22, G) . Genus GLAUCOMYS: Flying Squirrels Glaticomys Thomas, Ann. and Mag. Nat. Hist. (8) 1: 5, January 1908 (type, Mus volans Linnaeus) . The genus Glaucomys, which comprises the American flying squirrels, differs widely in cranial characters from all the other groups of the Sciuridae. The skull resembles that of Sciurus in the great depth of the brain case and the shape of the zygomata, which are vertical (not twisted as in the ground squirrels) ; it differs from Sciurus in the extreme constriction of the interorbital and postorbital regions and the presence of a deep interorbital notch ; the postorbital processes are slender and project about in the middle of the temporal fossa; the incisors are rather slender, and not recurved as in most of the tree squirrels. The skull agrees with that of the chipmunks (Eutamias) in the po- sition of the notch in the maxillary plate of the zygoma, which is opposite ^7?i*, but differs from them and agrees with the ground squirrels m the possession of an antorbital canal. The cusps on the outer side of the upper tooth row are higher than in Sciurus or Eutamias and are without subsidiary cusplets; pni^ is present and is relatively larger than in Eutmnias; ptn^ is subquadrate, nearly as large as m^^ with the parastyle ridge rising to form a cusp; the lower molars resemble those of Eutamias in having small cusplets between the primary cusps (pi. 15, A ; pi. 18, A ; pi. 21, C) . The baculum of Glaucomys volans is 12.5 mm in length and rela- tively much slenderer than in Sciurus \ the shaft is twisted at the proximal end, and the distal end is bifid; the distal half is com- pressed on one side into a thin blade reaching to the tip (pi. 13, X). REVISION OF THE GENUS CITELLUS [For generic characters see p. 39] Citellus Oken, Lehrbuch der Zoologie (pt. 3) 2:842, 1816, (type, Mus citellus Linnaeus). Anisonyx Rafinesque, Amer. Monthly Mag. 2 (1) : 45, 1817 (type, Anisonyx irachiura Rafinesque (^Arctomys coliiniManus Ord)). Spermophilus F. Cuvier, Dents des Mamm., p. 255, 1825, (type, "Mus citillus Linn."). Spermophila Richardson, Parry's Second "Voyage, App., p. 313, 1825. Spermophillus Cuvier, Diet Sci. Nat. 59 : 473. 1829. Spermatophihis Wagler, Nat. Syst. Amphibien, p. 22, 1830. Spermophilis Richardson, Zool. Voyage H. M. S. "Blossom" ; Mamm., p. 12, 1839. ■Citillus Lichtenstein, Darst. neuer oder wenig bekannt. Sauget., pi 31, fig. 2 (not paged), 1830. Colohotis Brandt, Bull. Class. Phys.-Math. Acad. Imp. Sci. St. Petersbourg, 2 (23 and 24) : 366, 1844 (type, Spennophilus fulvus Lichtenstein). Otocolotus Brandt, op. cit., p. 382 { = Colodotis). Otospermophilus Brandt, op. cit., p. 379 (type, Sciurus grammurus Say). Colobates Milne-Edwards, Recherches Hist. Nat. Mamm. 1 : 157, 1868-74. Ictidomys Allen, Monog. North Amer. Rodentia, p. 821, 1877 (type, Sciurus tridecenilineatus Mitchill) . XerospermopMlus Merriam, Biol. Soc. Wash. Proc. 7: 27, 1892 (type, Spermo- philus mohavensis Merriam). Ammospermophilus Merriam, Biol. Soc. Wash. Proc. 7: 27, 1892 (type, Spermo- philus leucurus Merriam). Callospermophilus Merriam, Biol. Soc. Wash. Proc. 11: 189, 1897 (type, Sciurus lateralis Say). Ictidomoides Mearns, U. S. Natl. Mus. Bull. 56: 328, 1907 (type, Sciurus mexi- canus Erxleben). Urocitellus Obolenskij, Comp. Rend. Acad. Sci. URSS., p. 188, 1927 (type, Spermophilus eversmanni Lichtenstein), HISTORY AND NOMENCLATURE The ground squirrel of central Europe — the ziesel — was mentioned in literature as early as 1551, by Konrad Gesner (p. 835), his account being the principal basis of the Linnaean name 3Ius citelh(s, the type of the genus Citellus. GENERIC AND SUBGENERIC NAMES The ground squirrels were referred by most of the earl}^ naturalists to the genus Arctomys { = Marmota)\ the name Spermophilus was proposed for the group by Cuvier in 1825, but it did not come into general use until about 5 years later. The earlier name Citellus. of Oken (1816), was overlooked until revived by Allen in 1902 (p. 373) ; &ince then it has been in current use. Rafinesque (1817, p. 45) intro- duced the name Anisonyx^ but it was not used by later authors until revived for a short time by Merriam (1895a, p. 18) , and later the same year was found to be preoccupied (Merriam, 1895b, p. 107), The rock squirrels were separated by Brandt (1844, p. 379) as a subgenus — Otospermophilus — and they have been regarded since 1907 as a genus by Mearns and certain other writers. 53 54 NORTH AMERICAN FAUNA [No. 56 In the same paper, Brandt proposed the subgenus Colobotis to inckide all the Old World species known to him and also richard- sonii, ^'■hoodW^ { = tridecemlineatus) , and franhlinii of North Amer- ica. The type is Spermo'philus fulvus Lichtenstein, of southern Kus- sia. The name Golohotis has been used in a subgeneric sensa by several modern authors without any definite idea of its correct ap- plication, due to the lack of material representing the type species. Eecently, through the kindness of L. R. Dice, opportunity has been afforded to examine a single skull of Citellus fulvus (pis. 14, 17, 20) from Turkestan (no. 57827, Univ. Mich. Mus. ZooL), and this proves to agree in essential characters with Citellus parryii ablusus, and so far as can be determined from a single specimen it does not differ in any character of generic value from O. citellus, the type of the genus. The only character of importance distingushing the skull of Citel- lus fulvus from that of C. citellus (pis. 14, 17, 20) appears to be the presence on the former of a well-defined metaloph on m^ ; this loph is absent on the series of 12 adult skulls of C. citellus from Hungary, but is faintly developed on a single young individual from the same region. Unfortunately, no young skulls of C. fulvus are available, and it is quite possible that the metaloph of m^ may vary in the ex- tent of its development, as it does in numerous North American species. Of the North American species, those in which the metaloph on m^ is most strongly developed are C. pa7'ryii, C. osgoodi, G. columhi- anus, G. richardsonii, C. armatus, and G. ivashingtoni. In G. town- sendii molUs and G. idahoensis, this loph is absent or very slightly developed, while in C. heldingi it is sometimes present, sometimes absent. In consideration of the great variability of tliis character in the American species, and in the absence of any definite group charac- ters, it is considered inadvisable to recognize Colobotis as a subgenus. Allen (1877, p. 821) established the subgenus Ictidomys, but with- out naming a type; Merriam (Allen, 1895a, p. 418) fixed the type as Citellus tridecemlineatus. Merriam (1892, p. 27) already had es- tablished the subgenus Xerospermophilus, with Spermophilus mo- havensis as type, and the subgenus Ammos'permophilus for the antelope ground squirrels, using as type, SpermopMlus leucurus. The latter group since 1905 has been accorded generic rank by most au- thors. In the present study it is again reduced to subgeneric rank, as is also Callospennophilus, proposed by Merriam in 1897 (p. 189) as a subgenus to include the mantled ground squirrels, and since regarded as a genus by many authors. Mearns (1907, p. 328) proposed the name Ictidomoides as a sub- genus for the species Citellus mexicanus, but this is now considered the same as Ictidomys. Obolenskij (1927, p- 188) has proposed Urocitellus as a subgenus, with C. eversinanni as the type, but this species shows no cranial characters to separate it from typical Citellus. The first two North American species to be recognized were Citel- lus mexicanus and C. variegatus^ both described by Erxleben in 1777, and referred to the genus Sciurus. The former name was adopted by later writers, but the latter was allowed to lapse, through failure to distinguish the animal to which it was applied, for more than a 1938] REVISION OF THE GROUND SQUIRRELS 55 century, when Nelson (1898, p. 898) reinstated it by showing its ap- plicability to the Mexican rock squirrel, then commonly referred to under the name Spermo'philus Tnacrourus. A similar fate was in store for the Columbian ground squirrel, fii-st described by Lewis and Clark and named Arctomys columbianus in 1815 by Ord (pp. 292, 303), and again in 1817, Anisonyx hrachi- ura, by Kafinesque (p. 45). Baird (1875, p. 336) discussed the pos- sibility that this animal might be a prairie dog — the same as his Cynomys gunnisoni — but he pointed out certain important differ- ences. Allen, however (1877, p. 903), unhesitatingly pronounced it a prairie dog and it was so considered until Merriam (1891, p. 39), having procured specimens from the type region, showed it to be a ground squirrel. The next species to be described was the striped ground squirrel, named Sciurus tridecemllneatus by Mitchill in 1821. The following year. Sabine renamed this animal hoodii and described also two other species, the Franklin's and Richardson's ground squirrels, all re- ferred by him to the genus Arctomys. Long's expedition to the Rocky Mountains in 181^20 resulted in the discovery of two new species, Citellus grammurus and G. lateralis, both described by Say in 1823 in the genus Sciurus. Richardson, in 1825, described the big northern ground squirrel, O. parryii, in the genus Arctomys, and in 1829, two supposed new varieties of that species, erythrogluieia and phaeognatha; erythro- gluteia later proved to be a synonym of columbianus and phaeog- natha a synonym of parryii. The same year he named two species from the west coast region, heecheyi and douglasii. In 1833, Bennett described the Mexican spotted ground squirrel, C. spilosoma, and the Mexican rock squirrel under the name Spermo- philus macrourus ; the latter name, however, was later found to be a synonym of C. variegatus. Bachman, in 1839, described Citellus toionsendii from the plains of the Columbia, but the type specimen soon became so discolored with grease that its true characters could not be seen, and as a result the name townsendii has been misapplied by most recent authors (see explanation on p. 62). Audubon and Bachman, in 1842, described Spermophilus {^Citel- lus) annulatus, and in 1854, S. harrisii — both from unknown locali- ties— and in 1855, Baird added S. couchii from northern Mexico. Thus, when Baird's monograph appeared in 1857, there had been described 16 valid races of ground squirrels from North America, and of these all but three were treated in the monograph. Spermo- philus annulatus was thought to be an African species of Sciurus; S. macrourus of Bennett {^Citelhis variegatus) was provisionally in- cluded, while Ord's Arctomys columhianus was doubtfully referred to as a prairie dog. Baird added in this paper one new species — the round-tailed spermophile of the Southwest — Spermophilus tereti- caudus. In 1861, Ross named a form of Parry's spermophile, Arctomys Icennicottii (not now recognized), and Slack described the black rock squirrel of Texas, Spermophilus hucMeyi. Kennicott, in 1863, de- scribed four new forms, all of which are now recognized as valid: Spermophilus mollis, S. armatus, S. elegans, and S. obsoletus. 56 NORTH AMERICAN FAUNA [No. 56 J. A. Allen added Speniiophilus parryii hodiacensis in 1874 and S. tridecemlineatus paUidus in 1877. In his Monograph of the Rodentia (1877) 17 forms were treated, only three more than appeared in Baird's monograph issued 20 years earlier. Spermophilus townsendii was considered to be a variety of Hchardsonii, whereas elegans and armatus were both listed in the synonymy of that species. Parry's spermophile appeared under the name of S. empetra, while S. har- risii and S. lateralis were transferred to the genus Tamias. No more new species were described until 1888, when Merriam named Spermophilus heldingL Shortly after this, the modern period of activity in systematic mammalogy began, initiated largely by the extensive researches and explorations of Merriam and his collectors in the Biological Survey. At the beginning of this period, 1889, 30 forms of North American ground squirrels had been named, of which 25 are now considered valid races. Since that time, 91 addi- tional forms have been named, of which 69 are considered valid ; three new races are named in the present paper, making a total of 97 recognized races. Key to Subgenera a\ Molars relatively hypsodont; parastyle ridge on m^ and m^ joining the protocone with an abrupt change of direction. 6\ Metaloph on pm* continuous Citellus (p. 59) 6^ Metaloph on pm* not continuous Ictidomys (p. 106) c^ Molars relatively braehydont : parastyle on m* and m* rising evenly to join the protocone, without abrupt change of direction. 6\ Anterior upper premolar simple ; less than one-fourth the size of pm*. c^. Upper incisors relatively stout and distinctly recurved. -31). Skull: Aver- ago of 7 adults from typo locality: Greatest length, 33.5 (32.4-35.3) ; palatilar length, 16 (15.3-16.8) ; zygomatic breadth. 21.5 (21-23) ; cranial breadth, 16.3 (15.6-17.1) ; interorbital breadth, 6.7 (6.4-7) ; po.storbital constriction, 9.8 (9.2- 10.3) ; length of nasals, 12 (11.4-12.7) ; maxillary tooth row, 7.4. Remarks. — This small race of townsendii occupies a rather limited area in southeastern Idaho. The series from Big Lost River, which forms the basis of Merriam's ^^pessiinus^^ is intermediate in size between ^•Mu.'i. Vert. Zool. »»D. R. Dickey coll. »E. R. Warren coll. 12 Cleveland Mus. Nat. Hist. 1.54970—38 5 gg NORTH AMERICAN FAUNA tNo. 56 mollis and arteinesiae but nearer to the latter. _ The specimens appear slightly darker than typical artemesme but this may be due to wear, and in any case the difference is too slight to warrant recognition of the form by name. Specimens examined. — Total number, 31, as follows : Idaho: Berenice (Butte County), 2;" Big Lost River, 10; Birch Creek, 7; Blackfoot, 7; Pingree (Bingham County), 2;" Taber (Bingham County), 2;" Twin Lakes, Snake River Desert (20 miles north of Minidoka), 1. CITELLUS TOWNSENDII VIGILIS Meekiam Malhetjb Valley Gbottnd Sqtjireel Citellus canus vi gilts Merriam, BioL Soc. Wash. Proe. 26 : 137, May 21, 1913. Gitellus mollis vigilis Miller, U. S. Natl. Mus. Bull. 128 : 188, 1924. r^/^e.— Collected at Vale, Oreg. April 29, 1910, by Stanley G. Jewett; female adult, skin and skull, no. 168361, U. S. Natl. Mus., (Biological Survey collection) (orig. no. 30). Range. — Confined apparently to the lower part of Malheur Valley, Oreg., in the vicinity of Vale and Ontario and north in the Snake Eiver valley to Huntington. Zonal range: Upper Sonoran. External characters. — Largest of the races of G. townsendii; closely similar in coloration to G. t. canus., but averaging slightly more buffy ; darker (more buffy) than G. t. mollis. Granial characters. — Slmll similar to that of canus., but larger; averaging about the same length as that of mollis., but zygomata heavier and more widely spreading; rostrum relatively shorter and broader ; maxillary tooth row slightly shorter. Golor. — Worn tvinter pelage (April and May) : Upper parts smoke gray, sometimes faintly washed with pinkish cinnamon ; front of face with a rather extensive patch of cinnamon; sides of neck and body faintly (rarely strongly) washed with pinkish buff or pale pinkish buff ; front feet pinkish buff, hind feet creamy white ; tail above and below, cinnamon drab, mixed with fuscous, edged with white or buffy white, and with a subterminal patch of fuscous ; under parts creamy white, faintly washed with pinkish buff, the hairs fuscous at base, and this color often more or less prominent in mixture with the lighter tips. Summer pelage : Not represented. Measurements. — Average of 10 adults from Ontario and Vale, Oreg. : Total length, 226.2 (201-238) ; tail vertebrae, 44.4 (35-52) ; hind foot, 33.1 (31-35). Skull: Average of 13 adults from same localities: Greatest length, 38.3 (37.S- 39.6) ; palatilar length, 18.4 (17.5-19.5) ; zygomatic breadth, 25.5 (24.5-26.7) ; cranial breadth, 17.8 (17.2-18.4) ; interorbital breadth, 7.9 (7.3-8.4) ; postorbital constriction, 9.6 (8.9-10.5) ; length of nasals, 13.4 (12.8-13.8) ; maxillary tooth row, 7.7 (7.2-8.2). Remarks. — ^Living in a rich, fertile valley this race has developed markedly in size and robustness of skull. Its range apparently is quite limited, since the specimens a few miles to the westward of Vale are referable to canus and those on the east side of Snake River to mollis. Specimens examined. — Total number, 53, as follows : Oregon : Huntington, 4 ; Ontario, 23 ; Vale, 26. 13 Mus. Vert. Zool. 1938] REVISION OF THE GROUND SQUIRRELS 67 CITELLUS TOWNSENDII CANUS (Merriam) Gray Ground Squikkel Spermophilus mollis canus Merriam, Biol. Soc. Wash. Proc. 12 : 70, Mar, 24, 1898. [Citellus mollis] canus Trouessart, Cat. Mamm., Sup., p. 339, 1904. Type. — Collected at Antelope, Wasco Comity, Oreg., June 21, 1896, by Vern6n Bailey ; female adult, skin and skull ; no. 78681, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 5561). Range. — Eastern Oregon and extreme northwestern Nevada ; north to Antelope; west to Warmspring, Bend, and Summer Lake; south to Summit Lake, Nev. ; east to Catlow Valley and Cedar Mountains, Oreg. (fig. 1). Zonal range: Upper Sonoran. External characters. — Closely similar in color to C. t. mollis; tail and hind feet shorter. Similar also to G. t. vigilis but smaller; cimiamon patch on face paler. Cranial characters. — Skull similar in shape to that of vigilis but smaller. Compared with mollis : Shorter and relatively broader, the zygomata more wide spreading; bullae averaging smaller; rostrum relatively short and broad. Color. — Summer pelage (June 20-July 14) : Upper parts smoke gray, often with a faint wash of pinkish cinnamon and frequently more or less darkened by exposure of the subterminal fuscous areas of the hairs ; patch on front of face pinkish cimiamon ; sides of face, neck, and body sometimes faintly shaded with pinkish buff; tail and feet as in vigilis. Worn lointer pelage: Practically as in summer. Immature pelage: Similar to the adult pelage but often strongly shaded on sides of head and body with pinkish buff or cinnamon buff. Measurements. — Average? of 10 adults from Antelope, Gateway, and Prineville, Oreg.: Total length, 201.4 (190-217); tail vertebrae, 39.4 (37-42); hind foot, 30.7 (29-33). Skull: Average of 10 adults from Antelope and Gateway: Great- est length, 36.3 (34.6-38) ; palatilar length, 17.3 (16.5-18.5) ; zygomatic breadth, 23.9 (23.1-24.5) ; cranial breadth. 17.(5 (17-18.2) ; interorbital breadth, 7.5 (7-8) ; postorbital constriction, 10.1 (9.3-11) ; length of nasals, 12.9 (12.2-13.6) ; maxil- lary tooth row, 7.4 (7-7.8). Remarks. — This small gray race occupies most of the desert valleys of eastern Oregon except the extreme southeastern part, intergrading with the larger vigilis in the extreme eastern part of the State and with mollis in southern Malheur County and in northwestern Nevada. There are no records of its occurrence in northern Oregon, north of Antelope. Specimens examined. — Total number, 97, as follows : Nevada: Hot Springs, Thousand Creek, 3;" Summit Lake (Humboldt County), 1; Virgin Valley (Humboldt County), 3." Oregon: Antelope (7 miles east), 7; Baker (10 miles north), 3; ^' Barnes (Cook County), 1;" Bend, 11; Burns, 2; Cedar Mountains (Malheur County), 1; Christmas Lake (10 miles north), 1; Crane (Harney County), 6; Drewsey, 2; Fremont, 1; Gateway (Jefferson County), 15; Haycreek (Jefferson County), 5; Malheur Lake, 1; Narrows, 17; Plush (Lake County), 1; Prine- ville. 6; Riverside (Malheur County), 1; Rock Creek (Harney County), 4; Summer Lake, 2; Warmspring (Jefferson County), 3. "Mus. Vert. Zool. 1" Univ. Michigan Mus. Zool. 68 NORTH AMERICAN FAUNA [No. 56 CITELLUS IDAHOENSIS Mekeiam Snake Valley Ground Sqxjieeel (Pls. 23, B; 28, B) Citellus idahoensis Merriam, Biol. Soc. Wash. Proc. 26 : 135, May 21, 1913. Type.— Collected at Payette, Idaho, April 23, 1910, by Stanley G. Jewett; female adult, skin and skull, no. 168290, U. S. Natl. Mus. (Biological Survey collection) (orig. no. IT). Range. — North side of Snake River Valley, Idaho, from Payette to Glenns Ferry (fig. 2). Zonal range: Upper Sonoran. External charac- ters.— Similar to C. townsendii mollis but larger ; tail longer, and more tawny; up- per parts slightly darker and more dis- tinctlj'^ dappled. Com- pared with C. richard- sonii elegans: Size smaller ; tail shorter and darker ; coloration more grayish (less brownish or buffy). Cranial charac- ters.— Skull similar to that of G. tow-nsendii vigilis, but averaging larger ; nasals and molariform tooth row longer ; similar also to that of mollis but de- cidedly larger; audi- tory meatus longer. Color. — U nworn lointer pelage (April) : Upper parts pale smoke gray, faintly or moderately shaded with pinkish buff or cinnamon buff, with a slight indication of mottling ; a basal zone of deep mouse gray on the back, succeeded by a zone of smoke gray and then by a subterminal band of fuscous. Patch on front of face sayal brown; sides of body faintly washed with pinkish buff; front feet pinkish buff; hind feet buffy whitish; tail above, mixed pinkish cinnamon and fuscous edged with bufl'y white and with a subterminal band of fuscous ; tail beneath, cinnamon or sayal brown ; under parts grayish white, faintly washed with pinlc- ish buff, the bases of the hairs fuscous. Worn winter pelage (June 4) : General tone of upper parts pale snuff brown sprinkled with pinkish buff (the brownish tones due largely to exposure of the subterminal bands on the hairs). Figure 2. — ^Distribution of Citellus idahoensis. 1938] REVISION OF THE GROUND SQUIRRELS gQ Measurements. — Average of 20 adults from Payette and Nampa, Idaho: Total length, 245.9 (222-271) ; tail vertebrae, 59.2 (46-72) ; hind foot. 35.6 (33-38). Skull: Average of 16 adults from same localities: Greatest length, 40.1 (37.7-43.3) ; palatilar length, 19.4 (18-21.2) ; zygomatic breadth, 25.9 (25-26.8) ; cranial breadth, 18 (17-19) ; interorbital breadth, 8.2 (7.3-8.8) ; postorbital constriction, 9.7 (9-10.5) ; length of nasals, 14.3 (13.6-15.2) ; maxillary tooth row, 8.3 (7.8-9). Remarks. — G. idahoensis., although evidently belonging in the townsendii group, is clearly a distinct species, since it occurs in certain areas with C. t. mollis and maintains its characters without inter- gradation. It is best distinguished from C. t. mollis or 0. t. mgilis by its longer, broader, and more tawny tail, and by the more pro- nounced mottled effect on the upper parts. The skulls show ex- treme variation in size, and the smallest ones are scarcely distin- guishable from those of vigilis, though usually having a longer and heavier molar tooth row. So far as known, the species occupies a rather restricted range on the north side of the Snake River Valley in western Idaho. S'pecim.ens examined. — Total nimiber, 118, as follows: Idaho: Glenns Ferry, 3; Kuna (Ada County), 7; Mountain Home, 9; Nampa, 67; Orchard (Ada County), 6; Payette, 26. CITELLUS WASHINGTONI GROUP CITELLUS WASHINGTONI, SP. Nov. [Synonymy under subspecies.] General characters. — About the size of C. toionsendii mollis^' hind foot, 30-38 mm ; tail, 32-65 ; skull length, 35-41.4. Skull similar to that of C. t. toionsendii but relatively longer and narrower; smaller and relatively narrower than those of G. idahoensis and G. hrunneus. Upper parts smoke gray, flecked with whitish spots; tail mixed fuscous and grayish white, with blackish tip. CITELLUS WASHINGTONI WASHINGTONI, subsp. nov. Washington Ground SQxnBREi. (Pis. 1 ; 23, C; 28, C) Citellus townsendii Dice, Jour. Mammal. 1 : 18, 1919 ; Bailey, North Amer. Fauna 55: 151, 1936 (not Spermophilus townsendii Bachman). Type. — Collected at Touchet, Walla Walla County, Wash., May 18, 1891, by Clark P. Streator; male adult, skin and skull; no. |-^-|4, U. S. Natl. Mus. (Biological Survey collection^ (orig. no. 817). Range. — Southeastern Washington and nortliern Oregon; north to southern Adams County, Wash. ; east at least to the Idaho- Washing- ton boundary; south to Heppner, Oreg. ; west to Willows, Oreg. (fig. 3). Zonal range: Upper Sonoran. External characters. — Size medium; tail short; dorsal area dis- tinctly spotted, general tone grayish. Granial characters. — Skull similar to that of G. idahoensis but averaging smaller, and relatively narrower ; interorbital constriction narrower; postorbital processes narrower at base and very slender throughout ; ascending arms of premaxillae narrower than the nasals (about equal in idahoensis) ; auditory meatus much shorter. Com- 70 NORTH AMERICAN FAUNA [No. 56 pared with G. townsendii townsendii: Skull averaging larger, with relatively narrower brain case and interorbital region. Color. — Winter pelage (March) : General tone of upper parts pale smoke gray, faintly washed (except on head) with pinkish buff, the entire back flecked with squarish, grayish white spots averaging about 3 or 4 mm in breadth; patch on nose and front of face cinnamon; eyes surrounded with a narrow wliitish ring; sides of body very faintly washed with pale buff; feet whitish, tinged with pinkish buff, thighs pinkish cimiamon; tail above, grayish mixed with fuscous, with a subterminal band of fuscous black, tipped with buffy white; tail beneath, pinkish cimiamon sometimes mixed with fuscous and edged with buffy white; under parts grayish white, washed with pinkish buff, the bases of the hairs fuscous. Summer pelage (August) : Upper parts more brownish or fuscous than in winter, due appar- ently to wearing away of the whitish or buffy tips on the hairs and exposure of the subterminal brownish areas. Molt. — Numerous specimens taken in May and June are in badly worn pelage, but no clear indica- tions of the molt have been found in the series examined; probably, as in the case of other species, the pelage is renewed during the early part of sunnner. Measuretnents. — Average of 15 adults from Wallula, Pasco, and Toueliet, Wash. : Total length, 229.2 (212-245) ; tail vertebrae, 50 (40-65) ; hind foot, 35.3 (34-38). Skull: Average of 16 adults (5 males, 11 females) from same localities: Greatest length, 38.5 (36.8-41.4); palatilar length, 18.3 (17-20); zygomatic breadth, 24.8 (23.3-26.2) ; cranial breadth 17.2 (16.3-18.3) ; inter- orbital breadth, 7.4 (6.6-8.2) ; postorbital constriction, 9.2 (8-10.3) ; length of nasals, 13.8 (13-15.6) ; maxillary tooth row, 7.8 (7.3-8.3). Oregon specimens average larger than those from the type region ; average of 10 adult males from Pendleton and Willows: Greatest length, 39.4 (38.5-41.8) ; zygomatic breadth, 26 (24.8-27.5) ; cranial breadth, 18.1 (16.8-18.7). Weight. — Shaw (19251, p. 764) gives the weight of a male at time of enter- ing hibernation as 280 g ; on av/akening at the end of a period of 56 days the same animal weighed 221 g. Remarks. — This ground squirrel has been known for nearly half a century under the name Citdlus townsendii, but as shown on page 62, that name is applicable to another species. Therefore it has become necessary to provide a name for the species under consideration. The Washington ground squirrel is easily recognized among the American forms by its relatively short tail and conspicuous dorsal spotting. It is spotted much as in certain forms of G. spilosoma, but the latter have longer tails, harsher pelage, and differ widely in Figure 3. — Distribution of Citellus brunneus and sub- species of C. icashinytoni: 1, C. w. loringi ; 2, G. iv. ivashingtoni; 3, C. brunneus. 1938] REVISION OF THE GROUND SQUIRRELS 71 skull characters. The present form resembles G. guttatus of south- ern Russia rather closely in general appearance, but the available material does not permit of detailed comparison. There is, of course, no chance of close relationship between the two. The nearest relative of C. washingtoni is C. hrunneus of west- central Idaho, originally described by the writer as a subspecies of townsendii\^ = washing toni]^ but now believed to be a distinct species. The range of this species is separated from that of G. townsendii townsendiihj the Columbia River; in northern Oregon, luashingtoni occupies an area west of the Blue Mountains and east of John Day River, while G. tovnsendii canus occupies most of the semidesert regions of the State to the southward. The ranges of washingtoni and townsendii apparently do not overlap. Specimens examined. — Total number, 112, as follows : Oregon: Cold Springs (Umatilla County), 1; Heppner, 9; Pendleton, 17; Pilot Rock (Umatilla County), 3; Umatilla, 1; Vinson (Umatilla County), 2; Willows (Gilliam County), 6; Willows Junction, 1. Washington: Almota (Whitman County), 4; Columbia River, 1;" Riparia (Whitman County), 1; Othello (Adams County), 1;" Pasco, 19; Pataha (Columbia County), S;" Touchet, 27; Wallula, 8;" Wawawai, 2." CITELLUS WASHINGTONI LORINGI, suESp. nov. Loeing's Ground Squirrel Type. — Collected at Douglas, Wash., August 1, 1897, by J. Alden Loring; male adult, skin and skull; no. 89805, U. S. Natl. Mus. (Bio- logical Survey collection) (orig. no. 4547). Range. — Plains of east-central Washington, south and east of the Columbia River, including most of Douglas, Grant, Lincoln, and Adams Counties; east to Spokane County (fig. 3). Zonal range: Upper Sonoran. Gharacters. — Similar in color and cranial characters to G. w. wash- ingtoni but smaller. Measurements. — Average of 10 adult males from type region (Douglas, Waterville, Baird, Farmer, Coulee Citv) : Total length, 203 (185-224) ; tail vertebrae, 39.6 (32-48); hind foot, 30.8 (30-33). Skull: Average of 10 adult males from same localities: Greatest length, 36.4 (35-38); palatilar length, 17.5 (17-18) ; zygomatic breadth, 23.4 (22.6-24.5) ; cranial breadth, 17.2 (16.4-18) ; interorbital breadth, 7 (6.4-7.7) ; postorbital constriction, 9.7 (9-11); length of nasals, 13.4 (12.,S-14.7) ; maxillary tooth row, 7.7 (7.5-8). Remarks. — This race, occupying the high plains at the northern limit of the range of the species, is characterized mainly by being smaller than the typical form. Specimens from Sprague, Wash., are intermediate between Joringl and the typical race. Specimens examined. — Total number, 20, as follows: Washington: Baird (Douglas County), 3; Cheney, 1; Coulee (Grant County), 2; Douglas, 2; Farmer (Douglas County), 2; Harrington, 1; Mansfield, 1; Moses Coulee (Douglas County), 1; Sprague, 5; Waterville, 1; Wil- bur, 1. >"Type, Acad. Nat. Sci. Philadelphia. *^ TIniv. Michigan Mus. Zool. " Four in Univ. Michigan Mus. Zool. "Field Mus. Nat. Hist. 72 NORTH AMERICAN FAUNA [No. 56 CITELLUS BRUNNEUS Howell Idaho Spotted Ground Squiekel (Pis. 23, D; 28, D) Citellus townsendii drunneus Howell, Biol. Soc. Wash. Proc. 41: 211, Dec 18, 1928. Type. — Collected at New Meadows, Adams County, Idaho, July 11, 1913, by L. E. Wyman; female adult, skin and skull, no. 201963, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 178). Range. — West central Idaho, in Washington, Adams, and Valley Counties ; limits of range unknown (fig. 3) . Zonal range: Transition and Upper Sonoran. External characters. — Similar to C. washingtoni wasliingtoni but color of upper parts more brownish (less grayish) and the dorsal spots smaller; cinnamon patch on face darker and more extensive; tail longer and darker (more blackish) ; ears much larger, raised conspicuously above the crown. Compared with G. idahoensis: Upper parts more brownish and distinctly spotted; tail with more black; ears larger. Cranial characters. — Skull similar to that of washingtoni but aver- aging larger and relatively broader, especially the rostrum and the postorbital region; nasals longer; last upper molar with posterior Joph practically obsolete. Compared with idahoensis: Skull averag- ing slightly smaller but broader across postorbital region; nasals larger (both longer and broader) ; audital bullae smaller; external meatus shorter. Color. — Summer pelage (July) : General tone of upper parts smoke gray, more or less heavily washed on the back with pinkish cinnamon or sayal brown, and moderately sprinkled with small, quadrangular spots of grayish white; front of face with a rather extensive patch of sayal brown ; eyes surrounded with a broad ring of creamy white ; sides of neck and body faintly washed with pinkish buff ; feet pinkish buff ; thighs pale russet ; tail above, dark sayal brown at base, shaded on distal portion with fuscous black and all sprinkled with grayish Avhite ; tail beneath, cinnamon, shaded with grayish white and fuscous, and edged with cinnamon buff; under parts grayish white, shaded with pinkish buff. Measurements. — Average of 13 adults from type region (New Meadows, Mid- vale, Van Wyck, Goodrich, and Weiser) : Total length, 232.5 (214-252) ; tail vertebrae, 56.7 (51-61) ; hind foot, 34.2 (33-37) ; ear from notch, 10.5 (&-12). Skull: Average of 5 adult males from Weiser and Midvale, Idaho : Greatest length, 40.1 (38.7^0.8) ; zygomatic breadth, 25.5 (24.9-26.1) ; palatilar length, 18.6 (18-19) ; cranial breadth, 18.4 (18.1-18.5) ; interorbital breadth, 8.3 (7.5- 9.2) ; postorbital constriction, 10.9 (10.4-11.6) ; length of nasals, 14.8 (13.7-16.1) ; maxillary tooth row, 8.4 (8.1-8.8). Average of 3 adult females (including type) : Greatest length, 37.3 (36.4-38.2) ; palatilar length, 17.3 (17-18) ; zygomatic breadth, 23.8 (23.4-24.1) ; cranial breadth, 17.8 (17.2-18.6) ; interorbital breadth, 7.8 (7.6-8.1) ; postorbital constriction, 10.4 (9.5-11.2) ; length of nasals, 13.4 (33.1-13.8) ; maxillary tooth row, 7.9 (7.5-8.2). Remarks. — This well-marked species apparently has a rather re- stricted distribution in west-central Idaho, where it meets or slightly overlaps the range of C. townsendii mollis (at Weiser). It is readily distinguished from both idahoensis and mollis by its distinct dorsal spotting and its large ears. 1938] REVISION OF THE GROUND SQUIRRELS 73 Originally described by the writer as a subspecies of C. townsendii \_— leashing toni], it appears on more detailed comparison to be a dis- tinct species, distinguished from washingtoni by larger ears, longer and darker tail, smaller dorsal spots, and by the skull characters pointed out above. Specimens examined. — Total number, 14, as follows: Idaho: Goodrich (Adams County), 1; Midvale (Washington County), 3; New Meadows (Adams County), 2; Van Wyck (Valley County), 2; Weiser, 6. CITELLUS RICHARDSONn GROUP CITELLUS RICHARDSONII (Sabine) [Synonymy under subspecies] SpecifiG characters. — ^Size medium to large ; hind foot 39.5-48 mm ; tail 65-100 ; skull length 42-48.6. Dorsal outline of skull convex, the highest point being between the postorbital processes; brain case harrow and deep, much constricted anteriorly; postorbital processes long, slender, and decurved; interorbital constriction pronounced; zygomata heavy and broad, widely expanded posteriorly, narrowing anteriorly ; rostrum moderately narrow ; nasals ending nearly on the j)lane of the posterior ends of premaxillae, or shorter; antorbital canal suborbicular ; upper tooth rows slightly convergent poste- riorly ; auditory bullae rather small, low and broad ; auditory meatus slightly produced; upper incisors moderately slender and nearly straight. Coloration of upper parts drab or smoke gray, more or less shaded with fuscous and dappled with cinnamon buff; under parts pale buff or cinnamon buff; under side of tail clay color, cinnamon buff, or sayal brown. CITELLUS RICHARDSONII RICHARDSONII (Sabine) Richardson's Gbound Squirrel (Pis. 2; 25, F; 30, F) Arctomys richardsonii Sabine, Trans. Linn. Soc. London 13 : 589, 1822. Arctomys (Spermophilus) richardsonii Richardson, Fauna Boreali-Amer., p. 164, 1829. Spermophilus richardsonii F. Cuvier, Sup. Sl I'hist. natur. Buff on 1 : 323, 1831. [Citellus] richardsoni Trouessart, Cat. Mamm., Sup., p. 338, 1904. Type (lectotype).^^ — Collected at Carlton House, Saskatchewan, by Sir John Richardson; no. 63a, British Museum. Range. — Plains of southern Alberta, southern Saskatchewan, south- western Manitoba, northern and central Montana, North Dakota (except southwestern part), and northeastern South Dakota; north to the North Saskatchewan Eiver; east to the Red River Valley, N. Dak., Big Stone Lake, S. Dak,, and the western edge of Minne- sota; south to east-central South Dakota (Jerauld County), and southwestern Montana (Gallatin and Park Counties) ; west to the foothills of the Rocky Mountains in Alberta and Montana (fig. 4). Zonal range: Transition. External characters. — Size large; hind foot, 43-47 mm; tail about one-fourth the total length; ears broad and low (2-4 mm above "Selected by O. Thomas (1927, p. 545). 74 NORTH AMERICAN FAUNA [No. 56 crown) ; coloration above nearly uniform buffy or drab, with slight "dappling" ; under parts deep buff in summer pelage. Graniaf^ characters. — As given under specific characters ; compared with* 0. r. elegans^ the skull is larger, with longer and relatively narrower rostrum. Color. — Fresh summer pelage (July) : General tone of upper parts pinkish buff or cinnamon buff, shaded with fuscous (caused by ex- posure of the subterminal bases of the hairs), the posterior part of back showing a distincthf "dappled" effect; nose with a large patch of cinnamon; eye ring light buff; sides of head and neck and front of fore le^s cinnamon buff or clay color; sides of body and under parts pinkish buff or cinnamon buff ; hind feet pinkish buff ; tail above, fuscous black, mixed with pinkish buff and broadly edged with the same; tail beneath, cinnamon buff or clay color, edged with pinkish buff. In worn pelage much of the buffy tone of the upper parts is lacking, the general effect being near smoke gray. Molt. — Apparently the molt may occur at any time in the spring or summer. Specimens taken in April at Choteau, Mont., are in a much -worn pelage and one— a breeding female — shows a patch of new hair extending along the middle of the back from the head nearly to the rump. An- other adult female from Blackfoot, Mont., June 12, is in similar condition of molt. An adult fe- male from Wingard, Saskatchewan, July 15, is much worn on the anterior half of the body and shows new pelage covering the posterior half to the middle of the back. Measurements. — Average of 16 adults (7 males, 9 females) from type locality: Total length, 2S5.4 (277-306) ; tail vertebrae, 73.8 (65-83) ; hind foot, 44.9 (43-47). Skull: Average of 7 adult males from type locality: Greatest length, 47.7 (47.3^8) ; palatilar length, 23.7 (23-25) ; zygomatic breadth, 31.9 (30.5-33.5) ; cranial breadth, 20.2 (19.9-20.8) ; interorbital breadth, 9.9 (9.5- 10.6) ; postorbital constriction, 11.4 (10.8-11.9) : length of nasals, 17.4 (17-18) ; maxillary tooth rovs^, 10.4 (10.2-10.7). Average of 8 adult females from type locality: Greatest length, 46.5 (45.1-48.4); palatilar length, 23.1 (22.5-24): zygomatic breadth. 30.4 (29.5-31.2) ; cranial breadth, 19.6 (19-20.9) ; interorbital breadth, 9.5 (8.8-10) ; postorbital constriction, 11.1 (10.8-11.5) ; length of nasals, 16.9 (16-18.1); maxillary tooth row, 10.4 (10-10.9). Average of 6 adults (3 males, 3 females) from Choteau County, Mont. : Greatest length, 48.1 (46.5- 49.9) ; palatilar length, 24.4 (23.2-26) ; zygomatic breadth, 32.5 (31.5-33.1) ; cranial breadth, 20 (19.2-20.8) ; interorbital breadth, 9.8 (8.7-11.7) ; postorbital constriction, 10.6 (9.8-11.2) ; length of nasals, 17.8 (17.2-18.7) ; maxillary tooth row, 10.5 (10.1-11). Weight. — In spring, 11 to 13 ounces ; in fall 16 to 11 V2 ounces (Bailey, 1926, p. 58). Remarhs. — Richardson's ground squirrel has an extensive range in the Great Plains region of southern Canada, Montana, and the Da- FiGDKE 4. — Distribution of tlie subspecies of Citellus rich- ardsonii: 1, C r. richardsonii ; 2, C. r. elegansj 3, C. r. nevadensis. 1938] REVISION OF THE GROUND SQUIRRELS 75 kotas. The species apparently has extended its range southward in South Dakota in recent years and is now found regularly along the northern border of Jerauld, Sanborn, Miner, and Lake Counties, with several outlying records of occurrence in Hanson County in 1932. It is reported also to have extended its range into western Minne- sota; Surber (1932, p. 58) states that colonies have recently been es- tablished in Norman County and near Enok, Kittson County; Louis EjQowles reports that these ground squirrels invaded the western borders of the counties of Traverse, Big Stone, and Lac qui Parle in 1934. In Gallatin County, Mont., richardsonii grades into the smaller and darker race, elegans^ which occupies most of the southwestern corner of the State. Specimens examined. — Total number, 349, as follows : Alberta: Calgary, 8;" Red Deer, 7. Manitoba: Brandon (IS miles east) , 1 ;" Carberry, 56 ; Petrel (Norfolk District) , 1. Montana: Blackfoot (Glacier County), 11; Blackfoot Agency (Glacier County), 6; Big Belt Mountains (Meagher County, south of Fort Logan), 3; Big Timber Creek, Crazy Mountains ( Sweetgrass County ) , 4 ; Birch Creek (Teton County), 4; Bozeman, 10; Bruno (Meagher County), 3;'^ Buffalo (Fergus County), 1; Chief Mountain (Glacier County), 1; Choteau, 11; Dry Creek (Gallatin County), 2; East Gallatin River, 4; Flat Willow Creek, 3.24 Yovt Ellis (near Bozeman), 1; Frenchmans River (at international boundary), 4; Glasgow, 5; Great Falls, 1; Grafton (Judith Basin County), 1; Johnson Lake (Roosevelt County), 2; Lewistown, 3; Livingston, 5; Manhattan (Gallatin County), 2; Martinsdale (10 miles east, Wheatland County), 2; Milk River (at mouth, at 49°, and at Two Forks), 5; Moccasin Mountains (Fergus County), 3; Philbrook (Judith Basin County), 1; Ring- ling (10 miles south, Meagher County), 3;'^ Roy (Fergus County), 1; St. Mary, Glacier National Park, 11;=^ Sedan (Gallatin County), 2;'^ Shelby Junction, 5; Summit (near Ringling, Meagher County), 1; Sun River Cross- ing (Cascade County), 1; Teton (Choteau County), 1; Three Buttes (on International boundary, Hill County), 15; Toston (Broadwater County), 1;-^ Townsend (Broadwater County), 3;" Tyler (Fergus County), 1; Ubet (Wheatland County), 5; West Gallatin River (Lower Basin), 1; West Gallatin and Spanish Canyons (Gallatin County), 3.^ North Dakota: Ashley, 1; Bismarck, 11; Bottineau, 8; Bowdon, 2;" Buford (Williams County), 6; Crosby, 1; Devils Lake, 15; Drayton, 6; Ellendale, 1 ; Grafton, G ; Hankinson, 1 ; Kenmare, 1 ; LaMoure, 6 ; Larimore, 2 ; Lisbon, 1; Lostwood (Mountrail County), 1; Pembina, 2; Rush Lake (Cavalier County), 2; St. John (Rolette County), 2; Starkweather (Ramsey County), 1; Stump Lake (Nelson County), 1 ;"" Towner, 1; Turtle Creek (near Wash- burn), 1; Turtle Mountains, 2; Washburn, 4. Saskatchewan : Carleton, 5 ; Indian Head, 3 ; Livelong, 1 ; *" Moosejaw, 3 ; Win- gard, 20. South Dakota : Aberdeen, 2 ; Frederick, 4 ; Wahvorth County. 1. 22 Five in collection of C. B. Garrvtt. 23 Kansas Univ. Mus. 2< Montana Slate College. 25 Univ. Michigan Mus. Zool. 2« William T. Shaw coll. 27 Carnegie Mus. 76 NORTH AMERICAN FAUNA [No. 56 CITELLUS RICHARDSONII ELEGANS (Kennicott) Wyoming Ground Squireel (Pis. 25, E; 30, E) Spermophilus elegans Kennicott, Acad. Nat. Sci. Phila. Proc. .186.3: 158. ISpermophilus ricliardsoni] var. elegans Allen, Boston Soc. Nat. Hist. Proc. 16: 292, 1874. ISpermophilus richardsoni] var. townsendi Allen, Monog. North Amer. Rodentia, p. 850, 859, 1877 (part). [Citellus] elegans Trouessart, Cat. Mamm., Sup., p. 339, 1904. Cotypes. — Collected at Fort Bridger, Wyo., April and May 1858, by C. Drexler; female, skin and fragments of skull, no. |||^ ; male, skin and part of skull inside, no. 3480; skin no. 5955 ; skin (in alcohol) and skull, no. ffff ; alcoholics, nos. 5951, 5952, 5953, 5954; also, a few other fragments in U. S. Natl. Mus. (Lyon and Osgood, 1909, p. 165). Range. — Southwestern Montana, southeastern Idaho, southern Wyoming, and northwestern Colorado; north to Madison and Beaverhead Counties, Mont., and northwestern Converse County, Wyo.; east to extreme southeastern Wyoming; south to Leadville, Colo.; west to Custer County (Big Lost River Valley), Idaho (fig. 4) . Zonal range : Mainly Transition. External characters. — Similar to C. r. richardsonii but smaller, with shorter hind feet; coloration of upper parts in summer less buffy (more grayish or brownish) ; under parts and sides of head and shoulders paler in summer pelage; tail usually darker and more blackish beneath, but with paler edgings. Cranial characters. — Skull similar to that of richardsonii but smaller; rostrum shorter and relatively broader; nasals shorter. Color. — General tone of upper parts light drab, more or less flecked with light pinkish buff, some specimens showing a decided pinkish or brownish tone on the middle of the back, the head and shoulders frequently more or less washed with smoke gray; nose cinnamon buff, clay color, or pinkish cinnamon; eye ring white or buffy white ; feet pinkish buff or ivory yellow ; tail above, similar on basal portion to the back, the terminal half broadly bordered with fuscous black and edged with pale buff ; tail beneath, cinnamon buff or pale cinnamon, bordered on terminal portion with fuscous black ; lower sides and under parts cartridge buff. Measurements. — Average of 10 adults from Fort Bridger and New Fork of Green River, Wyo.: Total length, 262.3 (253-272) ; tail vertebrae, 72.9 (66-78) ; hind foot, 40.7 (39.5-43). Skull: Average of 12 adults (9 males, 12 females) from vicinity of type locality (Fort Bridger, Evanston. Cumberland, Lone Tree) : Greatest length, 43.1 (42^4.8) ; palatilar length, 20.9 (20-22.2) ; zvgo- matic breadth, 28.8 (27.5-30) ; cranial breadth, 19.7 (18.7-20.5) ; interorbital breadth, 9.3 (8.5-10) ; postorbital constriction, 11.3 (10.5-11.7) ; length of nasals, 15.3 (14.7-16.1); maxillary tooth row, 9.4 (9-9.7). Remarks. — The Wyoming ground squirrel was originally de- scribed by Kennicott as a distinct species. Allen (18YT, p. 850), cor- rectly associated it with C. richardso^iii as a variety, but misapplied Bachman's name townsendii to it. It continued to be known by that name until 1891, when Merriam revived Kennicott's name for it and suggested that it might prove to be a subspecies of richardsonii. The material now available shows this to be the case, intergradation be- tween the two forms occurring in Gallatin County, Mont. Speci- mens of elegans in winter pelage are scarcely distinguishable from 1938] REVISION OF THE GROUND SQUIRRELS 77 comparable specimens of C . r. ridiardsonii^ except by their smaller size, but in summer pelage elegans is decidedly grayer and less buffy. Specimens examined. — Total number, 229, as follows : Colorado: Canadian Creek (North Park), 3; Coulter (Grand County), 6; Elk- horn (Larimer County, near Log Cabin), 2; Estes Park, 1;^ Fairplay, 2; Fish Creek (Routt County), 2; Fort Collins (Buckhorn Ranger Station), 6; Garo (Park County), 1; Leadville (10 miles south), 2;^ Mount Whitely (Grand County), 1; Rabbit Ear Mountains (Jackson County), 1; Sopris National Forest (west of Thomasville), 1; Steamboat Springs (15 miles west), 3; Wolcott (Eagle County), 1.=° Idaho: Birch Creek (Clark County), 5; Dickey (Custer County), 10; Forney, 1: Henry Lake, 1; Lemhi Mountains (west of Junction), 1; Montview, 1; Patterson (Bingham County), 3; Pleasant Valley (Clark County), 1. Montana: Alder, 1; Big Hole Bench (west of Wisdom, Beaverhead County), 1; Dillon, 14 ; ^ Ennis Lake, 2 ; Harrison, 3 ; Lakeview, 2 ; Lower Bedrock Lake (Beaverhead County), 1;'* Pony (Madison County), 1; Red Bluff (Madi- son County), 1; Virginia City, 5; Wisdom (9 miles north, Beaverhead County), 3." Wyoming: Altvan (Laramie County), 1; Bear Creek (Albany County, near Eagle Peak), 1; Big Piney (Sublette County), 1; Big Sandy (Sublette County), 2; Bitter Creek, 5;'^ Bridger Pass (Sweetwater County), 7; Bridger Peak, Sierra Madre Mountains, 1 ; Cheyenne, 8 ; Cokeville, 6 ; Cum- berland, 9; Evanston, 4: Fort Bridger (Uinta County), 18; Fort Russell (Laramie County), 6; Fort Saunders (=Laramie), 1; Fort Steele (Carbon (IJounty), 2; Fossil (Lincoln County), 8; Green River (City), 3; Green River (at mouth of New Fork), 5 ; Islay (Laramie County), 2 ; Kemmerer, 1 ; Kin- ney Ranch (Bitter Creek. Sweetwater County), 3; Laramie, 1; Laramie River, 1 ; Laramie Mountains, 3 ; Little Medicine Bow River (Carbon County), 1; Little Piney Creek (Sublette County), 1; Lonetree (Uinta County), 9; Medicine Bow ^Mountains, 2; Mountainview (Uinta County), 2; New Fork, Green River (Lander Road), 4; Opal (Lincoln County), 1; Pinedale, 2; Poison Spider Creek (Natrona County), 1; Pole Mountain (15 miles southeast of Laramie), 2; Rawlins, 2; Riverside (Carbon County), 1; Sage (Lincoln County), 4; South Pass City (Fremont County), 1; Supe- rior, 4; Woods P. O. (Medicine Bow Mountains, Albany County), 4. CITELLUS RICHARD SONII NEVADENSIS Howell Ne:\-ada Ground Squirrel Citellus elegans nevadensis Howell, Biol. Soc. Wash. Proc. 41: 211, Dec. 18, 1928. Type. — Collected at Paradise, Plumboldt County, Nev., March 3, 1908, by Stanley E. Piper; female adult, skin and skull; no. 156788, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 112). Range. — Northern Nevada, extreme southeastern Oregon, and ex- treme southwestern Idaho; from Paradise Valley, east to Metropolis and south to Kuby Valley, Nev. (fig. 4). Zonal range: Upper Sonoran and Transition. External characters. — Similar to C. r. elegans but larger, with longer tail and hind feet; upper parts averaging more grayish (less brownish), especially on head and shoulders; under parts darker buff. Compared with G. heldingi oregonus: Size larger; upper parts paler and more buffy (less reddish) ; under parts more buffy; tail paler and less reddish beneath. Cranial characters. — Skull similar to that of elegans but averaging decidedly larger; postorbital constriction averaging less. Compared 28 Univ. of Michigan Mus. Zool. ™ State Hist. Soc. of Colorado (Denver). *> Eight in Kansas Univ. Mus. Nat. Hist. »i Montana State College. aa Field Mus. Nat. Hist. 78 NORTH AMERICAN FAUNA tNo. 56 with G. r. richardsonii : Skull averaging slightly larger, with broader rostrum, nasals, and audital bullae ; tooth row shorter. Color. — (Type, March 3) : Patch on front of face mikado brown (varying in other specimens to wood brown or pinkish cinnamon) ; head and shoulders smoke gray, shaded with fuscous ; eye ring broad, buffy white ; back smoke gray shaded with cinnamon buff, the median area darkened with fuscous; feet pinkish buff; tail above, mixed fuscous and pinkish buff, edged with pale buff; tail beneath, sayal brown, tipped with fuscous; lower sides and under parts cinnamon buff, shading to pale buff on chin and throat. Measurements. — Type (? ad., from dry skin) : Total length, 337; tail verte- brae, 100; hind foot, 47. Average of 9 adults from Ruby Valley, Skelton, and McDermitt, Nev. : Total length, 291.1 (270-307) ; tail vertebrae, 88.1 (7&-100) ; hind foot, 46.1 (42--48). BUull: Average of 6 adults (3 males, 3 females) from Paradise, Metropolis, and McDermitt, Nev. : Greatest length, 47 (44.7-48.6) ; palatilar length, 23 (22-24) ; zygomatic breadth, 31.3 (29.9-32.4) ; cranial breadth, 20.9 (19.6-21.7) ; interorbital breadth, 10 (9.2-11.6) ; postorbital con- striction, 10.6 (9.7-11.5) ; length of nasals, 17.7 (17-18.6) ; maxillary tooth row, 9.6 (9.3-10.3). Remarks. — The Nevada ground squirrel is fully as large as typical richardsonii but is grayer and less buffy and the tail is darker and more tawny beneath. It undoubtedly intergrades with elegans, but its range as at present known appears to be isolated from the range of that race. It overlaps the range of oregonus., occurring often in the same localities, but the two are quite distinct. Specimens examined. — Total number, 33, as follows : Idaho: Riddle (Owyhee County), l.** Nevada: Elko, 9; Metropolis, 5; Mountain City (Elko County), 2; Paradise (Humboldt County) , 2 ; Ruby Valley, 5 ; Skelton (30 miles south of Elko) , 2. Oregon: Malheur County (near McDermitt, Nev.), 4; Rattlesnake Creek (at head, Malheur County), 3. CITELLUS ARMATUS (Kennicott) Uinta Gkound Squirrel (Pis. 23, F; 28, F) Spermophiliis armatus Kennicott, Acad. Nat. Sci. Phila. Proc. 1863: 158. [Cifellus] armatus Trouessart, Cat. Mamm., Sup., p. 339, 1904. Cotypes. — Collected in the foothills of the Uinta Mountains, near Fort Bridger, Wyo., April to June 1858, by C. Drexler; nos. 3464 and 3476, skins [fragmentary] with skulls inside; nos. 4794, 4808, 4809, fragmentary skulls ; nos. 5958, 5959, 5960, alcoholics (Lyon and Osgood, 1909, p. 163). Range. — Mountains and foothills of western Wyoming, extreme southwestern Montana, southeastern Idaho, and northern and central Utah; north to Beaverhead, Madison, Gallatin, and Park Counties, Mont. ; east to the eastern foothills of the Shoshone and Wind River Mountains, Wyo. ; south to Fish Lake Plateau, Utah ; west to Dono- van, Mont., Mount Harrison, Cassia County, Idaho, and the Raft River Mountains, Utah (fig. 5). Zonal range: Canadian and Transi- tion. Ea;ternal characters. — Similar to G. richardsonii elegans^ but slightly larger, with longer hind feet, tail of nearly the same length ; ears larger; upper parts decidedly darker; tail more grayish (less «Mus. Vert. Zool. 1938] REVISION OF THE GROUND SQUIRRELS 79 buffy) beneath. Compared with C. teldingi oregonus: Closely sim- ilar in size and coloration, but dorsal region slightly darker, the rmnp and thighs more tawny (less grayish) ; tail grayish rather than reddish beneath, the bordering hairs more buffy (less grayish). Cranial characters. — Skull similar to that of G. r. richardsonU but averaging slightly longer, and narrower across zygomata; cranium, interorbital region, and rostrum broader, but postorbital constriction less ; audital bullae broader, with longer meatus; nasals slightly longer ; max- illary tooth row shorter. Compared with elegans: Decid- edly larger, with broader rostrum and interorbital region, and longer and broader nasals. Com- pared with C. r. ne- vadensis: Similar in size, but averaging broader across zygo- mata; brain case and audital bullae broader. Compared with C. h. oregonus: Skull slightly larger ; nasals averaging broader at posterior end. Color. — ( Fresh pelage, June 12) : Head, front of face, and ears cinnamon, sprinkled on crown with gray; sides of face and neck pale smoke gray; eye ring cartridge buff; front legs cinnamon buff, shad- ing to pinkish buff on feet ; general tone of dorsal area sayal brown or cinnamon buff, the hairs tipped with pinkish buff, bases of the hairs fuscous; sides paler than back, mixed cartridge buff and fus- cous; thighs cinnamon; hind feet pinkish buff; tail, above and below, fuscous black, mixed with pale buff or buffy white, and edged with pinkish buff; under parts pinkish buff, shaded with buff'y white. Variation. — The intensity of the brownish color on the back varies considerably in different individuals; certain specimens, taken botli in midsummer and early spring, have the brownish tone much reduced, the hairs on the median dorsal area being pinkisli buff and the wliole back and sides washed with grayish white. Two specimens from Mountainview, Wyo., are uniform blackish brown all over. Molt. — The molting period is not clearly shown in the specimens examined, but probably in most individuals the molt occurs in June, or sometimes in May. A male from Hamsfork, Wyo., taken May Fiauui: 3. — Distribution of Citcllus annatus. go NORTH AMERICAN FAUNA [No. 56 17, is in badly worn pelage, and shows a few small patches of new hair on the back. A nursing female from Spring Valley, Wyo., June 9, is likewise in a much worn pelage, with new hair covering the head and fore back. An adult male from Cooke, Mont., August 11, shows worn hair on the anterior half of the body and a fuller, unworn pelage on the posterior half. Measurements. — ^Average of 12 adults from vicinity of tyue locality : Total length, 294 (280-303) ; tail vertebrae, 72.6 (63-81) ; Mnd foot, 43.9 (42^5.5) ; ear from notch, 11.2 (10-12). Skull: Average of 7 adult males from south- western Wyoming and Barclay, Utah: Greatest length, 47.8 (46.3-48.5) ; palat- ilar length, 23.2 (22.5-24) ; zygomatic breadth, 31 (30-31.8) ; cranial breadth, 20.7 (19.2-21.5) ; interorbital breadth, 11 (10-11.3) ; postorbital constriction, 10.9 (10.4-11.5) ; length of nasals, 17.8 (16.4-18.4) ; maxillary tooth row, 9.7 (9.3-10). Average of 6 adult females from Fort Bridger and Spring Valley, Wyo.: Greatest length, 46.5 (45.6-48) ; palatilar length, 22.2 (22-23) ; zygomatic breadth, 30.2 (29.6-30.8) ; cranial breadth, 20.1 (19.8-20.4) ; interorbital breadth, 10.2 (9.4-11.3) ; postorbital constriction, 11.3 (10-12.3) ; length of nasals, 17.2 (16.&-17.9) ; maxillary tooth row, 9.8 (9.4-10.2). Remarks. — The Uinta ground squirrel is a distinct species, occupy- ing a rather limited area in the mountains from southern Montana south to Utah. It most nearly resembles oregonus, but the two are quite distinct and so far as known their ranges do not meet. The range of armatus meets and slightly overlaps that of elegans in parts of Montana and Wyoming, but in general this species occurs at higher altitudes and in more heavily wooded areas than does elegans. In some localities, however, as at Pinedale and Cokeville, Wyo., the two species occupy the same ground. Specimens examined. — Total number, 263, as follows: Idaho: American Falls, 1; ^ Arco (Butte County), 4; '^ Big Hole Mountains, 1; Blackfoot, 4; Blackfoot Mountains, 1; Clifton (Franklin County), 1; Elba (Cassia County), 1;^° Irwin (10 miles southeast, Bonneville County), 5; Malta (Cassia County), 1;^° Montpelier, 7; Mount Hai-rison (Cassia County), 1;^° Pahsimeroi River (head, Custer County), 1;^ Pocatello, 6; Shelley, 1; Swan Lake (Bannock Courity), 6; Teton Canyon, 1; Warm River (Fremont County), 1.^* Montana: Cooke (Park County), 11; Donovan (Beaverhead County), 1; Ennis Lake (Madison County), 2; Lakeview (Beaverhead County), 13; Spanish Creek (Gallatin County), 3; Virginia City (Eight-mile Spring), 4; Vir- ginia City (20 miles south), 3 ; Ward Peak (Tobacco Root Mountains, Mad- ison County), 6; West Boulder Creek (18 miles southeast of Livingston), 3; West Gallatin River (West Fork, Gallatin County), 4; West Gallatin and Spanish Canyons (Gallatin County), 9.'" Utah: Barclay (Salt Lake County), 8; Blacksmiths Fork (Cache County), 1; Big Cottonwood Canyon (Salt Lake County), 1;" Bountiful, 1; Currant Creek (Wasatch County), 2; Fairview (Mammoth Ranger Station), 2; Farmington, 2; Fish Lake (Sevier County), 1; Fruitland, 3;*^ Hyde Park (Cache County), 1; Laketown (Rich County), 2: Lakota, Bear Lake, 1 ;^' Logan Canyon (Cache County), 1;'^ Mantua (Box Elder County), 1;^ Mount Pleasant, 1; Mount Timpanogas (Utah County), 2;^ Ogden"(Ogden Can- yon), 1; Park City, 17; Raft River Mountains, 1;'' Salt Lake City (Fort Douglas), 3; Sardine Canyon (Cache County), 2;'* Strawberry Valley (Du- chesne County), 9; Wellsville, 4. Wyoming: Afton (Lincoln County), 11; Border (Lincoln County), 5; Clarks Fork (opposite Crandall Creek, Park County), 1 ; Cokeville, 6; Daniel (Sub- lette County), 13; Evauston, 4; Fort Bridger, S; Gros Ventre Mountains ** Donald R. Dickey collection. s^Mus. Vert. Zool. 88 Montana State College, Bozeman. ^ Acad. Nat. Sci. Philadelphia. ^ Brigham Young Univ. s9 Utah State Agr. College. *i Carnegie Mus. 1938] REVISION OF THE GROUND SQUIRRELS 81 (Waterdog Lake), S;^ Hamsfork (Lincoln County), 2; Jackson, 5; Jakeys Creek (Fremont County), 1; Kemmerer, 7; Kendall (12 miles north, Sub- lette County), 2; Little Piney Creek (8,000 feet altitude, Sublette County), 1; Merna (Sublette County), 1; Mountainview (Uinta County), 7; Opal (Lincoln County), 2; Pahaska (mouth of Grinnell Creek, Park County), 1; Spring Valley (Uinta County), 2; Stanley (8,000 feet altitude, Sublette County), 1; Valley (Park County), 5; Wind River Mountains (Upper Gros Ventre River, North Fork), 1; Wyoming Peak (10,900 feet altitude, Lincoln County), 1; Yellowstone National Park, 4. CITELLUS BELDINGI (Mereiam) [Synonymy under sub- species] Specific charac- ters.— Slightly small- er than G. r. richard- sonii; hind foot, 41- 47 mm; tail, 55-76; skull length, 41.3- 46.3. Skull similar to that of O. r. ele- gans but relatively longer, and narrower across zygomata, but broader interorbit- ally; zygomata slen- derer ; audital bullae smaller. Coloration of upper parts smoke gray, mixed with pinkish buff, the me- dian dorsal area more or less dark- ened ;with sayal brown or kaiser brown ; under side of tail hazel, upper side mixed with fuscous. Figure 6. — Distribution of the subspecies of Citellus bel- dingl: 1, C. 6. oregonus; 2, C. 6. beldingi. CITELLUS BELDINGI BELDINGI (Merriam) Bei.ding's Ground Squirrel (Pis. 3; 23, E; 28, E) Spermophilus heldingl Merriam, Ann. N. Y. Acad. Sci. 4 : 317, Dec. 28, 1888. [Citellus] beldingi Trouessart, Cat. Mamm., Sup., p. 339, 1904. Type.— Collected at Donner, Placer County, Calif., June 22, 1886, by Cliarles A. Allen; female adult, skin and skull, no. 186467, U. S. Natl. Mus. (formerly no. -VgVrj Merriam collection) (orig. no. 103). Range. — High mountain meadows in the central Sierra Nevada, from Nevada County (Independence Lake) south to the headwaters of Kings River, Fresno County, Calif, (fig. 6). Zonal range: Hud- sonian and Canadian, 6,500-11,800 feet altitude {jide Grinnell). External characters.— '^'wmX^x to G. arrnaius^ but upper parts darker and more reddish, the reddish color on the back usually in a well defined band; tail reddish instead of grayish beneath. *" Cleveland Mus. Nat. Hist. 154070—38 6 g2 NORTH AMERICAN FAUNA [No. 56 Cranial characters. — Skull similar to that of G. richardsonii ele- gans (as defined under specific characters) ; smaller than that of armatus, with relatively broader interorbital region and less widely expanded zygomata. Color. — Front of face sayal brown, shading to hazel on top of head ; sides of face and head mixed fuscous and pinkish buflf ; eye rmg buffy white; nape mixed light buff and hazel; dorsal band (from nape to rump) hazel or kaiser brown (rarely sayal brown) ; sides of body mixed smoke gray and pinkish buff; feet pinkish buff; thighs cinnamon or sayal brown ; tail above mixed hazel and fuscous black ; tail beneath, hazel, bordered with tilleul buff and tipped with fus- cous black ; under parts dull whitish, more or less washed with pink- ish buff. Molt. — In the series examined there are no specimens that show clearly when these ground squirrels change their pelage. Grinnell and Dixon (1918, p. 659) consider that the species has but one molt annually, during July. Measurements. — Average of 12 adults (8 males, 4 females) from type local- ity: Total length, 279.6 (268-296) ; tail vertebrae, 68 (60-75) ; hind foot, 44.3 (42— i7). Skull: Average of 10 adult males from type locality: Greatest length, 45.2 (44-46.3) ; palatilar length, 21.8 (21-22.7) ; zygomatic breadth, 28.8 (27.8- 29.8) ; cranial breadth, 19.5 (18.7-20.2) ; interorbital breadth, 11.2 (10.5-11.9) ; postorbital constriction, 11.7 (10.9-12.7) ; length of nasals, 16.9 (16.1-17.5) ; maxillary tooth row, 9.2 (9-9.4). Average of 10 adult females from tyiae locality: Greatest length, 44.7 (43.2-45.7); palatilar length, 21.8 (21-22.8); zygomatic breadth, 28.9 (28.2-29.6) ; cranial breadth, 19.5 (19.1-19.8) ; inter- orbital breadth, 11.1 (10.7-11.8) ; postorbital constriction, 11.7 (11.1-12.5) ; length of nasals, 16.1 (15.2-17.1) ; maxillary tooth row, 9.5 (9.2-10). Wei£^7il— Average of 10 adult males, 222 g (125.5-285) ; of 10 adult females, 240 (172-^05) (Grinnell and Dixon, 1918, p. 660). Remarks. — Belding's ground squirrel, usually considered to be a distinct species, proves on examination of abundant material to be subspecifically related to C. ieldingi oregonus. It is rather strictly confined to the alpine meadows in the Sierra Nevada of California, and there appears to be a gap of about 25 miles between its range and that of oregonus. Notwithstanding this apparent hiatus be- tween their ranges, there is complete intergradation in characters between the two forms. Specimens examined. — Total number, 236, as follows: California: Alpine City, Bear Valley (Mariposa County), 1; American River (head of South Fork, near Silver Lake), 2; Bishop Creek (Inyo County), 2; Donner (Placer County, including "Summit"), 97; Diamond Valley (Alpine County), 1;^^ Fredericksburg (Alpine County), 1;*^ Hope Valley (Alpine County), 4 ; *V Independence Lake (Nevada County), 13; Johnson Pass (8 miles south of Lake Tahoe), 1: Kaiser Pass (Fresno County), 1; *^ Little Pete Meadow (near head of Middle Fork of Kings River, Fresno County) 1;** Long Valley (Mono County), 2;*^ Mammoth (Mono County), 3 ; McKinneys, Lake Tahoe, 7 ; Mono Lake, 4 ; *^ Mono Pass, 3 ; Mount Dana (Mono County), 3; Mount Conness (Tuolumne County), 1; Mount Tallac (Eldorado County), 2; Owens River (at head), 12; Pine City (Mono County, near Mammoth Pass), 1; Post Corral Meadows (Fresno County), 2;** Sand Meadow (Fresno County), 1;** San Joaquin River (near Mam- moth Pass), 2; Sonora Pass (Alpine County), 2; Tahoe (Placer County), 3; Terrace Meadow (Inyo County), 1;** Tioga Pass (Mono County), 1 ; *" Walker Lake (Mono County), 1 ; *^ Woodf ords (Alpine Coimty), 5;"^ Yosem- ite National Park, 52 (including Lake Tenaya, 7; head of Lyell Canyon, ■^Mus. Vert. Zool. «Wm. T. Shaw Collection. " Cleveland Mus. Nat. Hist. 1938] REVISION OF THE GROUND SQUIRRELS 83 6 ; ^ Merced Lake, 1 ; '' Mount Hoffman, 4 ; ^ Mt. Lyell, 1 ; Mount Unicorn, 1; Porcupine Flat, 2; Tuolumne Meadows, 30);^" Zonoda Meadow (Inyo County), 1." Nevada: Near Bijou, Calif,, 3. CITELLUS BELDINGI OREGONUS (Mereiam) Oregon Ground Squirrel Spermophilus oregonus Merriam, Biol. Soc. Wash. Proc. 12: 69, Mar. 24, 1898. iCitellus} oregonus Trouessart, Cat Mamm., Sup., p. 339, 1904. Type. — Collected in Swan Lake Valley, Klamath Basin, Oreg., June 12, 1897, by Vernon Bailey; female adult, skin and skull, no. 89177, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 6005). Range. — Eastern Oregon, northeastern California, southwestern Idaho, and northern Nevada ; north to Heppner and Elgin, Oreg. ; east to Cassia County, Idaho, and Kuby Valley, Nev.; south to Plumas County, Calif., and Ruby Valley, Nev.; west to Klamath Lake, Oreg., and Goose Nest Mountain, Calif, (fig. 6). Zonal range: Upper Sonoran and Transition. External characters. — Similar to G. h. heldingi, but averaging slightly smaller; upper parts paler and more grayish, usually with- out a distinct reddish tone, and never with a well-defined band of reddish brown; similar to G. richardsonii elegans., but tail shorter and much darker (more reddish) beneath; coloration above usually darker and more reddish (less yellowish or buffy), with less indica- tion of mottling. Compared with G. armatus: Closely similar in size and coloration, but dorsal region paler, the rump and thighs more grayish (less tawny) ; tail reddish rather than grayish below, the bordering hairs more grayish (less buffy). Granial characters. — Skull similar to that of heldingi., but averag- ing slightly smaller and relatively narrower interorbitally. Com- pared with elegant: Skull relatively longer and narrower; zygomata weaker and more contracted anteriorly; auditory meatus shorter. Golor. — Upper parts smolie gray or pale smoke gray, more or less washed on the back with sayal brown, mikado brown, cinnamon, or light pinkish cinnamon; front of face with a patch of pinkish cin- namon or pinkish buff; under parts and sides washed with pinkish buff, the under fur on belly dusky neutral gray; feet pinkish buff; tail above, cinnamon or sayal brown mixed with smoke gray at base and heavily shaded with black on distal half; tail beneath, hazel, bordered with black and edged with pale tilleul buff. Molt. — Only a very few specimens in the large series examined show definite indications of molt; two adults (male and female) from Howard, Oreg., June 16 and 18, apparently are acquiring new pelage, the new hairs coming in irregularly over the whole back. A female from the Ruby Mountains, Nev., June 20, is in a worn gray- ish pelage, with a patch of fresh, reddish pelage coming in on the fore back. Measurements. — Average of 10 adult males from southwestern Oregon and northeastern California (Fort Klamath, Po Valley, Burns, Snsanville, Tule Lake) : Total length, 271.5 (254-300) ; tail vertebrae, G3.8 (55-76) ; hind foot, «Mus. Vert. Zool. "Cleveland Mus. Nat. Hist. **Ten In Mub. Vert. Zool. 84 NORTH AMERICAN FAUNA [No. 56 43 (41-45) ; average of 8 adult females from southern Oregon and northern California: 276; 67; 42.7. Skull: Average of 8 adult males from southwest- ern Oregon and northern California (Fort Klamath, Tule Lake, Susanville, Madeline Divide) : Greatest length, 45 (43.2^-46.2) ; palatilar length, 21.8 (20.5-23) ; zygomatic breadth, 28.9 (28.1-30.1) ; cranial breadth, 20.2 (19.8- 20.6) ; interorbital breadth, 10.1 (9.2-10.7) ; postorbital constriction, 11.7 (10.7-12.3) ; length of nasals, 16.9 (16-18.2) ; maxillary- tooth row, 9.4 (9-10.1) ; average of 8 females from same region : Greatest length, 43.1 (41.3—44) ; palatilar length, 20.8 (19.8-21.5) ; zj'gomatic breadth, 27.8 (24.8-29.8) ; cranial breadth, 19 (18.2-19.5) ; interorbital breadth, 9.5 (9-10) ; postorbital constric- tion, 11.1 (10.4-12) ; length of nasals, 16.1 (15-17) ; maxillary tooth row, 9 (8.6-9.3). Weight. — Two specimens weighed by Vernon Bailey registered 1 pound each ; one of these was recorded as very fat. Grinnell, Dixon, and Linsdale (1930, p. 483) record six individuals as weighing respectively, 212, 223, 230, 250, 260, and 260 g. Grinnell and Dixon (1918, p. 652) give the average weight of 6 adult females as 302 g (267-365.8). ReTnarks. — The Oregon ground squirrel is abundant and widely distributed in the Great Basin. It is closely related to beldingi, and although the ranges of the two, so far as known, are not actually contiguous, 5^et the two forms intergrade completely in both the skin and sijull characters. In fact, there are numerous specimens in both series that are so near like certain individuals of the other race as to be practically indistinguishable. The distinguishing characters, however, are on the average well marked. The present race is known from specimens as far south in California as Prattville, and its presence has been reported at Red Clover and Mohawk, in Plumas County, whereas heldingi is known no farther north than Independ- ence Lake, on the line between Sierra and Nevada Counties, approxi- mately 25 miles southeast of Mohawk. ^Specimens examined, — Total number, 405, as follows: California: Alturas (10 miles southwest, Modoc County), 7;*' Bald Mountain (8 miles south, Shasta County), 13; Bieber (Lassen County), 3; Big Mead- ows (10 miles west, Plumas County), !;■" Bull Meadow (Siskiyou County, northeast of Goose Nest Mountain), 1;^° Bunchgrass Spring (Lassen County), 2; Eagle Lake, 1; Feather River (North Fork, 18 miles east of Warner Creek), 1; Goose Lake, 3; Goose Lake Meadows (near Davis Creek, Modoc County), 2;^' Goose Nest Mountain (Siskiyou County), 1;" Grass Lake (Siskiyou County), 6;*® Hayden Hill (Lassen County), 1; Horse Lake, 7: Lower Klamath Lake, 1; Macdoel (Siskiyou County), 24;*' Madeline Divide, 5; Madeline Plains, 1; Mount Hebron (Siskiyou County), 10; Mount Lassen (probably near Black Butte), 6; Petes Valley (Lassen County), 1; Pine Creek (Lassen County), 1; Pit River (North Fork), 4; Pit River (South Fork), 3;^' Prattville (12 miles northeast), 4; Sugar Hill (Modoc County), 4;" Susan River (Lassen County), 5; Susanville, 6; Termo (Lassen County), 1;^^ Tule Lake, 4; Tuledad Canyon (northeastern corner Lassen County), 1; Warner Mountains, 6; Westwood (15 miles west, Lassen County), 1. Idaho: Elba (Cassia County), l;** Hollister (Twin Falls County), 1 ; *■ Malta (Cassia County), 1;^' Mount Harrison (Cassia County), 1;*" Riddle (15 miles southeast, Owyhee County), 1; Silver City, 8; Sinker Creek (Owyhee County), 25. Nevada: Badger (20 miles northwest of Summit Lake, Humboldt County), 4; Calico Mountain (northeastern Humboldt County), 2; Halleck (Elko County), 1; Massacre Creek (Washoe County), 1;** Mountain City (Elko County), 12; Pine Forest Mountains, 12;" Ruby Moimtains, 1; Ruby Valley, 10. Oregon: Austin (Grant County), 2; Baker (10 miles north), 3;" Barnes (Crook County), 3;" Bear Creek (15 miles northwest of Dayville, Grant County), 1;** Beech Creek (Grant County), 2; Beulah (Malheur County), 13; Bu- ^=Ten in Mus. Vert. Zool. *«Mus. Vert. Zool. ^ Univ. Michigan Mus. Zool. 1938] REVISION OF THE GROUND SQUIRRELS §5 chanan (Harney County), 6; Buck Creek (Crook County), 1; Burns, 2; Camas Prairie, east of Lakeview, 5;*^ Cedar Mountains, 1; Diamond (Har- ney County), 5; Disaster Peak (Malheur County), 1; Drewsey (Harney County), 1; Elgin, 6; Fort Klamath, 23; Harney (10 miles north), 4; Haycreek (Jefferson County), 13; Heppner, 15; Home (Baker County), 10; Howard (Crook County), 4; Jordan Valley (Malheur County), 5; Joseph (Wallowa County), 7; Klamath Falls, 3; Lakeview, 1; Lone Rock (6 miles east, Gilliam County), 1; Lost River, Klamath Basin, 1; Mahog- any Mountain (Malheur County), 3; Malheur County, near McDermitt, Nev., 3; Malheur Lake, 1; Maury Mountains (Crook County), 1; Meacham (10 miles south, Umatilla County), 1; Mount Vernon (Grant County), 2; Mount Warner (=Hart Mountain, Lake County), 2; Narrows (Harney County), 4; Po Valley (Lost River, Klamath County), 1; Prineville, 7; Rattlesnake Creek (at head, Malheur County), 1; Rockville (Malheur County), 1; Shirk (Harney County), 1; Steens Mountains, 13; Swan Lake Valley (Klamath County), 2; Telocaset (Union County), 2; Twickenham (Wheeler County), 2; White Horse Creek (Harney County), 1. CITELLUS PARRYH GROUP CITELLUS COLUMBIANUS (Ord) [Synonymy under subspecies] SpecifiG characters. — Larger than O. richardsonii or C. armatus; hind foot, 48-58 mm ; tail, 80-116 ; skull length, 49.5-57. Skull rela- tively longer than that of richardsonii., the zygomata less widely ex- panded posteriorly; dorsal outline much flatter, the highest point behind the postorbital processes, the rostrum not sharply depressed; interorbital region relatively broad and flat, the supraorbital margins not elevated or thickened; rostrum and nasals longer; upper tooth rows nearly parallel; audital bullae large but not greatly elevated; meatus slightly produced. Color. — Nose and face tawny or hazel; occiput, nape, and sides of neck smoke gray; upper parts cinnamon buff or sayal brown, shaded with fuscous and in winter with smoke gray; hmd legs and feet tawny or hazel; front feet ochraceous buff; tail gray or tawny ; under parts ochraceous buff or tawny. CITELLUS COLUMBIANUS COLUMBIANUS (Ord) Columbian Ground Squirrel (Pis. 4; 24, A; 29, A) Arctomys columUanus Ord, Guthrie's Geography (2nd Amer. ed.), 2:292 (description, p. 303), 1815. Anisonyx hraohiura Raflnesque, Amer. Monthly Mag. 2 : 45, 1817. Arctomys brachyura Hnrlan, Fauna Americana, p. 304, 1825. Arctomys brachyurus Richardson, Fauna Boreali-Americana, p. 151, 1S29. Arctomys parryi var. j8, erythrofiluteia Richardson, Fauna Boreali-Americana, p. 161, 1829 ("Rocky Mountains, near the sources of the Elk River"=Wolf Plain, 30 miles west of Rock Lake, Alberta).** [Spermophihis parryi] var. erythrogluteia Allen, Boston Soc. Nat. Hist. Proc. 16: 292, 1874. Spermophilvs empetra var. erythroglutaeus Allen, Monog. North Amer. Roden- tia, p. 839, 1877 (part). Spermophilns rolnmhiavufi Merriam, North Amer. Fauna 5: 39, 1891. Citellus colnmbianuH Allen, Amer. Mus. Nat. Hist. Bull. 19:536, 1903. Citellus colnmbinnvs albertae Allen, Amer. Mus. Nat. Hist. BuU. 19 : 537, 1903 (Canadian National Park, Alberta). CUellvs (Colobotis) columbianus Preble, North Amer. Fauna 27: 1G4, 1908. *' narnegie Mus. »o See remarks, p. 88. 86 NORTH AMERICAN FAUNA [No. 56 Type. — None designated ; original description based on Lewis and Clark's description of animals taken by them on a camas prairie between the forks of the Clearwater and Kooskooskie Rivers, Idaho, Range.— ^ook^ Mountain region of western Montana, Idaho^ northeastern Washington, southeastern British Columbia, and west- ern Alberta; also the plains of eastern Washington and mountains of east-central Oregon (exclusive of the Blue Mountains) ; north to the headwaters of South Pine Eiver, British Columbia (re- ported by William Fox from this locality and from mountains on east side of the lower Parsnip River) ; south to Craters of the Moon, Butte County, Idaho, and Harney County, Oreg. ; east to Cutbank and Towns- end, Mont.; west to Shuswap and Okana- gan Lake, British Columbia, Oroville, Wash., and Snow Mountain, head of Silver Creek, Harney County, Oreg. (fig. 7). Zonal range: Canadian and Hud- sonian. External charac- ters.— As given under specific characters (p. 85) ; in comparison with C. parryii ple- sms, upper parts not distinctly spotted; sides of neck gray in- stead of buff; hind feet and legs darker (tawny or hazel in- stead of cinnamon buff) ; tail edged with white instead of buff; tail averaging longer and hind feet shorter. Cranial characters. — As given (p. 85) in comparison with 0. rich- ardsonii richardsonii. Compared with plesius: Skull averaging smaller and relatively narrower, the superior outline flatter (less convex); rostrum longer and narrower; supraorbital shelf not ele- vated; palate longer, its posterior border considerably behind plane of last molars; posterior loph of m^ low and sometimes discontinuous. Color. — Summer pelage: Nose and front of face tawny or hazel; Figure 7. — Distribution of the subspecies of Citellus colum- bianus: 1, C. o. columhianus ; 2, G. c. ruficaudus. 1938] REVISION OF THE GROUND SQUIRRELS §7 crown mixed cinnamon buff and smoke gray; occiput, nape, and sides of neck pale smoke gray; eye ring pale buff; ears hair brown on outer surface, buffy or tawny on inner surface; general tone of upper parts cinnamon buff or sayal brown, more or less shaded with the darker color of the under fur, which is fuscous or hair brown; sides washed with grayish or bufl'y v\'hite; under parts cinnamon buff or ochraceous buff; front legs and feet ochraceous buff; hind feet ochraceous tawny, the thighs hazel; tail above, black, rather heavily overlaid with grayish white and sparingly sprinkled vrith cinnamon buff or tawny; tail beneath, mixed fuscous black and grayish white. Winter pelage (March and April) : Similar to the summer pelage but upper parts more heavily sprinkled with grayish. Variation. — Two albinistic juvenile individuals were taken at Pull- man, Wash., May 10, 1906; Svihla (1933, p. 78) reports seeing three albino individuals there in 1933. Molt. — The annual molt occurs in June or July. A female taken at Ketchum, Idaho, June 6, is in a badly worn pelage, with new hair appearing on the forehead; another female (subad.) from Columbia Falls, Mont.. June 27, shows new pelage covering the head and me- dian dorsal region, nearly to the rump ; an adult female from Nelson, British Columbia, July 18, shows a patch of fresh summer pelage on the middle of the back; an adult female from Piegan Pass, Mont., is in a much worn pelage, with new hair appearing on the head and nape; a juvenile from ISilver, Mont., June 26, Avas acquiring a new pelage in patches on the head and back. In the large series examined no evidence has been found that would indicate a molt in the autumn. Measurements. — Average of 12 adults (G males, 6 females) from Idaho: Total length, 349.7 (327-377) ; tall vertebrae, 100.5 (83-116) ; hind foot, 51.2 (48-55). Skull: Average of 10 adult males from Idaho: Greatest length, 51.7 (50-56) ; palatilar length, 25.1 (24-27) ; zygomatic breadth, 31.8 (30.5-33.8) ; cranial breadth, 20.8 (19.6-21.8) ; interorbital breadth, 10.6 (9.0-12) ; post- orbital constriction, 11.3 (10.4-12.5) ; length of nasals, 19.4 (1&-21.4) ; maxil- lary tooth row, 10.9 (10.1-11.8). Average of 7 adult femal(>s from Idaho: Greatest length, 50.7 (49.5-51.9) ; palatilar length, 24.8 (23-26) ; zygomatic l>readth, 32.2 (31.6-33.6) ; cranial breadth. 21 (20.5-21.4) ; interorbital breadth, 11.2 (10.2-12) ; postorbital constriction, 12 (11.4-12.2) ; length of nasals, 18.7 (18-19.4) ; maxillary tooth row, 11 (10.4-11.6).. Weight. — Shaw (1926a, p. 137) gives the weights of two males taken in late July as 589 and 830 g, respectively ; eight males taken from the hibernation den at time of awakening averaged 492 g (43.1-571) ; two males running at large on March 10, after hibernation, weighed respectively, 341 and 375 g. Two females taken when going into hibernation weighed respectivelv, 414 and 500 g (Shaw, 19251, p. 764). Remarks. — The Columbian ground squirrel is quite distinct from any other species and its range apparently does not meet that of C. parryii plesius in British Columbia. The latter reaches its south- ern limit in the vicinity of Tatletuey Lake, and colnmhianus ranges no farther nortli than the mountains lying east of Parsnip River and south of Peace River, tlnis leaving a gap of 160 miles or more un- occupied by ground squirrels of this group. In Montana and south- ern Idaho, this species is apparently extending its range eastward and southward, doubtless attracted from its natural home in the mountain meadows to the cultivated fields in the valleys. The form occupying the Blue Mountains region of Oregon and Wasliington is recognized as a subspecies, but nearly typical colum- hiccnus occurs in the low mountains south of this area and probably 88 NORTH AMERICAN FAUNA [No. 56 in all the surrounding foothills. Two adult specimens from moun- tains 10 miles north of Harney and 3 miles from Ironsides, Oreg., are intermediate, agreeing in color with columbianus and in skull characters with G. c. ruficaudus. Although discovered by Lewis and Clark in their epochal journey across the continent in 1804-6 and described by Ord in 1815, this species was very imperfectly known for many years, and the name columbianus was misapplied to the plateau prairie dog {Gynomys gunnisoni) . Richardson, 1829, named a ground squirrel procured by Drummond in the Canadian Rockies as a variety of the Parry ground squirrel — Arctomys parryi var. fi, erythrogluteia. Allen (1877) adopted Rich- ardson's name, listing under it two specimens from the head of Flathead River and two from Kootenay River — both localities in southeastern British Columbia. Merriam (1891, p. 39), having pro- cured specimens from the vicinity of the type locality of colum- bianus, cleared up the situation, showing that the "burrowing squir- rel" of Lewis and Clark was actually a ground squirrel, and that the names columbianus and erythrogluteia referred to the same species- Allen, however, in 1903, revived the name erythrogluteia and ap- plied it to the form of parryii occurring on the head of Telegraph Creek and Sheslay River, British Columbia, which he recognized as distinct from columbianus and wliich had been named plesius by Osgood in 1900. This assignment of erythrogluteia was made on the assumption that the type locality — Elk River, Rocky Mountains — is in latitude 57° N., as stated by Richardson in the original descrip- tion, and therefore not far from the Telegraph Creek region. This however, was an error, for as Preble has shown (1908, p. 164), the "Elk River" of Richardson is the Athabaska, and its sources are between 52° and 54° N. Richardson's species — erythrogluteia — was based on specimens collected by Thomas Drummond and the type locality is determined by a reading of Drummond's sketch of his journey published in Hooker's Botanical Miscellany (1830, p. 178). On page 212 of this publication he speaks of finding Arctomys parryi abundant "on the mountains near the Wolf's Plain" and states that specimens were "brought home." On page 199 he gives the location of Wolf Plain as "about 30 miles west from Lac-la-Pierre" ( = Rock Lake). Rock Lake is about 25 miles northwest of the lower end of Jasper Lake. This would fix the type locality of erythrogluteia as near the headwaters of Sulphur River, a branch of Smoky River. Specimens of this animal were taken by J. Alden Loring in 1895, on Smoky River, a short distance from this locality, and, as already stated, they prove to be indistinguishable from typical columbianus. Examination of a series from Canadian National Park that formed the basis of Allen's ''^albertae'''' shows their characters to be too slight and inconstant to admit of recognition in nomenclature. The skulls average slightly larger and flatter than those of typical columbianus and the jugal averages broader, but these characters are not constant in the series of 10 skulls examined; the shape of the antorbital foramen varies from triangular to circular. 19381 REVISION OF THE GROUND SQUIRRELS 39 Specimens examhied. — Total number, 351, as follows: Alberta: Banff, 6; [Rocky Mountains] 75 miles southwest of Calgary, 1;" Canadian National Park, 3; '"'■ Crows Nest (Livingstone River), 1; " Crows- nest Pass, 1;'^ Hay River (near head), 1; Henry House (25 miles west), 1 ; Jasper Park, 13 ; '' '' Mount Forgetmenot, 4 : =' Ptarmigan Lake, 3 ; ^' Silver City, 2; °- Smoky Valley (50 miles north of Jasper House), 7; Sulphur River (upper), 2; Waterton Lake Park, 5.°* British Columbia: Barkerville, 1;'' Cascade, G;"" Cranbrook, 9;'' Deer Park, 2 ; '- Fernie. 1 ; ^ Indianpoint Lake, 2 ; ^' Midway, 4 ; ^- Mount Queest, 2 ; "^ Nelson, 12 ; Okanagan, 4 ; " =^ Okanagan Falls, 2 ; "= Shuswap, 4 ; '"^ Shuswap River (headwaters. Gold Range), 1; Spillimachene River, 3.^ Idaho: Bald Mountain Ranger Station (10 miles south of Idaho City), 2; Bitter- root Mountains, 1;'^ Coeur d'Alene, 9; Edna (15 miles northeast of Idaho City), 4; Forney, 2; Fort Sherman (near Coeur d'Alene), 2; Galena (30 miles north of Ketchum), 9; Goodrich (Adams County), 3; Idaho City, 5; Ketchum, 17; Lardo (Valley County), 1; McKinuis (7 miles east, Shoshone County), 1;^ Moscow, 38; Mullan, 5; New Meadows (Adams County), 2; Nez Perce, 2; Packer Meadow (south of Lolo Hot Springs), 4; Seven Devils Mountains, 2; Shafer Butte (Boise County), 6;^ Tamarack (Adams County), 1; Troy, 1;" Warren (Idaho County), 1. Montana: Bass Creek (northwest of Stevensville), 1; Carroll (Deerlodge County), 6; Columbia Falls, 8; Corvallis, 4; Deerlodge County, 1;^^ Flat- head Lake (north end), 2; Flathead River (at International Boundary), 2; Florence, 7: Gibbon Pass (Beaverhead County), 8;^' Hamilton, 3j" Helena, 3; Kalispell, 4; Lolo, 3; McDermott Lake, 3; Nyack (Flathead County), 4: Piegan Pass (Glacier National Park), 1; Prospect Creek (near Thompson Falls), 1; St. Marj', 2;" Silver ( = Saltese, Missoula CoimtyJ, 4; Sula, 1; Thompson Falls, 1; Tobacco Plains (=Gateway, Lincoln County), 1; Willow Creek (7 miles east of Corvallis), 1; Wisdom (20 miles north, Beaverhead County), 4." Oregon: Harney (10 miles north), 4; Ironside (Malheur County), 3;" Straw- berry Mountains, 3. Washington: Calispell Lake (Pend Oreille County), 1; Calispell Peak, 2; Cheney, 2; Colfax, 1; Colville, 16; Gifford (Stevens County), 2; Loon Lake (Stevens County), 6;" Pullman, 4; Spokane, 8; Sullivan Lake (Pend Oreille County), 2; Williams Lake (Spokane County), 1." CITELLUS COLUMBIANUS RUFICAUDUS Howet.l Blue Mountains Gbound Squiekel Citellus columUanus ruficaudiis Howell, Biol. Soc. Wash. Proc. 41 : 212, Dec. 18, 1928. Type. — Collected at Wallowa Lake, Wallowa County, Oreg., April 13, 1919, by George G. Cantwell; female adult, skin and skull, no. 231942, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 1093). Range. — The Blue Mountains region of Oregon and Washington, from Prescott and Dayton, Wash., south to Dixie Butte, Grant Comity, Oreg. ; east to the AVallowa Mountains, Oreg. (fig. 7). Zonal range: Canadian and Hudsonian. External charaGters. — Similar to C. c. columbianus. but upper side of tail tawny (not gray) ; sides of face and usually the throat a deeper shade of tawny ; legs and feet darker ; hind feet longer. Cranial characters. — Skull similar to that of columhianus,^ but larger and relatively broader; zygomata more heavily built, the jugal wider. "^lAmor. JIus. Nat. Hist. "^2 Nat. Mu.s. Canada. C3 Provincial Mus., Victoria, B. C. "" Univ. MichiRan Mus. Zool. ^' iJonalfl R. Dicltey coll. ^ Cleveland Mus. Nat. Hist. "Montana State College. 90 NORTH AMERICAN FAUNA [No. 56 Color. — Summer pelage (May 28) : Forehead and face hazel; sides of nose and throat ochraceous buff or ochraceous tawny; eye ring broad, pinkish buff; occiput cinnamon buff, more or less mixed with smoke gray and fuscous; sides of neck (beneath eyes) and an in- distinct band across nape, smoke gray; dorsum cinnamon buff grizzled with fuscous; sides smoke gray, mixed w^ith fuscous; front legs and feet tawny or ochraceous tawny; hind feet deep tawny, the thighs russet ; tail above, deep tawny, the hairs banded subterminally with fuscous black and cinnamon buff ; tail beneath, mixed tawny and smoke gray; under parts clay color or cimiamon buff, shading to ochraceous tawny on throat. Winter pelage (April 13) : Similar to the summer pelage, but upper parts pale smoke gray, mixed with pinkish buff' and grizzled with fuscous; feet slightly paler tawny. Molt. — A female specimen from the Blue Mountains, Wash. (3,000 feet altitude), June 16, is in badly worn condition, with new hair appearing on the head and nape. Measurements. — ^Average of 10 adults (8 males, 2 females) from the Wallowa Mountains, Enterprise. Elgin, and Bourne, Oreg. : Total length, 369.6 (340-410) ; tail vertebrae, 100.7 (80-115); hind foot, 54.2 (51-58). ^kull: Average of 8 males (ad. and subad.) from same localities: Greatest length, 54.2 (51.5-57) ; palatilar length, 26.6 (24..5-28) ; zygomatic breadth, 34.1 (33.2-.35.6) ; cranial breadth, 21.9 (21.5-22.4) ; interorbital breadth, 12.4 (11.1-14.3) ; postorbital constriction, 11.9 (10.5-12.6) ; length of nasals, 19.8 (18.8-20.3) ; maxillary tooth ro-w, 11.4 (10.5-12.4). Average of 4 females from same region: Greatest length. 52.9 (50.7-54.7) ; palatilar length, 25.7 (24.5-27.5) ; zygomatic breadth, 33.3 (31.2-34.6) : cranial breadth, 21.3 (20.4-21.7) ; interorbital breadth, 12.5 (11.5- 13.2) ; postorbital constriction, 12.1 (11.9-12.3) ; length of nasals, 19.3 (18.7- 19.7) ; maxillary tooth row, 11.3 (11-11.8). Remarhs. — This race is restricted to the Blue Mountains region of northeastern Oregon and southeastern Washington; it intergrades with coluTnbianus in the Strawberry Mountains and on the southern slopes of the Burnt River Mountains, Oreg. Specimens examined. — Total number, 69, as follows : Oregon: Anthony (6 miles southwest of Cornucopia), 16;"^ Austin (Grant County), 1; Bourne (Baker County), 3; Cornucopia (Baker County), 7; Dixie Butte (Grant County), 6; Elgin, 5; Enterprise, 2; Joseph, 1 :™ Meacham, 4 ; "Wallowa Lake, 7. Washington: Anatone (Asotin County), 2; Blue Mountains (21 miles south- east of Dayton), 4; Dayton, 4;'' Prescott, 7.**'" CITELLUS PARRTII (Richardson) [Synonymy under subspecies] Specific characters. — Size medium to large; hind foot, 50-68 mm; tail, 77-138 ; skull length, 50.7-65.7. Skull heavily built and angular, its superior outline convex, highest at plane of postorbital processes ; the rostrum and brain case moderately depressed; zygomata broad and heavy, widely spreading and strongly twisted from the vertical plane ; postorbital processes heavy, depressed, directed slightly back- wards; supraorbital shelf thickened and elevated; nasals broad, ending about even with premaxillae; antorbital canal large, orbic- ular, with a pronounced process at its anterior opening; audital bullae broad, moderately inflated, the meatus tube moderately pro- duced; molariform teeth heavy, the anterior upper premolar {p^) ssAmer. Mus. Nat. Hist. "^ Univ. Michigan Mus. Zool. ««Mus. Vert. Zool. 1938] REVISION OF THE GROUND SQUIRRELS 91 one-third to nearly one-half of p*; i)osterior loph on m^ well de- veloped (but lower than anterior loph) and continuous (not broken by a sulcus in middle) ; incisors relatively slender and projecting forward. Color. — Head tawny or cinnamon; rest of upper parts red- dish brown, cinnamon, or fuscous, more or less abundantly flecked with rather large whitish spots; under parts ochraceous tawny to cinnamon buff in summer pelage, ochraceous buff or grayish white in winter; sides of head and body buff or tawny in summer, becoming smoke gray in winter; feet and legs tawny, ochraceous buff, or cin- namon; tail above, ochraceous tawny, cinnamon, or cinnamon buff, more or less mixed with fuscous black ; tail beneath, russet or tawny. % ^S^'^^s "X // C / / ^^'^ M X ^ »- >s^ L^^ $^K '^^~\ V3«!.©P_^ s'^^^ ^^^s. '•^c^^^o^^ ^^f3 w\\ 1 1 w I i r Figure 8. — Distribution of the species and subspecies of the Citellus parryii group : 1, C. p. parryii; 2, C. p. banoice7inis ; 3, C. /'. plesiusj 4, C. p. abltisus ; 5, C. p. nebulicola; 6, G. kodiacenais ; 7, O. oagoodi; 8, C. p. lyrattis. CITELLUS PARRYII PARRYII (Richakdson) Fabry's Ground Squiebel Arctomys parryii Richardson, Appendix to Parry's Second Voyage, p. 316, 1825 (1827). Spermophilus parryii Lesson, Manuel de Manim., p. 244, 1827. Arctomys {Spermophilus) parry i Richardson, Fauna Boreali-Amer. 1: 158, 1829. Arctomys parry i var. phaeognatha Richardson, Fauna Boreali-Amer. 1 : 161, 1829 (Hudson Bay). A[rctomys] kennicottii Ross, Canad. Nat. & Geol. G: 434, 1861 (Fort Good Hope, Mackenzie). Spermophilus empetra Allen, Monog. North Amer. Rodentia, p. 839, 1877 (not Mus empetra Pallas). Spermophilus parryi Preble, North Amer. Fauna 22 : 46, 1902. Citellus parryii Miller and Rehn, Boston Soe. Nat. Hist. Proc. 31 : 75, 1903. Citellus (Colobotis) parryi kennicotti Preble, North Amer. Fauna 27: 162, 1908. Citellus (Cololotis) parryi Preble, in Seton, The Arctic Prairies, app. F., p. 342 1911. Citellus parryi kennicottii, Hall, Calif. Univ. Pubs., Zool. 30 : 423, 1929. Type. — None designated; description based on specimens collected at Five Hawser Bay, Lyon Inlet, Melville Peninsula, Hudson Bay, Canada. Range. — Barren Grounds of northern Canada from Melville Penin- sula and western shores of Hudson Bay west to northwestern Yukon 92 ' NORTH AMERICAN FAUNA [No. 56 and northeastern Alaska ; south to Rampart House on Alaska- Yukon boundary, Artillery Lake, Mackenzie, and a point about 25 miles south of Cape Eskimo, Hudson Bay ^^ (fig. 8). Zonal range: Arctic. External characteTS. — Size large; entire head (in summer) tawny or russet; upper parts brownish, more or less mixed with gray and flecked with large, irregular, whitish spots ; tail russet beneath, edged with cinnam^on; under parts tawny; winter pelage much paler and more whitish, the under parts ochraceous buff or grayish white. Cranial characters. — As given under specific characters (p. 90) ; skull large, equaling that of G. osgoodi; much larger than that of G. p. plesius; temporal ridges uniting in adults to form a prominent sagittal crest. Color. — Summer pelage (Hudson Bay, 25 miles south of Cape Eskimo, August) : Top of head (nose to occiput) russet or tawny; sides of nose and face cinnamon buff or ochraceous buff; eye ring (often indistinct) pinkish buff or cartridge buff; sides of neck tawny, shaded with fuscous black; dorsum russet or bister, abun- dantly flecked with rather large, irregular spots of creamy white or buffy white; front and hind legs tawny or ochraceous tawny, the feet ochraceous buff; under parts ochraceous tawny, becoming cin- namon buff on the throat; tail above, blackish, shaded on proximal half with ochraceous tawny or hair brown and sparingly edged with ochraceous tawny or avellaneous; tail beneath, russet, widely bor- dered at tip with blackish. Winter pelage (Dolphin and Union Strait, Arctic coast. May) : General tone of upper parts pale smoke gray, sparingly sprinkled with black hairs and shaded with sayal brown in the middle of the back ; top of head and face cinnamon or pinkish cinnamon; under parts pinkish buff or ochraceous buff; tail above, smoke gray, mixed with cinnamon buff, the tip blackish; legs and feet pinkish buff, pinkish cinnamon, or ochraceous buff. Variation. — Several young specimens from Artillery Lake, Mackenzie (U. S. Natl. Mus. nos. 180894, 180895, Aug. ^6), differ from Hudso]! Bay specimens taken at the same season in having the back of a grayish tone, produced by a mixture of fuscous and grayish white. An adult (no. 180922) from the same locality, but without date, is of the normal brownish color. A series of subadult specimens from Clinton Golden Lake and Thelon River, Mackenzie, taken in early August, are in worn pelage distinctly paler and more grayish tlian the August specimens from the coast of Hudson Bay. An adult from Gollinson Point, on the north coast of Alaska (Sept. 30) has tlie under parts grayish white, very faintly washed with pale pinkish buff; others from the same section at the same season have the under parts partly white and partly ochraceous buff. Several summer specimens from Cape FuUerton, Hudson Bay, have the head and sides of neck heavily washed with bay or chestnut and others from the northeast coast of Alaska have a less intense 81 A specimen in the National Museum of Canada, collected by Owen O'Sullivan and labeled as from "Lat. 53° N., Long. 83° W." indicates a southward extension of the ani- mal's range to a point on the west side of James Bay ; Dr. R. M. Anderson has kindly looked up the records of O'SuUivan's trip (Canada Geol. Survey Summary Kept., 190S, no. 1072, 1909, p. 93) and he finds no reason to doubt that the specimen was taken at the point indicated by the label. In view of the fact, however, that other explorers have failed to find any evidence of the occurrence of this species at either Fort Churchill or York Factory, the record from James Bay is most surprising, and suggests the possibility of error. 1938] REVISION OF THE GROUND SQUIRRELS 93 wash on the head and a broad streak of chestnut on the middle of the belly. Molt. — The spring molt takes place chiefly in June but the process is clearly shown by only a few of the specimens examined. An adult male from Firth River, Alaska- Yukon boundary, June 24, 1912, is in badly worn winter pelage, with the new summer pelage showing in patches on the nape and back ; another adult male from U Creek, Alaska, June 27, shows new pelage covering the head, fore legs and portions of the belly. An adult female from Old Fort Good JHope, June 27, is acquiring a fresh pelage of a grayish tone on the upper parts, the under parts apparently in complete summer pelage, but the tail hairs not fully renewed. An adult female from Clinton Colden Lake, Mackenzie, August 2, is in greatly worn pelage, with new hair of a grayish tone coming in on the shoulders, and patches of new buffy hair on the under parts. The fall molt occurs in September or October, and as usual in this genus, the change is obscurely indicated. Two specimens from Collinson Point, Alaska, taken September 22 and 24, 1913, show the winter pelage cover- ing the head, shoulders, fore back, and most of the under parts, the moderately worn suimner pelage still remaining on the hinder back and on the middle of the belly. Measurements. — Average of 8 adult males from the Arctic coast of Mack- enzie (Corouatiou Gulf to Franklin Bay) : Total length, 443 (420-495) ; tail vertebrae, 124 (115-13G) ; hind foot, C5.6 (G3-68). Average of 5 adult females from same localities: Total length, 414 (890-430) ; tail vertebrae, 122.6 (9S- 13S) ; hind foot, 50.2 (57-61). Average of 9 adult males from Aylmer and Clinton Colden Lakes and near Cape Eskimo, Mackenzie : Total length, 4U0 (380-430); tail vertebrae, 125 (115-140); hind foot, 63.6 (60-66). Skull: Average of 6 adult males from west coast of Hudson Bay (Cape Fullertou and Cape Eskimo) and Aylmer and Clinton Colden Lakes, Mackenzie : Greatest length, 60.9 (60-62.2) ; palatilar length, 31.2 (30.3-32.5) ; zygomatic breadth, 402 (39.3-42) ; cranial breadth, 24.7 (23.5-25.5) ; interorbital breadth, 13.4 (12.9-13.8) ; postorbital constriction, 13.4 (12.7-14.1) ; length of nasals, 23.6 (21.0-25.1); maxillary tooth row, 13.6 (13.2-14.1). Average of 4 old adult males from Dolphin and Union Strait, Arctic coast : Greatest length, 64.3 (63.3-65.7) ; palatilar length, 33.2 (33-33.5) ; zygomatic breadth, 42.8 (40.6- 44.1) ; cranial breadth, 25.4 (24.7-26.4) ; interorbital breadth, 14.9 (14.3-15.6) ; postorbital constriction, 12.9 (12.4-13.3) ; length of nasals, 25 (23.7-25.9) ; maxillary tooth row, 14.1 (13.7-14.3). Average of 6 adult females from west coast of Hudson Bay and interior Mackenzie: Greatest length, 57.5 (55.4-59.5) ; palatilar length, 29.6 (20-30.5, 3 specimens); zygomatic breadth, 37.6 (35.8- 39.4) ; cranial breadth, 23.5 (22.8-24.2) ; interorbital breadth, 12.9 (12.5-13.4) ; postorbital constriction, 134 (11.7-14.3); length of nasals, 21.5 (20-22.9); maxillary tooth row, 13.3 (12.4-13.7). Average of 4 old adult females from Arctic coast (Dolphin and Union Strait and Coronation Gulf) ; Grealest length, 61.2 (60.7-62.1); palatilar length, 31.9 (.31.5-32); zygomatic breadth, 40.9 (40.5-41.5) ; cranial breadth, 24.5 (24.2-24.9) ; interorbital breadth, 13.6 (12.0-14.4) ; postorbital constriction, 13.1 (12.2-13.7) ; length of nasals, 23.4 (23.2-24) ; maxillary tooth row, 13.8 (13.4-14.2). Weight.— K male taken at Collinson Point, Alaska, September 9, weighed 2 pounds, 4 ounces ; another male from the same locality, September 7, weighed 2 pounds, 8 ounces; and a female taken there October 2, weighed 1 pound, 9 ounces. Remarks. — Although described more than a hundred years ago, this large ground squirrel, until recently, has been imperfectly known and poorly represented in collections. Even now, although a series of over 100 specimens has been brought together, there is a lack of material in unworn summer pelage, which fact makes it difficult to describe the pelage variations. The species exhibits a very con- 94 NORTH AMERICAN FAUNA [No. 56 siderable amount of both individual and seasonal variation and from only a few localities are there unworn specimens illustrating both the summer and the winter pelages. Specimens in fresh winter pelage are lacking from Hudson Bay and the entire region east of Coronation Gulf. A series from Cape Fullerton, Hudson Bay — some 225 miles southwest of the type locality — undoubtedly represents the typical form. These are without date of capture (excepting one marked October) but apparently were taken in late summer (August or September) . Most of them show considerable wear. Two adults in slightly worn summer pelage and two full grown young of the year in unworn pelage taken near Cape Eskimo, Hudson Bay, Aug- ust 10 and 11, 1900, are slightly darker above than the average of the Cape Fullerton specimens, the back less strongly flecked with whitish spots. These Cape Eskimo specimens, however, are considered typi- cal and have been used in making comparisons; they may be very closely matched in a large series taken in July and August on Firth Eiver, northwestern Yukon, about 45 miles from the Arctic coast. The skulls of these Yukon specimens average slightly smaller than the series from Hudson Bay but are essentially like them in their characters. Variation in size of skull is extreme in this species. Eight very old specimens (four males, four females) in a series from the vicinity of Coronation Gulf, Arctic coast, are decidedly larger than any others examined. Probably this excessive size is due to the age of the animals, and a larger series, including some subadults, would doubt- less show a smaller average. Nine adult males of a series from Firth River, on the Alaska- Yukon boundary (which, as stated above, agree in color with parity ii from Hudson Bay) average slightly smaller than either the Hudson Bay series or those from the Alaska coast. The disposition of the name kennicotfii, proposed by Ross in 1861 is made difficult by the lack of comparable material from the type locality, which, as shown by Preble (1908, p. 162), is "the lower Mackenzie region", in the vicinity of Old Fort Good Hope and Anderson River. Unfortunately, there are available only three summer specimens from this section, one from Old Fort Good Hope, taken June 27, one from Lockhart River, without date, and one from Anderson River, August 1. The Anderson River specimen is an immature individual m a much worn pelage, but is clearly referable to parryii, the under parts being of the same tawny color ; the Lock- hart River specimen is in a worn (summer?) pelage, with very indis- tinct spotting; the under parts and sides are ochraceous buff, con- siderably paler than in typical parryii; the Fort Good Hope speci- men was apparently acquiring summer pelage; it is paler on the head, tail, sides, and under parts than typical pan^yii; the upper parts are of a uniform brownish gray tone, practically without spotting; possibly this individual, which in size and cranial char- acters agrees with parryii, represents approach to the subspecies plesius^ which occupies the mountainous regions west of the Mac- kenzie Valley; the same may be said of two specimens from Fort McPherson, which are slightly paler than parinjii and have smaller skulls. Preble (1908, p. 162) has set uj) ^''ItennicottiP as a subspecies of parryii^ considermg it to be identical with C. p. 'bai^roicensis, but the recent acquisition of a lai'ge series of the latter form from Point 1938] REVISION OF THE GROUND SQUIRRELS 95 Hope, Alaska, shows it to be decidedly paler than typical 'parryii and paler even than the specimens representing "kennicoitii." In con- sideration also of the occurrence of practically typical parryii in the mountains along the Alaska- Yukon boundary, lying to the west- ward of the Mackenzie Valley, it seems probable that when a larger series from the type region of '■^kennicottii'^ is made available, they will be shown to be referable to parryii. The almost complete absence of specimens in summer pelage from the Arctic coast of Mackenzie and Alaska makes it difficult to deter- mine with certainty the western limits of the present form on that coast. However, since the series in summer pelage from Firth River, Yukon, some 45 miles back from the coast, is clearly referable to parryii, it seems reasonable to consider that the specimens in winter pelage from the northeast coast of Alaska, as far west as CoUinson Point, are of the same race. No specimens are available between Collinson Point and Point Barrow. /Specimens examined. — Total number, 205, as follows : Alaska: Collinson Point, 11;"^ Hula Hula River, 8;"^°^ International Boundary, 80 miles north of Porcupine River, 1 ; Okpilak River (west of Barter Island), 4;^ Porcupine River (12 miles below Coleen River and near Salmon Trout River), 4; Sadlerochit River, 2."^ Northwest Territories [Mackenzie]: Anderson River, 2; Artillery Lake, 16 (3 skins with skulls, 13 skulls only) ;" Aylmer Lake, 9*^ (skulls) ; Bernard Harbor (Dolphin and Union Strait), 25;*' Clinton Golden Lake, 10; Cop- permine River (mouth), 3;"' Cape Eskimo, 3;^ Cape Fullerton, 9;*" Coro- nation Gulf, 6 ; ^'^ ** Deas Thompson Point, 1 ; *' Dease Bay, Great Bear Lake, 2;" Fort Anderson, 7 (1 skin, 6 skulls only) ; Fort Good Hope, 2; Fort McPherson, 2; Hanbury and Thelon Rivers (junction), 5;" Hudson Bay (25 miles south of Cape Eskimo), 4; Kasha Lake, 2; Langton Bay (arm of Franklin Bay), S;*^ Lockhart River, 2; "Mackenzie" (no labels), 7 ; '' Mackenzie River Delta, 3 ; ^' Marble Island, 1 ; Old Fort Good Hope, 4. Yukon: Firth River (on 141st. meridian), 15: Joe River (Firth River), 17; Old Crow River (mouth, and 50 miles above Timber Creek), 11; Rampart House, 2; U Creek (90 miles north of Rampart House), 2. CITELLUS PARRYII BARROWENSIS (Meemam) Babeow Ground Sqtjibbel Bpermophilus harrowcnsis Merriam, Wash. Acad. Sci. Proc. 2 : 19, Mar. 14, 1900. Spermophilus beringensis Merriam, Wash. Acad. Sci. Proc. 2: 20, 1900 (Cape Lisburne, Alaska). Type. — Collected at Point Barrow, Alaska, May 30, 1883, by Lt. P. H. Ray ; male adult, skin and skull ; no. if§4i, U. S. Natl. Mus. (orig. no. 1428). Range. — Arctic coast of Alaska from Point Hope eastward at least to Point Barrow; limits of range not known (fig. 8). Zonal range: Arctic. External characters. — Similar to C. p. parryii, but coloration paler, both above and below; top and sides of head, sides of neck, and thighs paler (less reddish) ; similar in color to C. p. ablusus, but upper parts averaging paler (less brownish) ; sides of body more tawny (less grayish), and under parts slightly darker. •"Natl. Mu.s. Canada. •^Amer. Mus. Nat. Hist. "* Twelve in Amer. Mus. Nat. Hist. 95 NORTH AMERICAN FAUNA [No. 56 Cranial characters. — Skull essentially like that of parryii. Color. — Summer pelage (August) : Top of head (nose to occiput) tawny or russet; sides of face cinnamon buff; sides of neck ochra- ceous tawny ; upper parts sayal brown or mikado brown, abundantly and coarsely flecked with whitish or warm buff spots ; nape and fore- back washed with grayish white ; legs cinnamon ,*■ feet cinnamon buff ; tail tawny or mikado brown, more or less mixed above with black, tip wholly black; under parts cinnamon or cinnamon buff. Winter pelage (October-May) : Coloration of upper parts and sides more grayish than in summer ; sides of nose pinkish buff ; feet paler than in summer, sometimes pinkish buff; under parts cinnamon buff or pinkish buff. Molt. — The spring molt is not shown by any of the specimens ex- amined, but probably it occurs in June, as in the other races. Measurements. — Average of 11 adult males from Point Hope, Alaska : Total length, 411.6 (383-440) ; tail vertebrae, 118.6 (107-142) ; liind foot, 65 (61-68) ; ear from notch (dry), 7.6 (6-9). Average of 10 adult females from Point Hope: Total length, 390.2 (368-^20); tail vertebrae, 113.2 (101-127); hind foot, 61 (59^65) ; ear from notch (dry), 6.7 (6^7). Skull: Average of 12 adult males (Point Barrow, 7; Point Hope, 5): Greatest length. 60.9 (58-62.9); palatilar length. 32 (30.8-33) ; zygomatic breadth, 40.4 (38.1-42.2) ; cranial breadth, 24.4 (24.2-25.1) ; iuterorbital breadth, 13 (12.1-13.5) ; postorbital con- striction, 13.9 (13-15.5) ; length of nasals, 23 (21.3-25.4) ; maxillary tooth row, 33.9 (13.2-15). Average of 6 adult females (Point Barrow, 2; Point Hope, 4) : Greatest length, 59.1 (57.8-60.8) ; palatilar length, 30.9 (30-31.8) ; zygomatic breadth, 39.7 (37.9-41.2) ; cranial breadth, 23.2 (22.4-24.1) ; Interorbital breadth, 12.9 (12.2-14.6) ; postorbital constriction, 12.7 (12-14.4) ; length of nasals, 21.9 (20.9^23.1) ; maxillary tooth row, 13.4 (13-13.9). Remarks. — The ground squirrels inhabiting the northwest coast of Alaska are distinctly paler than typical parryii from Hudson Bay. The series of eight summer skins from Point Barrow agrees essen- tially with a large series from Point Hope, recently collected by R. M. Gilmore for the Museum of Vertebrate Zoology; hence the name C. p. heHngensis.^ based originally on two skins without skulls from Cape Lisburne, is placed in the synonymy of C. p. harrotoensis., the latter name having page priority. The subspecies ranges east- ward on the coast at least to Point Barrow and possibly farther, but no specimens have been seen from points between Point Barrow and Collinson Point. The majority of the specimens available from the Arctic coast of northeastern Alaska and Mackenzie are in winter pelage, in which pelage the characters are less pronounced; a good series in summer pelage is needed to determine with certainty the limits of range of the two races, parryii and harroioensis. Specimens examined.- — Total number, 69, as follows: Alaska: Cape Lisburne, 4 (2 skins, 2 separate skulls) ; Cape Thompson, 1 ;^' Point Barrow, 31 (15 skins; 16 extra skulls) ; Point Hope, 30"; Wain- wright, 2 " ; Wainwright Inlet, 1. «= Mus. Vert. Zool. «« Twenty-eight in Mus. Vert. Zool. «^ Colorado Mus. Nat. Hist. 1938] REVISION OF THE GROUND SQUIRRELS 97 CITELLUS PARRYII PLESIUS (Osgood) Yukon Ground Sqtjibbel (Pis. 24, D; 29, D) Spermophiltis empetra plesius Osgood, North Amer. Fauna 19: 29, Oct. 6, 1900. Ciitellusl plesius Osgood, Biol. Soc. Wash. Proc. 16: 25, 1903. Citellus erythrogluteius Allen, Amer. Mus. Nat. Hist. Bull. 19: 534, 1903 (not Arctomys parryi var. j8 erythrogluteia Richardson). Type. — Collected at Bennett City, head of Lake Bennett, British Columbia, June 19, 1899, by W. H. Osgood; female adult, skin and skull, no. 98931, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 465), Rmige. — Northwestern British Columbia, greater part of Yukon (except extreme northern part) and mountainous parts of Mackenzie (west of the Mackenzie River) ; north to the Ogilvie Range (head of Coal Creek), Yukon; east to Fort Liard and the Nahanni Hills, Mackenzie; south to vicinity of Tatletuey Lake, British Cohunbia; west to Glacier, British Columbia, and Delta River (Ober Creek), Alaska (fig. 8). Zonal range: Hudsonian. External characters. — Similar to G. p. 'parryii^ but decidedly smaller; coloration much paler and more grayish (less tawny) above; sides, under parts, and feet paler ; dorsal spots smaller. Cranial characters. — Skull similar to that of parryii^ but much smaller; rostrum and nasals shorter; zygomata less widely expanded; frontal shield less elevated; temporal ridges less distinctly lyrate than in C. p. lyratus and C. kodiacensis, but not united posteriorly in a prominent crest as in C p. ahlusus. Teeth similar; posterior loph on m^ usually continuous and well developed. Color. — Summer pelage: Head and front of face tawny or sayal brown ; sides of nose clay color or cinnamon buff ; sides of head and neck ochraceous tawny or cinnamon buff, mixed with fuscous; gen- eral tone of upper parts buffy gray, caused by a mixture of fuscous, pinkish buff, and grayish white (the hairs being fuscous subter- minally and tipped with whitish or pinkish buff) ; back moderately sprinkled with grayish white, squarish spots (sometimes indistinct or nearly obsolete) ; sides and under parts ochraceous tawny or cin- namon buff; feet cinnamon, cinnamon buff, or clay color; tail above mixed cinnamon and fuscous, becoming fuscous black on distal half, and edged with pinkish buff; tail beneath, tawny or pale russet, the tip fuscous black. Winter pelage (Sept. 19) : Upper parts and sides pale smoke gray shaded with fuscous and washed in middle of back with cinnamon buff; under parts grayish white, thinly washed with pinkish buff; otherwise as in summer. Molt. — The spring molt takes place in late June; two specimens from Bennett, British Columbia, June 18 and 22, are in badly worn winter pelage, with new pelage covering the head, nape, and most of the under parts. Specimens showing the fall molt are not avail- able, but one from Bennett taken September 19 is apparently in full winter pelage. Measurements. — Average of 10 adult males from type locality : Total length, 339.2 (320-363) ; tail vertebrae, 95.5 (85-105) ; hind foot, 54 (50-57). Average of 8 adult females from Bennett, British Columbia, and head of Coal Creek, Yukon: Total length, 329 (300-352) ; tail vertebrae, 90.4 (85-102) ; hind foot, 52.9 (52-54). SlcuU: Average of 10 adult males from type locality: Greatest 154970—38 7 gg ' NORTH AMERICAN FAUNA [No. 56 length, 53.5 (51.5-56.4) ; palatilar length, 26.2 (25-28) ; zygomatic breadth, 34.6 (33.5-35.5) ; cranial breadth, 22.5 (21.4-23.3) ; interorbital breadth, 11.2 (10.2-12.2) ; postorbital constriction, 13.2 (12.6-13.7) ; length of nasals, 19 (17.7-20.7) ; maxillary tooth row, 12 (11.4-12.4). Average of 10 adult females from type locality: Greatest length, 52 (50.7-53.3) ; palatilar length, 25.5 (25- 26) ; zygomatic breadth, 33.5 (32.2-^4.9) ; cranial breadth, 21.6 (21.1-22.1) ; interorbital breadth, 10.5 (10-11.4) ; postorbital constriction, 12.6 (11.9^13.1) ; length of nasals, 18.7 (18.1-19.8) ; maxillary tooth row, li;7 (11.1-12.3). Weight. — An adult female (Chitina River, Alaska) weighed slightly over one pound (no embryos). Remarks. — The Yukon ground squirrel is distinguishable from parryii and G. osgoodi by its smaller size and paler coloration. It occupies the greater part of the Province of Yukon (except the por- tion north of the Porcupine River) as well as parts of Mackenzie and British Columbia, and ranges westward into Alaska, where it merges into the subspecies dblusus. Southward it does not reach the range of G. columbianus. Specimens from the headwaters of Telegraph Creek and Sheslay River, northern British Columbia, were assigned by J. A. Allen (1903a, p. 534) to Gitellus erythrogluteius (Richardson) on the as- sumption that its type locality — "head of Elk River, Rocky Momi- tains" — is in latitude 57°, as indicated by Richardson. As shown, however, on page 88, the Elk River of Richardson is the Athabaska, whereas the type locality of erythrogluteia is actually near the head- waters of Sulphur River, Alberta. Specimens examined. — Total number, 158, as follows : Alaska: Chitina River Glacier, 4;** Ober Creek (Jarvis Creek, Delta River region), 2; Tanana Crossing, 1; Tanana Hills, 2; White Pass, 5. British Columbia: Bennett, 38; Chapa-atan River (Stikine River, near head), 8; Cassiar Mountains (near Dease Lake), 2; Ispatseezeh River (Stikine River, near head), 3; Klappan River Valley (near head), 1; Little Klappan River (headwaters), 1; McDame Creek (Dease River), 3; McKee Creek, Atlin District, 1;°* Rapid River (Dease River), 1; Sheep Mountain (Dease River), 2; Sheslay River (timber line, 4,000 feet altitude), 1; Tatletuey Lake, 1; Telegraph Creek (near head), 6; Wilson Creek, Atlin District, 5.*" Northwest Territories [Mackenzie] : Fort Liard, 1 ;™ Fort Norman (mountains west), 1; Fort Simpson [probably from Nahanni Hills], 1;" Mackenzie Mountains, 2." Yukon: Coal Creek (near head), 18; Donjek River, 2; Livingston, 1;" Pelly Lake, 1; Pelly River (Lapie River), 6; Tantalus, 1;** Teslin Lake (and vicinity), 25;°' Yukon River, 17 (Caribou Crossing, 6; Fifty-mile River, 1; Lake Lebarge, 2; Lake Marsh, 6; Miles Canyon, 1 ; Rink Rapids, 1). CITELLUS PARRYII ABLUSUS Osgood Aleutian Geound Squirrel Gitellus plesius ablusus Osgood, Biol. Soc. Wash. Proc. 16: 25, Mar. 19, 1903. Gitellus stonei Allen, Amer. Mus. Nat. Hist. Bull. 19 : 537, 1903 ( Stevana Flats, near Port Moller, Alaska Peninsula (not Wraugell), Alaska). (Allen, op. cit. p. XVII). Type. — Collected at Nushagak, Alaska, September 16, 1902, by W. H. Osgood and A. G. Maddren; male adult, skin and skull, no. 119815, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 2043). «8Natl. Mus. Canada. ** Provincial Mus., Victoria, B. C. ''"Univ. of Michigan Mus. Zool. ■^ Field Mus. Nat. Hist. ^2 Amer. Mus. Nat. Hist. 1938] REVISION OF THE GROUND SQUIRRELS QQ Range.— Alaska, mainly south of the Yukon Valley ; north on the coast to Eschscholtz Bay; west on the Alaska Peninsula to its tip; south to base of the Kenai Peninsula ; east to headwaters of Tanana River; introduced on Unalaska, Uninak, and Kavalga Islands (fig. 8). Zonal range: Hudsonian and Arctic. External characters. — Similar in color to 0. p. plesius but upper parts (in summer) more brownish (less grayish) ; dorsal spotting less distinct and spots smaller; under parts averaging paler; tail usually more blackish, the under surface a slightly darker shade of russet; skull larger and relatively narrower. Compared with C. p. parry ii: Size much smaller; dorsal spots smaller; coloration paler, especially on the under parts, sides of neck legs, and mider surface of tail. Compared with G. p. harrowensis : Size smaller; coloration of upper parts darker (more brownish) ; sides paler (less tawny) ; under parts averaging j)aler. Cranial characters. — Skull larger than that of plesius, with rela- tively narrower brain case ; rostrum and nasals longer ; audital bullae larger — both longer and broader — but rather flat; temporal ridges less distinctly lyrate in shape than in G. p. lyratus and G. kodi- accTisis, uniting posteriorly to form a slight crest; skull decidedly smaller than that of haj-^rowensh or pai^yii. Golor. — Summer pelage: Top of head and face russet or tawny; sides of head pinkish buff or cinnamon buff, shaded with fuscous; front legs and sides of neck tawny; upper parts walnut brown, washed on neck and shoulders with pale buff, and abundantly flecked with irregular, buffy white spots ; fore and hind feet clay color ; tail above, mixed cinnamon buff and fuscous black, becoming solid blackish on distal fourth ; tail beneath, russet or tawny ; under parts clay color or cinnamon buff. Worn lointer pelage: General tone of upper parts snuff brown, washed on neck and shoulders with pale smoke gray; sides of head and neck smoke gray; sides of body pale buff mixed with white; under parts gi-ayish white, faintly washed with pinkish buff; otherwise as in summer. Molt. — The beginning of the spring molt is shown by an adult male specimen taken June 16 at Lake Aleknagik, Alaska ; new hair is ap- pearing on the head, shoulders, and fore legs, the rest of the body being in worn winter pelage. Measurements. — Average of 8 adult males from Nushagak and Swau Lake, Alaska: Total length, 874.5 (SHD^SIM) ; tail vertebrae, 102.8 (05-108); hind foot, 58.5 (55-61). Average of 6 adult females from same localities: Total length, 346.3 (340-356) ; tail vertebrae, 99.5 (95-108) ; hind foot, 56.2 (55-59). Skull: Average of 7 adult males from Nushagak, Alaska: Greatest length, 57 (55.7-58.8) ; palatilar length, 28.4 (27-29.5) ; zygomatic breadth, 36.7 (35.4^ 38.5) ; cranial breadth, 23 (22.6-23.7) ; iuterorbital breadth, 12.G (11.6-14) ; postorbital constriction, 13.3 (12.3-14) ; length of nasals, 21.1 (19.8-22.6) ; maxillary tooth row, 12.3 (11.8-12.9). Average of 7 adult females from Nush- agak: Greatest length, 55.3 (54.2-57.1); palatilar length, 27.7 (27-29); zygo- matic breadth, 35 (33.8-36.4) ; cranial breadth, 22.2 (21.5-22.5) ; iuterorbital breadth, 12.1 (11-5-13) ; postorbital constriction, 13 (12-14) ; length of nasals, 12 (11.4-12.4). Remarks. — The Aleutian ground squirrel is closely related to plesius, with which it intergrades in eastern Alaska. Material is lacking to show the exact limits of its range eastward. Certain specimens from Nome, on the Seward Peninsulaj show approach to harrowensis in their larger skulls; intergradation with that race doubtless occurs between Eschscholtz Bay and Point Hope. IQQ NORTH AMERICAN FAUNA [No. 56 Comparison of the type of C. ^^stonei'^ and a good series from the type region with typical ablusus shows no characters to separate the two forms. Hence '■^stoneP (supposed at the time it was described to have come from Wrangell, Alaska) falls in the synonymy of C. p. ablusus, Avhich has several months' priority. In the summer of 1913, 18 ground squirrels of this subspecies were captured at Nushagak and shipped to St. George Island in a single large crate. Although plentifully supplied with green food, they preyed on each other, and while this tendency was overcome to some extent by supplying them with meat, the stock of 18 had been reduced to 5 before they reached their destination. These five, an adult and four young, including both sexes, were liberated on St. George ; at least two survived until May 1914, but by the summer of that year all apparently had disappeared (Osgood, Preble, and Parker, 1915, p. 129). This subspecies is closely similar to C. huxtoni (Allen, 1903c, p. 139) of eastern Siberia, differing chiefly in less intensely tawny coloration, and more blackish tail ; in these characters huxtoni closely resembles G. p. parryii, which, however, is decidedly larger; since huxtoni intergrades in characters with ablusus, it may well be given subspecific status under the name Citellus parryii huxtoni. Specimens examined. — Total number, 274, as follows: Alaska: Alaska Peninsula, 110 (Chignik, 24; Cold Bay, 10; Frosty Peak, 17; Herendeen Bay, 7 ; " Izembek Bay, 1 ; Katmai, 2 ; Kings Cove, 5 ; Kukak Bay, 5 ; Moller Bay, S ; " Morzhovoi Bay, 8 ; Pavlof Mountain, 2 ; Portage Bay, 20; Stepovak Bay, 1) ; Anchorage, 1; " Bristol Bay, 1; Cape Prince of Wales, 4 ; Eschscholtz Bay, 4 ; Golofnin Bay, 1 ; Jennie Creek, Mount Mc- Kinley Park, 1 ; Kakhtul River, 4 ; Kanulik, 3 ; Kavalga Island, 2 ; Kokwok River, 1; Lake Aleknagik, 20; Lake Clark, 4; Mount McKinley, 19; Nome, Y . 74 75 Nusiiagak, 14 ; Savage River, Mount McKinley Park, 3 ; Pavlof Moun- tain, 1; " Swan Lake (Mulchatna-Chulitua Portage), 4; Teller, 1; '' Togiak, 1 ; Unalaska Island, 55 ; Unimak Island, 11 ; Ushagat Island, 2. CITELLUS PARRYII NEBULICOLA Osgood Shumagin Geound Squieeel Citellus neluUcola Osgood, Biol. Soc. Wash. Proc. 16: 26, Mar. 19, 1903. Type. — Collected on Nagai Island, Shumagin Islands, Alaska, June 24, 1893, by C. H. Townsend ; female adult, skin and skull, no. 69145, U. S. Natl. Mus. _ Range. — The Shumagin Islands (Nagai, Simeonoff, and Koniuji), Alaska (fig. 8). Zonal range: Hudsonian. External characters. — Very similar in color to G. p. ablusus, but smaller, with shorter tail and hind feet. Compared with G. kodia- censis: Size smaller; coloration of upper parts more brownish or ochraceous (less grayish) ; under parts darker; tail in summer pel- age more tawny (less blackish). Granial characters. — Skull similar to that of kodiacensis and ablusus but averaging smaller, with relatively longer tooth row; closely similar to that of G. p. plesius, but nasals slightly longer, narrower at posterior end. and elevated along the median suture. In two of the skulls examined the posterior loph on 7n ^ is discontinuous, in this character shov/ing approach to kodiacensis. '^Amer. Mua. Nat. Hist. "•^ Mus. Comp. Zool. ■^ Colorado Mus. Nat. Hist. ''^ Carnegie Mus. 1938] REVISION OF THE GROUND SQUIRRELS IQl Color. — SmiiTner pelage: Top of head and face russet or tawny; eye ring pinkish buff or buffy white; sides of nose pinkish buff, sides of face cinnamon buff, shaded with fuscous; sides of neck, and front legs, ochraceous tawny; upper parts snuff browtn or verona brown, sprinkled with cinnamon and abundantly flecked with creamy white spots; feet cinnamon buff or clay color, the toes pinkish buff; tail above, fuscous black, mixed with cinnamon or cinnamon buff and edged with pinkish buff; tail beneath, russet or mikado brown, tipped with fuscous black; under parts clay color, shading to pinkish buff on tliroat. Winter pelage: Upper parts similar to the summer pelage but much more whitish, the snuff brown hairs more extensively tipped with white, and the shoulders and sides pale smoke gray ; tail above, fuscous black, faintly shaded with sayal brown and edged with buffy white ; tail beneath, snuff brown or cin- namon brown, tipped with black; feet pale pinkish buff; under parts white, faintly shaded with pale pinkish buff. ' Molt. — A specimen taken May 16 is in worn winter pelage, showing new summer fur appearing in scattered patches on the head and back. Measurements. — Average of 3 adult males (measured dry) : Tail vertebrae, 79.7 (77-S2) ; in 8 adults (4 males, 4 females) the hiud foot (dry) averages r)2.1 (50-55.7). Skull: Average of 4 adult females: Greate.'^t length, 52.6 (50.7- 55.4) ; palatilar length, 20.2 (25.5-27) ; zygomatic breadth, 33.7 (32-35) ; cranial breadth, 21.7 (21.1-22.2) ; interorbital breadth, 11.4 (11.1-11.8) ; postorbital constriction, 12 (11-13.2) ; length of nasals, 19.4 (18.2-20) ; maxillary tooth row, 11.5 (11.3-11.7). Remarks. — This depauperate insular race shows relationship both to ablusus of the mainland and to kodiacensls of Kodiak Island. The material at hand is too limited to show clearly its exact rela- tionship to the other forms of the species, but since its characters overlap those of ahlusus it is assigned a subspecific relationship with that race. Specimens examined. — Total number, 15, as follows: Alaska: Shumagin Islands, 15 (Nagai Island, 10; Koniu.ii Island, 1; Simeonof Island, 4). CITELLUS PARRYII LYRATUS ILu.l and Gilmorb St. Lawkence Island Gkound Squikrel (Pis. 24, B; 29, B) Citellus lyratus Hall and Gilmore, Calif. Univ. Pubs., Zool. 38: 396, Sept. 17, 1932. Type. — Collected at Iviktook Lagoon (about 35 miles northwest of Northea.st Cape),^^ St, Lawrence Island, Beriag Sea, Alaska, July 7, 1931, by Raymond M. Gilmore; male adult, skin and skull, no. 51172, Mus. Vert. Zool. (orig. no. 1738). Range. — St. Lawrence Island, Bering Sea, Alaska (fig. 8). Zonal range: Arctic. External characters. — Similar to C. p. ahlusus, of the Alaska Peninsula, but upper parts paler and more grayish (less brownish) ; under parts, sides of nock, legs, and feet paler buff; tail longer and more grayish (less tawny) above and paler beneath. Compared " Location as defined by R. M. Gilmore, August 1933. 102 NORTH AMERiaVN FAUNA [No. 56 with C. p. nebulicola: Size larger; colors paler throughout; tail above mainly blackish or grayish rather than tawny. Cranial characters. — Skull similar in size and proportions to that of dblusus, differing from it in the absence of a prominent sagittal crest, the temporal ridges being lyrate in shape, meeting at the posterior end only in old age to form a very slight crest ; nasals rela- tively broader at posterior end ; posterior loph on m ^ well developed and continuous (as in G. huxtoni and ablusus). Color. — Summer pelage (July) : Top of head mikado brown; sides of face pinkish buff; front legs and sides of neck cinnamon buff; general tone of upper parts light brown, heavily spotted with white, the individual hairs plumbeous at base, then light pinkish buff, then pale fuscous, and tipped with white ; thighs cinnamon buff ; hind feet pinkish buff; under parts cinnamon buff, the throat clay color; tail above (much worn), grayish white, shaded with dull buffy, the tip fuscous or fuscous black; tail beneath, dull, pale russet, edged with grayish white and tipped with fuscous black. Worn pointer pelage (June 23 and 25) : Upper parts chiefly drab or wood brown; sides grayish white; feet pale pinkish buff"; under parts white or dull cinnamon buff. Molt. — The molt apparently takes place in June or early in July; specimens taken June 23 and 25 are in badly worn winter pelage, with new hair showing in patches on the head, back, and under parts. Measurements. — Average of 4 adults (3 males, 1 female) from type locality: Total length, 370 (350-381) ; tail vertebrae, 107 (97-114) ; hind foot, 57.2 (54- 60). Skull: Average of 7 adult males: Greatest length, 57.4 (56.2^58.7); palatilar length, 28.7 (28-29.5) ; zygomatic breadth, 36.6 (35.8-37.3) ; cranial breadth, 22.9 (22.2-23.3) ; interorbital breadth, 12.8 (12.1-13.9) ; postorbital con- striction, 13.8 (13.2-14.1) ; length of nasals, 21.2 (20.5-21.7) ; maxillary tooth row, 12 (11.8-12.4). Average of 4 adult females: Greatest length. 54.3 (53- 56.6) ; palatilar length, 27.4 (27-28) ; zygomatic breadth, 34.2 (33.4-34.9) ; cranial breadth, 22 (21.5-22.6) ; interorbital breadth, 11.8 (11.6-12.2) ; post- orbital constriction, 13.4 (13-13.9) ; length of nasals, 19.8 (19.2-20.4) ; maxillary tooth row, 11.9 (11.5-12.3). RcTYiarks. — The St. Lawrence Island ground squirrel seems to be most nearly related to the form occurring at Emma Harbor, Siberia,^^ which in turn is very close to allusus of the Alaska Peninsula, but differs from it in slightly paler coloration and in having a longer tail. In skull characters, also, lyratus agrees with the Asiatic species in the lyrate shape of the temporal ridges and in tooth characters. C. huoe- toni, from Gichiga, Siberia, is decidedly richer (more tawny) in color than either lyratus or ahlusus, and has the upper surface of the tail more ochraceous, less suffused with black. The present form is much more grayish (less tawny) than either ahlicsus or huxtoni. It is decidedly smaller, as well as paler colored, than paiTyii of the Arctic coast of Alaska. It differs from C. kodiacensis in paler colors of the dorsal surface, feet, and tail, coarser spotting, and in the crown pattern of the last upper molar. Specimens examined. — Total number, 41,^° from St. Lawrence Island. Tsrptjg ground squirrels of the Chukchi Peninsula (Emma Harbor, Plover Bay, and Koliuchin Bay) may prove to be referable to C. stejnegeri of Kamchatl^a, but the single specimen (the type) of stejnegeri now available is too young and too much worn to permit of satisfactory comparison. ■'s 15 in Mus. Vert. Zool. 1938] REVISION OF THE GROUND SQUIRRELS 103 CITELLUS KODIACENSIS (Aixen) KoDiAK Ground Squibbel Spermophilus parryi var. kodiacensis Allen, Boston See. Nat. Hist. Proc. 16: 292, 1874. [Spermophilus empeti-a] var. kodiacensis Allen, Monog. North Amer. Rodentia, p. 839, 1877. [Citellus parryi] kadiacensis Trouessart, Cat. Mamm., Sup., p. 338, 1904. Lectotype ^^ — Collected on Kodiak Island, Alaska, June 1868, by Ferdinand Bischoff ; female adult, skin and skull, no. ^^^j^, U. S Natl. Mus. Range. — Kodiak Island (fig. 8). Zonal range: Hudsonian. External characters. — Similar to G. parryii ahlusus but dorsal spots smaller and more abundant (though sometimes nearly obsolete) ; general tone of upper parts in summer pelage more grayish (less suffused with ochraceous). Cranial characters. — Skull similar to that of ahliisus but molar teeth averaging slightly smaller ; m ^ with posterior loph poorly de- veloped and often not continuous, but broken by a median sulcus; temporal ridges lyrate in shape (as in G. p. lyratus) not uniting pos- teriorly in old age to form a prominent crest. Golor. — Summer felagc. Head and front of face tawny or pale russet, (this color reaching back only to front border of ears) ; sides of nose pinkish buff; sides of face and neck cinnamon buff mixed with fuscous, shading to ochraceous tawny on throat and base of fore legs; upper parts from crown to root of tail mixed fuscous and cinnamon buff (the general tone near snuff brown) , extensively tipped with buffy white, usually appearing as small irregular spots; shoul- ders washed with cinnamon buff; sides of body like back but more grayish (less brownish) ; feet clay color or pinkish buff; tail above chiefly fuscous black, mixed with tilleul buff and bordered with the same; shaded near base with sayal brown; tail beneath, sayal brown or mikado brown, much mixed with buff, the tip fuscous black; under parts cinnamon buff or pinkish buff. ^Y inter pelage : (April and May specimens) : Similar to the summer pelage but tips of hairs on upper parts more whitish, especially on shoulders; sides of head, neck, and body mainly grayish white, with little buff; feet pinkish buff or buffy white ; under parts grayish white, faintly washed with pinkish buff. Measurements. — Average of 10 adult males from Kodiak Island : Total length, 358.2 (332-400) ; tail vertebrae, 96.5 (81-112) ; hind foot, 56.4 (52-60). Aver- age of 10 adult females from same locality : Total length, 353.2 (333-375) ; tail vertebrae, 96.4 (77-104) ; hind foot, 54.7 (51-58). Skull: Average of 10 adult males from Kodiak Island: Greatest length, 56.2 (55-57.8); palatilar length, 28 (27-29) ; zygomatic breadth, 36.8 (35.7-37.6) ; cranial breadth, 23.3 (22.9-24) ; interorbital breadth, 12.3 (11.8-13.6) ; postorbital constriction, 12.5 (11.4-14.2) ; length of nasals, 21 (19.6-21.9) ; maxillary tooth row, 11.7 (11.2-12.7). Aver- age of 10 adult females from same locality: Greatest length, 54.4 (51.8-55.7) ; palatilar length, 27.2 (25.5-28) ; zygomatic breadth, 35.5 (34.5-36.8) ; cranial breadth, 22.6 (21.7-23.2) ; interorbital breadth, 12 (11.5-12.5) ; postorbital constriction, 12.5 (11.5-13.7) ; length of nasals, 20.5 (18.5-21.3) ; maxillary tooth row, 11.4 (10.3-12). *> No type was designated : this specimen is tlie only one of tiiose listed by Allen in liis monograpli (1877, p. 848), now remaining in tiie National Museum collection It is liereby designated as a lectotype. 104 NORTH AMERICAN FAUNA [No. 56 Remarks. — The Kodiak ground squirrel is closely related to ablusus^ inhabiting the nearby mainland, but since it differs in both cranial and color characters it is considered a distinct species. Os- good states (1903, p. 27), on the authority of a native, that the spermophiles on Kodiak Island Trere introduced from North Semidi Island; no specimens from the latter island have been seen, but the rather pronounced characters of kodiacensis indicate that the species probably has occupied Kodiak Island for a long period. Specimens examined. — Total number, 45, from Kodiak Island. CITELLUS OSGOODI (Merbiam) Yukon Vaixkt Ground Squtreel (Pis. 24, C; 29, 0) Spermophilus osgoodi Merriam, Wash. Acad. Sci. Proc. 2 : 18, Mar. 14, 1900. [Citellus] osgoodi Osgood, Biol. Soc. Wash. Proc. 16: 27, 1903. 7'2/;?e.— Collected at Fort Yukon, Alaska. April 29, 1877, by L. M. Turner; male adult, skin and skull; no. iHM; U. S. Natl. Mus. (orig. no. 1635). Range. — Tlie Yukon Valley, from a point about 25 miles above Circle to the Yukon Flats, west of Fort Yukon and possibly to the mouth of the Tanana (Osgood, 1900, p. 31) (fig. 8). Zonal range: Hudsonian. External characters. — Similar to C. pann/ii parry ii but tail longer; coloration darker (more reddish) and dorsal spots smaller; feet darker. Cranial charaxiters. — Slmll closely similar to that of parryii ; audi- tal bullae averaging slightly smaller and less inflated. Color. — Summer pelage (July) : Entire top of head (nose to occi- put) chestnut or bay; sides of nose tawny or ochraceous tawny; sides of head, neck, and shoulders hazel or chestnut, sometimes washed with ochraceous buff and streaked with blackish; ears ochraceous tawny on both surfaces; dorsum mars brown, more or less overlaid with pinkish buff, and thickly flecked with spots of buffy white; anterior sides hazel; posterior sides like back but more washed with buffy ; legs and feet hazel ; under parts hazel or amber brown ; tail above, black, more or less overlaid and edged with cinnamon buff or tilleul buff; tail beneath, mikado brown, shaded with cinnamon buff and broadly tipped with black. Winter pelage (Octo- ber-April) : Head as in summer; sides of nose and cheeks cinnamon buff or ochraceous buff; nape washed with cinnamon buff or tawny; shoulders and fore back extensively overlaid with pale smoke gray and sides heavily washed with same; legs and feet tawny; under parts tawny or ochraceous tawny, sometimes irregularly shaded with cinnamon buff and buffy white; tail hazel beneath. Melanisti^ phase : About 20 percent oi the specimens examined are in this phase ; most of them are solid blackish brown, more or less sprinkled with buffy grayish hairs and with patches of bay on the nose ; several are pure black on the entire body, with a few brownish hairs at the tip of the tail ; one young specimen is sprinkled with grayish and buffy spots on a blackish ground, the nose and feet washed with brownish. Molt. — The spring molt begins in late June ; specimens taken near Circle June 27-30 show new pelage covering most of the under parts 1938] REVISION OF THE GROUND SQUIRRELS 105 and appearing on the head, shoulders, and front legs; others taken the same dates are in complete siinmier pelage. A specimen from Fort Yukon taken October 15, 1885, was apparently acquiring winter pelage, but the method of molting is not clearly shown. Measurements. — Average of 10 adult males from near Circle, Alaska : Total length, 456.4 (437-475) ; tail vertebrae, 141.7 (131-153) ; hind foot, 62.7 (61-65). Average of 10 adult females from same locality: 433 (420-462) ; 136 (126-147) ; 60.3 (57-63). Skull: Average of 10 adult males from Circle, Alaska: Greatest length, 63.1 (60.2-65.S) ; palatilar length, 32.4 (31-34) ; zygomatic breadth, 41.5 (38.6-44.3) ; cranial breadth, 24.5 (24-25.5) ; interorbital breadth, 14 (12.7-15) ; postorbital constriction, 13.4 (12.5-14.8) ; length of nasals, 24 (23-25) ; maxillary tooth row, 14 (13.3-14.6). Average of 10 adult females from same localitv : Greatest length, 60.1 (58-61.8) ; palatilar length, 29.9 (28-31) ; zygomatic breadth, 39.3 (37.4-42) ; cranial breadth, 24 (23.3-25.1) ; interorbital breadth, 13 (12.3-14) ; postorbital constriction, 13.6 (13-14.4) ; length of nasals, 22.6 (21.8-23.4) ; maxillary tooth row, 13.9 (13.4^-15). Weight of males, 1^ to 2^ pounds (average about 1% pounds) ; of females, 114 to 1% pounds (average about iy2 pounds) (Osgood. 1909, p. 23). Remarks. — The Yukon Valley ground squirrel is the largest known member of the farinjii group; in cranial measurements and size of hind feet it averages about the same as parryii but exceeds it in length of tail. It has a very restricted range along the Yukon River and although closely related to parryii apparently does not intergrade with it. O. J. Murie, in ascending the Porcupine, saw no squirrels until near the mouth of Coleen River; specimens taken there and at Salmon Trout River and Rampart House are nearly typical parryii^ showing no approach to osgoodi. The lower limit of the species in the Yukon Valley is not definitely known, but the upper limit has been determined by Osgood as a point about 25 miles above Circle. No ground squirrels of any kind occur along the Yukon above that point until near the mouth of Pelly River, where the much smaller form, C. p. plesiu^s., finds its lower limit. Although specimens of this fine squirrel have been in the National Museum collection since 18G1, when Kennicott collected a consider- able series, they were not recognized as distinct from parryii until 1900, when Merriam, after Osgood had recognized it in the field, de- scribed the species as new. Specimens examined. — Total number, 62, as follows : Alaska: Yukon River, 62 (Circle, 1; Fort Yukon, 3; mouth of Porcupine River, 1 ; ^'^ 10 miles above Hess Creek, 1 ; 20 miles above Circle, 55 ; Yukon Flats, 1 ) . ** Mus. Comp. Zool. 106 NORTH AMERICAN FAUNA [No. 56 Subgenus ICTIDOMYS Allen [Characters and synonymy on p. 41] Key to Species and Subspecies c\ Dorsal area striped. 6\ Larger ; hind foot more tlian 36 mm tridecemlineatus (p. 107) &^ Smaller ; hind foot less than 36 mm. c\ Dark stripes distinctly reddish (russet or mars brown), texensis (p. 110) c^. Dark stripes not distinctly reddish. d\ Colors paler (dark stripes snuff brown, walnut brown, or cinnamon brown). e\ Larger (skull length more than 37 mm) arenicola (p. Ill) e^. Smaller (skull length less than 37 mm) parvus (p. 117) d^ Colors darker (dark stripes chestnut brown, mummy brown, or sepia). e\ Larger (skull length more than 37.5 mm) palUdus (p. 112) e'. Smaller (skull length less than 37.5 mm). f. Dark stripes mummy brown alleni (p. 114) f. Dark stripes chestnut brown. f/\ Under side of tail russet nwnticola (p. 116) g^. Under side of tail chestnut brown liollisteri (p. 115) a'. Dorsal area spotted. 6\ Dorsal spots in linear series. c\ Larger ; skull length more than 45 mm mexicanus (p. 119) cf. Smaller; skull length less than 45 mm parvidens (p. 121) b\ Dorsal spots not in linear series. c^. Dorsal spots and under parts buffy perotensis (p. 132) c^ Dorsal spots and imder parts white. d\ Smaller (skull length less than 36.5 mm). e\ Dorsal spots distinct pratensis (p. 128) er. Dorsal spots not distinct crypt ospilotus (p. 130) d^ Larger (skull length more than 36.5 mm). e^. Dorsal spots indistinct or obsolete. f. Larger (skull length 39-42.5) major (p. 126) f. Smaller (skull length 37.7-39.9) ohsoletus (p. 130) e'. Dorsal spots distinct. f. Dorsal spots smaller (habitat central Mexico). g^. Darker spllosoma (p. 122) g-. Paler pallescens (p. 124) f. Dorsal si)Ots larger (habitat United States and northern Mexico). f/\ Smaller (skull length less than 38 mm) canescens (p. 125) g\ Larger (skull length more than 38 mm). h^. Audital bullae larger major (p. 126) 7i^. Audital bullae smaller annectens (p. 128) CITELLUS TRIDECEMLINEATUS GROUP CITELLUS TRIDECEMLINEATUS (Mitchill) [SynonjTuy under subspecies] Specific characters. — Size small to medium ; hind foot, 28-41 Trmn ; tail, 60-108; skull _ length, 34-45.8. Skull relatively long, narrow, and weakly built (in comparison with C. toionsendii mollis or C. w. washingtoni), the brain case usually longer than broad; interorbital region relatively long, the supraorbital margins only slightly ele- vated; rostrum long and tapering gradually; zygomata rather stout, but not widely expanded ; molarif orm tooth rows slightly convergent posteriorly; audital bullae moderately inflated, the external meatus tube short. Color. — Upper parts marked with a series of alternating light and dark longitudinal stripes; the dark stripes are usually five in num- ber, brownish or blackish in color and extending down the median 1938] REVISION OF THE GROUND SQUIRRELS X07 line of each is a series of squarish white or buffy white spots ; alter- nating with the dark stripes are about six narrower whitish stripes ; on the sides are several additional, more or less indefinite, stripes and spots ; in some races, some of the light dorsal stripes are broken into spots. CITELLUS TRIDECEMLINEATUS TRIDECEMLINEATUS (Mitchill) Thibteen-lined Ground Sqxjireei. Sciurus tridecem-lmeatus MitchiU, Medical Repository (n. s.) 6 (21) : 248. 1821. Arctomys hoodii Sabine, Linn. Soc. London. Trans. 13: 590, 1822 (Carlton House, Saskatchewan). Arctomys tridecemlineata Harlan, Fauna Amer., p. 164, 1825. Spermophihis tridecemlineatus Audubon and Bachman, Quad. North Amer. 1: 294, 1849. [Citellus] tridecimlineatus Trouessart, Cat. Mamm., Sup., p. 341, 1904. . Type. — None designated. "Brought by Professor Douglas, of the United States Military Academy, from the region bordering the sources of the river Mississippi, in November 1820" (Mitchill, 1. c). Type locality fixed in "central Minnesota" by J. A. Allen (1895b, p. 338). Range. — Southern parts of Alberta, Saskatchewan, and Manitoba ; northern Montana; eastern parts of North Dakota, South Dakota, and Nebraska ; northeastern Kansas ; northern Missouri ; all of Iowa ; most of Minnesota and Wisconsin; Lower Peninsula of Michigan; northern parts of Illinois and Indiana; and southwestern Ohio. North to Athabaska Landing, Alberta; east to Fairfield County, Ohio; south to central Kansas; west to Red Deer, Alberta, and St. Mary Lake, Mont. (fig. 9). Zonal range: Transition and Upper Austral. External characters. — Size large ; coloration dark ; all light stripes continuous, not broken into spots; larger than C. t. texensis and averaging more blackish (less reddish). Occasional specimens in winter pelage are almost as reddish as texensis^ but always larger. Cranial characters. — Skull large (for the species) ; somewhat sim- ilar to that of G. tvashingtoni washingtoni but differing in the char- acters of the subgenus; narrower brain case; longer rostrum; zygomata less spreading; postorbital processes shorter and slenderer; anterior premolar relatively smaller; upper incisors shorter and stouter. Color. — Swnmer pelage (July-September) : Sides of nose cin- namon buff; eye ring pinkish buff; cheeks mixed fuscous and cin- namon buff; ear rim and sides of neck cinnamon or ochraceous tawny; dark dorsal stripes dark fuscous or fuscous black, the five median ones each with a row of squarish or rectangular buffy white spots down the center: light dorsal stripes buffy white; front legs and feet cinnamon buff; hind legs mikado brown or russet, the feet cinnamon buff; tail above, fuscous black, mixed with sayal brown and bordered with pinkish buff; tail beneath, russet or mikado brown at base, shading to ochraceous buff or cinnamon buff toward tip, more or less mixed, especially near tip, with fuscous black; lower sides cinnamon buff, shading to pinkish buff on throat and belly; chin creamy white. Winter pelage (April and May) : Similar to the summer pelage but dark dorsal stripes mars brown or chest- 108 NORTH AMERICAN FAUNA [No. 56 nut brown, and light dorsal stripes creamy white rather than buffy white. Measurements. — Average of 10 adult males from Fort Snelling and Elk River, Minn.: Total length, 284.9 (274-297); tail vertebrae, 104.7 (90-132); liind foot, 39.8 (38-41). Average of 10 adult females from Minnesota and Wisconsin: Total length, 267.9 (239-285) ; tail vertebrae, 93.6 (80-103) ; hind foot, 37.3 (35-40). Skull: Average of 10 adults from Elk River and Fort Snelling, Minn.: Greatest length, 44 (43.2-45.8) ; palatilar length, 20.5 (20-21) ; Figure 9. — Distribution of the subspecies of Citellus tridecemlineatus: 1, C. t. tridecemli- neatus; 2, C t. pallidus ; 3, G. t texensis; 4, C. t. arenicola; 5, C. t. alleni: 6, C. t. parvus; 7, C. t. hollisteri; 8, 0. t. monticola. zygomatic breadth, 25.1 (24.4-26.4) ; cranial breadth, 17.6 (17.3-18) ; inter- orbital breadth, 8.1 (7.7-9) ; postorbital constriction, 11 (10.2-11.4) ; length of nasals, 15.3 (14.3-16.8) ; maxillary tooth row, 7.9 (7.6-S.4). Average of 8 adult females from same localities: Greatest length, 42.7 (41.2-44.2) ; palatilar length, 19.7 (18.5-21) ; zygomatic breadth, 24.3 (23-25.5) ; cranial breadth, 17.3 (16.3-18.1) ; interorbital breadth, 8.3 (7.3-9.1) ; postorbital con- striction, 11.1 (10.5-11.8) ; length of nasals, 14.9 (14.2-15.6) ; maxillary tooth row, 7.8 (7.4-8.2). V/eiffht. — Wade (1930, p. 170) gives the weights of four males as ranging from 170-243 g ; of four females, from 14rt-211 g. 1938] REVISION OF THE GROUND SQUIRRELS 109 Remarks. — The typical race of the striped ground squirrel has an extensive range in the upper Mississippi Valley and the northern plains and is an abundant animal over most of its range. Consid- erable individual and seasonal variation is shown in nearly every series of this race, specimens taken in midsummer being the darkest and those taken in late spring decidedly paler and more tawny (less brownish). Specimens from near the northern limits of its range (Edmonton, Alberta) are not appreciably different from typical specimens, but those from northwestern Montana (St. Mary Lake and Choteau) are somewhat paler, thus showing approach to C. t. ■pallidus. Intergradation with the latter is shown also, by numerous specimens from central North Dakota, South Dakota, Nebraska, and Kansas. A large series from Knoxville, Iowa, shows approach to texeTisis in slightly smaller size and in the reddish tone of the under side of the tail. The under parts are more strongly buffy than in either tridecemlineatus or texensis. A small series from Onaga, - Kans., is typical. The large series examined from Leavenworth and Douglas Counties, Kans., is intermediate between tridecemlineatus and texensis.^ but a little nearer to the former; the one summer speci- men is clearly tridecemlineatus; the skulls are intermediate in size. Specimens examined. — Total number, 44.5, as follows: Alberta: Chief Mountain Lake, 1; Red Deer, 3; South Edmonton, 5; Sturgeon River (25 miles north of Eclmontoi!). 1. Illinois: Chicago, 15;" Kansas, 1; Riverdale (Cook County), 1;" Warsaw, 1; Waukegan, 1;" Wheatland To'.vnshiri (Will County). 1."' Indiana: La Fayette (8 miles east), 1; Lake Village (Newton County), 1;" Logansport, 1;^ Montezuma (Parke County). I:*" Notre Dame. 2;*^ Pine Station (Lake County), 1; Roseland (St. Joseph County), 1;" Ro.val Cen- ter, 2; South Bend, 1;" Wahash Township (Tippecanoe County), 1. Iowa: Ames, 1;** Burlington, 22; Knoxville, 16; Luxemhurg, 1.** Kansas: Douglas County, 12;** Fort Leavenworth, 1; Fort Riley, 1; Lawrence, 8 ;" *° Leavenworth, 5 f Onaga, 5. Manitoba: Carherry. 34; Red River Settlement, 1. Michigan: Alma, 2;'' Ann Arbor, 13;*" Birchwood Beach (Berrien County), 1;" Boyne Falls (Charlevoix County), 1;'^ Boyne Valley (Charlevoix County), 1;" Byron (Shiawassee County), 2;*^ Chelsea, 1:*^ Douglas Lake (Cheboy- gan County), 1;** Harbert (Berrien County), 1 ;" Higgins Lake (Roscom- mon County), 1;" Le Roy (Osceola County). 2;^ Lucerne (Oscoda County), 1 f^ Manchester, 1 ;" Montmorency County, 2 ;*^ Otsego County, 1 ;" Portage Lake (Washtenaw County), 3;*^'" Warren Preserve (Berrien County), 2;** Waterloo (Jackson County). 1.** Minnesota: Brown Valley, 3; Elk River, 21; Fort Snelling (Hennepin County), 4;" Geneva Lake (Freeborn County), 1: Germantown (Marshall County), 1; Goodhue, 3;" Hutchinson, 1; Ortonville, 2; Princeton (Benton County), 1; Waseca County, 1.*^ Montana: Bear Paw Mountains (20 miles southeast of Port Assiniboine) , 1; Blackfoot Agency (Glacier County), 1; Choteau. 1; Johnson Lake (Roose- velt County), 1; St. Mary Lake. 3: St. Mary River (15 miles below St. Mary Lake), 1: Zortman (Phillips County), 1. Nebraska: Broken Bow, 1;" Columbus, 4; Glen (Sioux County), 1;** North Platte, 2;»* Verdigris, 1. North Dakota: Bismarck, 2; Bottineau, 1; Braddock, 2-^ Buford (Williams County). 3; Casselton, 1; Crosby. 1; Dawson (Kidder County), 1: Devils Lake, 1 ;'=' Drayton, 1 ; Ellendale, 1 ; Fairmount, 7 : Fargo, 3 ; Fort Berthold (McLean County), 1; Fort Buford (Williams County), 3; Grand Forks. 4; Grafton, 3; Grinnell (Williams County), 1; Hankinson, 2; Harwood (Cass County), 1; Lidgerwood, 1; Ludden (Dickey County), 2; Minot, 4;"^ Oakes, 5; Old Fort Union (near Buford), 4; Pembina. 9; Portland, 1; Stark- weather, 2; Steele, 8;"= Streeter, 1; Stump Lake, 2; Towner, 3; Turtle Creek (near Washburn), 3; Valley City. 3; Walhalla, 1; Washburn, 1; Yellowstone River (mouth), 2; Zeeland, 1. See footnotes on page 110. 210 NORTH AMERICAN FAUNA iNo. 56 Ohio: Bainbridge (Ross County), 9;^' Circleville, 1;*" Lancaster, 6. Saskatchewan : Grenfell, 1 ; Indian Head, 3 ; Livelong, 2 ; "" Prince Albert, 2 ; ^ Wingard, 4. South Dakota: Plandreau, 2; Fort Randall (Gregory County), 1; Mitchell, 2; Pierre, 2 ; Lake Traverse, 5 ; Vermillion, 1 ; "^ White Lake (Avirora County), 1. Wisconsin: Bay Settlement (Brown County), 3;** Beaver Dam, 14;°^ Ben- derville (Brown County), 1;^ Bussyville ( = Sumner, Jefferson County), 1; Camp Douglas (Juneau County), 1; Clark County, 2;^^ Danbury (Burnett County), 2; Delavan, 1; Devils Lake (Sauk County), i; Endeavor, 2; Friendship, 2; Green Lake, 4; Herbster (Bayfield County), 2; Holcombe (Chippewa County), 2; Kelly Lake (Oconto County), 1; La Crosse, 2; Long Lake (Washburn County), 1; Mather (Juneau County), 2; Namakagon Lake (Bayfield County), 1; Nashotah (Waukesha County), 2; Orienta (Bayfield County), 2; Prescott, 1; Racine, 7; Rib Hill (Marathon County), 6; Solon Springs, 2; Stevens Point, 1; Three Falls (15 miles west of Crivitz, Marinette County), 2f* Wauzeka (Crawford County), 1. CITELLUS TRIDBCEMLINEATUS TEXENSIS (Mebriam) Texas Stetped Ground Squierel , Sperniophilus tridecemlineatus texensis Merriam, Biol. Soc. Wash. Proc. 12 : 71, Mar. 24, 1898. Sperrnophilus (Ictldomt/s) tridecemlineatus dadius Bangs, New England Zool. Club Proc. 1: 1, 1899 (Stotesbury, Mo.). [Citellus tridecemlineatus'] texensis Trouessart, Cat. Mamm., Sup., p. 342, 1904. Type. — Collected at Gainesville, Tex., April 15, 1886, by George H. Ragsdale; male adult, skin and skull, no. 186471, U. S. Natl. Mus. (formerly no. f|^, Merriam collection). Range. — Prairie region of middle eastern portions of Texas and Oklahoma; north to southeastern Kansas (Cairo and Garden Plain) ; east to southwestern Missouri (Stotesbury and Golden City) ; south to Bee County, Tex. ; west to Vernon, Tex., and Mount Scott, Wichita Mountains, Okla. (fig. 9). Zonal range: Lower Austral. Extejmal characters. — Similar to C. t. tridecemlineatus but smaller, with upper parts and under side of tail paler and more reddish. Cranial characters. — Skull similar to that of tridecemlineatus but smaller, and relatively broader across brain case and zygomata. Color. — Winter pelage (April) : Dark dorsal stripes russet or mars brown; light stripes and spots creamy white; eye ring buffy white; lower sides and under parts cream color or pinkish buff; fore and hind feet pinkish buff or buffy white; tail above, same color at base as the back, but more or less overlaid with whitish hairs, and shading to cimiamon buff on distal portion, the hairs on sides of tail tilleul buff at tips with a subterminal band of fuscous black ; tail beneath, russet in center, edged and more or less overlaid with tilleul buff. Summer pelage (August) : Dark strikes chestnut brown; light stripes buffy white to pale cinnamon buff. Measurements. — ^Average of 10 adults (4 males, 6 females) from Texas (Ver- non, Wichita Falls, Henrietta, Gainesville) : Total length, 258 (227-267) ; tail vertebrae, 92 (80-102); hind foot, 34 (33-36). Slvull: Average of 11 adults (4 males, 7 females) from Texas (Gainesville, Vernon, Henrietta, Richmond, *2 Univ. Michigan Mus. Zool. *3 p. F. Hickie collection. ^ Univ. of Notre Dame. ^Kansas Univ. Mi.is. Nat. Hist. *" Cornell Univ. Mus. ®^Amer. Mus. Nat. Hist. ** Univ. Nebraska. 89 Cleveland Mus. Nat. Hist. 0" William T. Shaw collection. »i South Dakota State Biol. Survey. »= Field Mus. Nat. Hist. 1938] REVISION OF THE GROUND SQUIRRELS m Wichita Falls) : Greatest length, 40.4 (39.5-42.1) ; palatilar length, 19 (18.2-20) ; zygomatic breadth, 24.2 (23.1-25.8) ; cranial breadth, 17.8 (16.9-18.9) ; inter- orbital breadth, 8 (7-8.4) ; postorbital constriction, 11.9 (10.7-12.6) ; length of nasals, 14.3 (13.2-15.6) ; maxillary tooth row, 7.5 (7.3-8). Remarks. — The Texas ground squirrel is a well-marked form, characterized especially by its reddish coloration. Specimens from Kiowa and Cairo, Kans., and Alva, Okla,, are paler than typical specimens, thus showing apf>roach to G . t. arenicola. A single speci- men from Dimmitt, Tex., seems referable here, although on geo- graphical grounds it should be within the range of arenicola. The series from Stotesbury, Mo., which formed the basis of '"'"'badius''' of Bangs is closely similar in color to texensis., winter specimens being practically indistinguishable ; summer specimens are slightly darker (more blackish) and the skulls are slightly larger. The series is thus intermediate between texensis and tridecemlineatiis but with too slight characters for recognition by name. Specimens examined. — Total number, 72, as follows: Kansas : Anderson County, 1 ; " Belle Plaine, 2 ; Columbus, 1 ; °^ Garden Plain, 1 ; Independence, 2."^ Missouri: Golden City, 5; Stotesbury (Vernon County), 12;"* Washburn (Barry County), 6. Oklahoma: Apache, 1; Arnettville, 1;*° Fort Reno (Canadian County), 2; Law- ton, 1; Mount Scott P. O. (Comanche County), 14; Noble, 2; '^ Norman, 2:*' Orlando, 3. Texas: Cooke County, 1; Gainesville, 2; Henrietta, 3; Richmond, 4; Vernon, 4; Wichita Falls, 2. CITELLUS TRIDECEMLINEATUS ARENICOLA Howell Sandhill Stetped Ground Squierkl Citellus tridecemlineatus arenicola Howell, Biol. Soc. Wash. Proc. 41: 213, Dec. 18, 1928. Type. — Collected at Pendennis, Kans., April 22, 1897, by J. Aldeii Loring; male adult, skin and skull; no. 87686, U. S. Natl. Mus. (Bio- logical Survey collection) (orig. no. 3988). Range. — Southwestern Kansas, eastern Colorado, northwestern Texas, northwestern Oklahoma, and eastern New Mexico; north to Logan County, Colo. ; east to Barber County, Kans. ; south to Lub- bock, Tex., and Roswell, N. Mex. ; west to Lincoln County, N. Mex. (fig. 9). Zonal range: Upper Sonoran. External characters. — Similar to G. t. pallidus., but smaller and paler, the dark dorsal stripes snuff brown instead of sepia; similar, also, to G. t. texensis., but smaller and much paler. Granial characters. — Skull similar to that of pallidus., but aver- aging slightly smaller, except in breadth of the cranium; nasals shorter. Golor. — Winter pelage (April 23) : Dark dorsal stripes snuff brown or Front's brown ; light dorsal stripes and spots white, some- times faintly washed v/ith pale buff; tail above, cinnamon buff, shaded with bister, becoming fuscous or fuscous black on distal end, strongly margined with buffy white; tail beneath, tawny on median basal portion, shading to cinnamon on distal portion, edged with fuscous black and tipped with buffy white; feet, under parts, and •* K.insas Univ. Mus. Nat. Hist. •*Mus. Comp. Zool. •» Field Mus. Nat. Hist. 2]^2 NORTH AMERICAN FAUNA [No. 56 sides buffy white. Summer pelage (Lipscomb, Tex., July 8) : Dark dorsal stripes cinnamon brown ; light stripes tilleul buff ; under parts and sides dull buffy white ; hind feet pinJkish buff ; tail as in wmter pelage. Measurements. — Average of 8 adults (4 males, 4 females) from type locality: Total length, 238 (214-295) ; tail vertebrae, 77.7 (71-83) ; hind foot, 32.2 (31-34). Skull: Average of 8 adult males (3 from Pendennls, 5 from Morton County, Kans.) : Greatest length, 39.1 (38.3^0.3) ; palatilar length, 17.9 (17.5- 18.5) ; zygomatic breadth, 23.2 (22.6-24.3) ; cranial breadth, 17.2 (16.8-17.6) ; in- terorbital breadth, 8.1 (7.4-8.9) ; postorbital constriction, 12 (11.6-12.5) ; length of nasals, 13.9 (13.2-14.9) ; maxillary tooth tow, 7.2 (6.8-7.7). Average of 8 adult females from same localities: Greatest length, 38.1 (37.3-39.7) ; palatilar length, 17.7 (17.1-18) ; zygomatic breadth, 22.7 (21.9-23.4) ; cranial breadth, 17 (16.2-17.8) ; interorbital breadth, 7.6 (7-8.2) ; postorbital constriction, 13.5 (13-14.4) ; length of nasals, 13.5 (13-14.4) ; maxillary tooth row, 7 (6.7-7.2). Remarks. — This race is the palest of all the forms of this species. The dorsal stripes are more reddish in tone than in palUdus, m this respect showing approach to texensis. Intergradation with pallidus occurs in eastern Colorado, northwestern Kansas, and western Ne- braska. A large series from Baca County, southeastern Colorado, is typical of arenicola in color, but the skulls are like those of paUidus. Specimens examined. — Total number, 110, as follows : Colorado: Akron, 1 ; '^ Eureka Hill (Cheyenne County), 1; Greeley, 1; Kit Carson County, 1;'" Leroy (Logan County), 1; Monon (Baca County), 6;" Springfield (Baca County), 8; "' Sterling, 5; Tuttle (Kit Carson County), 1 ; Washington County, 2;'"'"MVray, 3;'° Wray (20 miles northwest), 1.'' Kansas: Banner (Gove County), 2;"^ Cairo (Pratt County), 1; Clark County, 1;*" Coolidge (Hamilton County), 1;"* Fowler (Meade County), 2;°^ Grin- nell (Gove County), 2 ; ^ Kiowa, 4; Medicine Lodge 1 ; Morton County, 13 ; ^ Oaklev, 1; Oanica (Kearney County), 2;"* Pendennis (Lane County), 10; Phillipsburg, 1 ; '^^ Scott City, 3 ; Wallace (Wallace County), 1.°* New Mexico: Cabra Springs (6 miles north, San Miguel County), 1; Chico Springs (Colfax County), 1; Clayton, 1; Folsom, 1; Loveless Lake (10 miles northwest of Capitan Mountains, Lincoln County), 1; Preston (Colfax County), 1; Roswell, 1; San Jon (Quay County), 5;^ Tucumcari (25 miles west), 1. Oklahoma: Alva, 4;' Woodward, 3. Texas: Dimmitt (20 miles south), 1; Lipscomb, 3; Lubbock, 2; Mobeetie, 1; Texliue (20 miles east), 1; Washburn, 6. CITELLUS TRIDECEMLINEATUS PALLIDUS (Aixen) Palud Striped Geound Squxrbei, [SpermopMlus trldecemlineatus] var. pallidus Allen, Monog. North Amer. Rodentia, p. 872, 1877. [Citellus tridecimlineatus'] palUdus Trouessart, Cat. Mamm., Sup., p. 341, 1904. SpermopMlus tridecemlineatus oUvaceus Allen, Amer. Mus. Nat. Hist. Bull. 7: 337, 1895 (Custer, S. Dak.), Type. — None designated; type locality, mouth of the Yellowstone River, Mont.* Range. — Plains of Montana east of the Rocky Mountains, eastern Wyoming, northeastern Colorado, northwestern Kansas, western ** Univ. Micbigan Mus. Zool. ^' E. R. Warren collection. '8 Kansas Univ. Mus. Nat. Hist. «9 Colorado Mus. Nat. Hist. * Kansas State Agr. College. 2 Cleveland Mus. Nat. Hist. 8 Two in Field IMus. Nat. Hist. * Cf . Allen (1895b, p. 338) -wliere the type region is designated as "plains of the Lower Yellowstone River." In order to fix the type locality more definitely, specimen number 16237, U. S. National Museum, taken Aug. 18, 1857, at the mouth of the Yellowstone, by F. V. Hayden, is here selected as a lectotype. 1938] REVISION OF THE GROUND SQUIRRELS 1X3 parts of Nebraska and South Dakota, and southwestern North Dakota; north to the Missouri River in Montana, east to the Mis- souri in North Dakota, and to about the 100th meridian in Nebraska and Kansas; south to Ellis and Trego Counties, Kans., and Colorado Springs, Colo. ; west to Casper and Laramie, Wyo., and to Canadian Creek (North Park) and Como (South Park), Colo. (fig. 9). Zonal range : Upper Sonoran and Transition. External characters. — Similar to G. t. tridecemlineatus but smaller and paler. Cranial characters. — Skull similar to that of tridecemlineatus, but decidedly smaller and with relatively broader rostrum and brain case. Color. — Summer pelage (August and September) : Dark dorsal stripes sepia ; light stripes and spots grayish white or ca,rtridge buff ; front and sides of face pinkish buff, washed with pinkish cinnamon on nose; front feet pinkish buff; hind feet cartridge buff, the legs .cinnamon buff or washed vrith cinnamon or clay color; tail above and beneath, cinnamon buff, mixed with fuscous black and overlaid with pinkish buff' ; under parts and lower sides cartridge buff, shaded with pinkish buff. Winter pelage (May 21) : Very similar to the summer pelage, but light dorsal stripes and spots more whitish (less buffy) ; sides of face, neck, and body pinkish buff. Measurements. — Average of 10 adult males from eastern Montana: Total length, 244.2 (214-255); tail vertebrae, 80.7 (60-91); hind foot, 32.9 (31-35). Average of 10 adult females from same section: Total length, 232.5 (220-252) ; tail vertebrae, 82.2 (76-91) ; hind foot, 32.3 (31-35). Skull: Average of 7 adult males from eastern Montana: Greatest length, 39.5 (38-42.1) ; palatilar length, 18.5 (17.5-19.5) ; zygomatic breadth, 23.2 (22.3^24.6) ; cranial breadth, 17.1 (10.6-18.3) ; interorbital breadth, 7.6 (7.2-8.4) ; postorbital constriction, 11 (10-11.7) ; length of nasals, 14.8 (14-15.4) ; maxillary tooth row, 7 (6.7-7.3). Average of 10 adult female.s from same section : Greatest length, 38.8 (30.4- 41.3) ; palatilar length, 18.2 (17-19.8) ; zygomatic breadth, 23.1 (21.9-24.7) ; cranial breadth, 16.8 (15.8-17.9) ; interorbital breadth, 7.3 (6.6-7.8) ; postorbital constriction, 10.6 (9.9-11.3) ; length of nasals, 14.3 (13.4-15.7) ; maxillary tooth row, 7 (6.5-7.4). Remarks. — The pallid ground squirrel is distinctly smaller and paler than the typical race, but larger and darker than C. t. parvus and C. t. arenicola. It was described from the plains of the lower Yellowstone, at the northern edge of its raiige. On the north side of the Missouri River, directly opposite the mouth of the Yellowstone, the squirrels are darker and are referable to tridecemlineatus. In- tergradation with the typical race occurs over a considerable strip of country in the central parts of North Dakota. South Dakota, Ne- braska, and Kansas. Southward, in eastern Colorado and north- western Kansas, this race intergrades with arenicola. Doubtless it intergrades also with C. t. alleni in the foothills of the Bighorn Mountains, but no specimens are available from that section. Four specimens from Casper, Wyo., are typical of pallidus in color, but the skulls are smaller and more like those of parvus. The type series of ''^olivaceus'''' from Custer, S. Dak., has been com- pared with a large series of typical pallidus and is found to agree closely with it. 154970—38 8 11/^ ' NORTH AMERICAN FAUNA [No. 56 Specimens examined. — ^Total number, 314, as follows : Colorado: Barr (Adams County), 3;° Boulder, 1; Canadian Creek (Jackson County), 5; Colorado Springs, 20;'^ Como (Park County), 5; Deer Trail Arapahoe County), 1;^ Denver, 2; Divide (Teller County), 6/ Elbert (6 miles south), 1;' Elbert County (between Mattison and Resolis), 1;" Elk- horn (Larimer County), 1; Fort Collins, 1; Golden, 2; Horsetail Creek (Weld County), 5;^ Loveland, 22; Manitou, 1;'^ Pav^nee Buttes (Weld County), 2; Puma City (Park County), 1;* Simla (12 miles east), 1;^ Tarryall Creek (Park County), 1;^ Valmont (Boulder County), 1. Kansas: Atwood (10 miles east and 27 miles west) , 2 ; * Colby, 1 ; Ellis, 1 ; Hays, 1; Logan County, 3*; North Solomon River (Graham County), 1; Solomon River (Graham County), 1; Trego County, 10; Woodston (Rooks County), 3.' Montana: Albion (Carter County), 1; Baker (10 miles north, 4; Billings, 1; Broadus (10 miles northeast), 1; Capitol (Carter County), 2; Cohagen (16 miles southeast, Garfield County), 2; Crow Agency (Bighorn County), 5; Fort Custer (Bighorn County), 2; Intake (Dawson County), ?.; Little Bighorn River (2 miles north of Wyoming border), 1; Little Dry Creek (Garfield County), 1; Medicine Rocks (Carter County), 3; Melstone (Mus- selshell County), 1; Pilgrim Creek (10 miles east of Broadus), 1; Piney Buttes, 1; Powderville (Powder River County), 6; Pryor Mountains (Car- bon County), 1; Roy (20 miles northeast, Fergus County), 1; Terry, 1; Tilyou Ranch (26 miles above mouth of Yellowstone River), 3; Wibaux (17 miles south and 17 miles west), 11. Nebraska: Antioch (Sheridan County), 2;' Beaver City, 1; Birdwood Creek (Lincoln County), p.; Blue River (near head, Hamilton County), 1; Calla- way, 1; Cody (Cherry County), 1; Eustis (Frontier County), 1; Gavin Custer County), 1 ; '^ Gothenberg, 1; Grand Island, 1;* Hackberry Lake (Cherry County), 2;^ Homerville (Gosper County), 1; Kelso (Hooker County), 2;' Kennedy (Cherry County), 8; Myrtle (Lincoln County), 1; Niobrara River (Cherry and Sheridan Counties), 2; North Platte, 6; O'Fal- lons Bluff (Lincoln County), 1; Sidney, 1; Valentine, 21. North Dakota: Fort Clark (Oliver County), 4; Glen UUin (Morton County), 6; Heart River (at head), 1; Mandan, 2; Mikkelson (Billings County), 1; Oakdale (Dunn County), 2; Sentinel Butte (Valley County), 2. South Dakota: Ai-dmore (Fall River County), 1; Buffalo Gap (Custer County), 2; Buffalo Valley (Stanley County), I; Bull Springs (near Custer), 10;" Custer, 21:'" Diamond S Ranch (near Rapid City), 1;* Elk Mountain (Custer County), 1; Minichaduza River (Todd County), 1; Pactola (Pen- nington County), 1; Pine Ridge Agency (Shannon County), 1; Spring Creek (Custer County), 1." Wyoming: Bear Lodge Mountains (Crook County), 1; Casper, 4; Cassa (Platte County), 1; Cheyenne, 13; Chugwater (Platte County), 3;* Douglas, 3; Fort Laramie, 1; Fort Russell (Laramie County), 1; Islay (Laramie County), 1; Medicine Bow Mountains, 1; Moorcroft (Crook County), 6; Newcastle (and 25 miles southwest), 3; Pine Bluffs (Laramie County), 3; Spoon Butte (Goshen County), J; Sundance, 1. CITELLUS TRIDECEMLINEATUS ALLENI (Mebeiam) Bighorn Stetpei) Gkound Sqxjibeel Spermophilus tridecemlineatus alleni Merriam, Biol. Soc. Wash. Proc. 12: 71, Mar. 24, 1898. [Citellus tridecimlineatus'] alleni Trouessart, Cat. Mamm., Sup., p. 341, 1904. Type. — Collected near head of Canyon Creek, west slope of Big- horn Mountains, Wyo. (altitude 8,000 feet), September 11, 1893, by Vernon Bailey; male adult, skin and skull, no. 56050, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 4383). ^ Colorado Mus. Nat. Hist. ' E. R. Warren collection. '' Univ. Michigan Mus. Zool. ^ Kansas Univ. Mus. Nat. Hist. •Cleveland Mus. Nat. Hist. «Amer. Mus. Nat. Hist. 1938] REVISION OF THE GROUND SQUIRRELS 115 Range. — The Bighorn Mountains and Bighorn Basin, Wyo. ; south to head of Red Canyon, near Miners Delight, Fremont County, and west to New Fork of Green River (fig, 9). Reported also from Franks Butte, near head of Sage Creek, Park County, Wyo. Zonal range: Transition. External characters — Similar in coloration to C. t. tridecemline- atus but slightly paler and much smaller; size of G. t. 'parvus but much darker. Cranial characters. — Skull smaller than that of tridecemlineatus or C. t. pallidus; similar to that of parvus but relatively longer, with smaller audital bullae and much longer nasals. Color. — Summer pelage (September) : Dark dorsal stripes mummy brown ; light spots and stripes grayish white ; nose and front of face cinnamon buff ; sides of face pinkish buff, washed with fuscous ; front feet pinkish buff; hind feet tilleul buff, the thighs cinnamon buff, washed with snuff brown; tail above, like the back at base, shading to fuscous black on terminal half, edged with tilleul buff or buffy white; tail beneath, cinnamon or pinkish cinnamon, overlaid and edged with buffy white and fuscous black; under parts and lower sides soiled whitish, washed with pinkish buff. Measurements. — Average of 3 adults (1 male, 2 females) from Bighorn Moun- tains and Bighorn Basin: Total length, 206.3 (203-211) ; tail vertebrae, 74 (73- 75) ; hind foot, 31 (30-32). Skull: Average of 3 adults (1 male, 2 females) from same localities: Greatest length, 36.4 (35.8-36.8) ; palatilar length, 16.4 (;16.2-16.5) ; zygomatic breadth, 19.9 (19.5-20.1) ; cranial breadth, 16 (16-16.1) ; interorbital breadth, 7.5 (7.1-7.7) ; postorbital constriction, 11.3 (10.8-11.6) ; length of nasals, 13.2 (12-14.5) ; maxillary tooth row, 6.6 (6.4-6.8). Remarks. — The Bighorn ground squirrel is an inhabitant of moun- tains and foothills, and is decidedly darker than the races living on the plains. The limits of its range are not well knoAvn. Specimens examined. — Total number, 6, as follows: Wyoming: Bighorn Basin (head of Kirby Creek, Hot Springs County), 1; Big- horn Mountains (west slope, near head of Canyon Creek), 2 ; Miners Delight (near head of Twin Creek, Fremont County), 1; New Fork of Green River (Lander Road), 2. CITELLUS TRIDECEMLINEATUS HOLLISTERI Bailet Hor.LisTEB's Striped Ground Sqihrrel Citellus tridecemlineatus hoUisteri Bailev, Biol. Soc. Wash. Proc. 26: 131, May 21, 1913. Type. — Collected in Elk Valley, Mescalero Indian Reservation, Sacramento Mountains, N. Mex. (8,000 feet altitude), September 11, 1902, by Vernon Bailey; female adult, skin and skull, no. 119025, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 7963). Range. — Sacramento Mountains, N. Mex., and mountain valleys of northeastern New Mexico; western limits of range not known (fig. 9). Zonal range: Transition. External characters. — Similar to C. t. alleni, but dark dorsal stripes slightly more reddish and light stripes tinged with buff, the median pair of light stripes usually continuous ; hind feet washed with buff. Cranial characters. — Skull similar to that of alleni., but with heavier and more widely spreading zygomata; larger than that of C. t, parvus. 116 NORTH AMERICAN FAUNA [No. 56 Color. — Summer 'pelage (September) : Dark dorsal stripes chest- nut brown; crown same color mottled with whitish spots; a broad whitish or buffy eye ring; front of face tawny olive; sides of nose pinkish buff; light dorsal stripes and spots grayish wliite, faintly tinged with buff; front legs and feet cinnamon buff; hind legs cin- namon; hind feet dull white, washed with buff; tail (above and below) chestnut brown at base, becoming black on distal half, over- laid with tilleul buff; under parts and sides pinkish buff or pale cinnamon buff. Measurements. — Average of 5 adult females from type locality: Total length, 211.2 (200-232) ; tail vertebrae, 71.8 (60-85) ; hind foot, 30.7 (30-32). Skull: Average of 4 adult females: Greatest length, 36.1 (35-37.4) ; palatUar length, 16.7 (16-17) ; zygomatic breadth, 20.7 (19.3-21.7) ; cranial breadth, 15.9 (15.3- 16.4) : interorbital breadth, 7.3 (6.5-7.8) ; postorbital constriction, 11.6 (11.2- 12.2) ; length of nasals, 13.2 (12.8-13.8) ; maxiUary tooth row, 6 (5.9-6.2). Bemarks. — This race seems to have a discontinuous range; de- scribed from the Sacramento Mountains, southern New Mexico, it proves to occupy, also, the mountain valleys in the northeastern part of the State north nearly or quite to the Colorado line, where it inter- grades with 0. t. arenicola of the plains region to the eastward. The specimens from this region have the dark dorsal stripes more brown- ish (less reddish) than in the typical series. Further collecting in central New Mexico may result in partly connecting this range. Although very similar in external appearance to alleni,, of the Big- horn Mountains, Wyo., the range of holUsten is separated from the range of that form by a wide area in western Colorado mainly occupied by parvus. Bailey (1931, p. 119) has referred the specimens from Moreno Valley to alleni, on the strength of their close resemblance to that race in color; however, the skulls of these New Mexico specimens agree closely with those of hollisteri and differ from those of alleni in heavier build and more widely spreading zygomata. It seems preferable, therefore, by reason of their proximity to the type region of hollisteH., to refer them to that race. Specimens exannin£d. — Total number, 17, as follows : New Mexico: Cimarron (35 miles northwest), 1; Las Vegas (12 miles north), 1; Maxwell, 1;" Mescalero Reservation (Elk VaUey, Sacramento Moun- tains), 7; Mora (10 miles south), 2; Moreno Valley (Colfax County), 5. CITELLUS TRIDECEMLINEATUS MONTIOOLA HowEiJ. Aeizona Stkiped Geounb Squieeel Citellus tridecemlineatus mcnticola Howell, Biol. Soc. Wash. Proc. 41: 214, Dec. 18, 1928. Type. — Collected at Marsh Lake, Wliite Mountains, Ariz. (9,000 feet altitude), June 15, 1915, by Edward A. Goldman; male adult, skin and skull, no. 209255, U. S. Natl. Mus. (Biological Survey col- lection) (orig. no. 22616). Range. — Known only from the type locality (fig. 9). Zonal range: Transition. External characters. — Similar to C. t. alleni but upper parts slightly and under side of tail decidedly more reddish. Similar to "Reading (Pennsylvania) Public Mus, 1938] REVISION OF THE GROUND SQUIRRELS WJ C. t. parvus^ but larger ; coloration of upper parts and under side of tail darker; under parts more buffy (less whitish). Compared with G. t. hollisteri: Upper parts paler, the light dorsal stripes more whitish (less buffy) ; under side of tail more reddish. Cranial characters. — Skull similar to that of hollisteri^ but nasals shorter; decidedly larger than that of 2)arvus^ but with relatively smaller molars; similar to that of alleni but with heavier and more spreading zygomata. Color. — Summer pelage (June 15) : Dark dorsal stripes chestnut brown; light stripes and spots, and eye ring, creamy white; front feet pinkish buff; hind feet cartridge buff, the thighs pinkish cin- namon or mikado brown; tail above, pinkish cinnamon on proximal third, the remainder fuscous black, broadly edged with cartridge buff (the basal portion of the hairs likewise cartridge buff) ; tail beneath, russet, bordered with fuscous black and tipped with car- tridge buff; under parts and lower sides cartridge buff. Measuremeiits. — Average of 7 adults (4 males, 3 females) from type locality: Total length, 221.7 (214-227) ; tail vertebrae, 78 (70-81) ; hind foot, 30.4 (29-32). »S7.w 7?.- Average of 4 adult males: Greatest length, 37 (37-37.1); palatilar length, 17.3 (17-17.5) zygomatic breadth, 21.4 (21.1-21.7) ; cranial breadth, 16.6 (16.3-17) ; interorbital breadth, 7.8 (7.3-8) ; postorbital constric- tion, 11.7 (11.3-12.3) ; length of nasals, 12.7 (12.5-13) ; maxillary tooth row, 5.9 (5.7-6.1). Average of 3 adult females: Greatest length, 35.8 (35-36.1); palatilar length, 16 (15.5-16.5) ; zygomatic breadth, 20 (one specimen) ; cranial breadth, 15.9 (15.7-16.4) ; interorbital breadth, 7.2 (7.1-7.3) ; postorbital constriction, 12 (11.7-12.2) ; length of nasals, 12.3 (11.8-12.8) ; maxillary tooth row, (5.6-6.2). Remarks. — This race is similar to alleni of the Bighorn Moun- tains, Wyo. ; it resembles, also, hollisteri of eastern New Mexico, but is somewhat paler and differs in the color of the under side of the tail. Typical specimens are known only from the higher parts of the White Mountains, Ariz.; specimens from Springerville, at the base of the mountains and from the Datil Mountains, N. Mex., agree with parvus in the coloration of the tail and in skull characters, but are about as dark as typical monticola., thus indicating intergrada- tion between these forms. Specimens examined. — Total number, 7, from Marsh Lake, Wliite Mountains, Ariz. CITELLUS TRIDECEMLINEATUS PARVUS (Allehst) Least Striped GRor?7D Sqtjibkel Spcrmophilus trideccmlineatus parvus Allen, Amer. Mus. Nat. Hist. Bull. 7: 337, Nov. 8, 1895. [Citellus tridecimlhieatus] parvus Trouessart, Cat. Mamm., Sup., p. 341, 1904. Ty/^e.— Collected at Kennedy's Hole, Uncompahgre Indian Reser- vation (20 miles northeast of Ouray, Uintah County), Utah, May 2, 1895, by W. W. Granger; male adult, skin and skull, no. W^, Amer. Mus. Nat. Hist. (ori<2^. no. 537). Range. — Uncompahgre Plateau, eastern Utah and desert regions of southwestern Wyoming, northwestern and south-central Colorado, and west-central New Mexico ; north to Natrona County, AVyo. ; east to Independent Kock, Wyo., south to St. Augustine Plains, N. Mex.; and west to Springerville, Ariz. (fig. 9). Zonal range: Upper Sonoran. llg NORTH AMERICAN FAUNA [No. 56 External characters. — Similar to G. t. arenicola but much smaller and slightly darker ; median pair of light dorsal stripes more or less broken into spots; tail not reddish beneath. Compared with G. t. ■pallidus: Size much smaller and coloration more reddish. Cranial characters. — Skull similar to that of C. t. alleni but slightly smaller and relatively broader, with shorter nasals and larger audital bullae; decidedly smaller than those of arenicola and pallidus. Color. — Winter pelage (type, May 2) : Front of face dull pinkish buff ; top of head sayal brown, mottled with grayish white ; eye ring buff'y white; dark dorsal stripes walnut brown; light stripes and spots creamy white; sides of head and neck and front feet washed with pinkish buff; hind feet dull whitish; tail above and below, pinkish cinnamon, shading to fuscous on distal half, overlaid with grayish white; under parts white. Summer pelage (Bitter Creek, Wyo., August) : Dark dorsal stripes snuff brown ; tail heavily over- laid on both surfaces with cinnamon buff. Measurements. — Average of 5 adult males from Utah (the type and^ others from Ouray) : Total length, 189 (170-202) ; tail vertebrae, 71 (69-72) ; hind foot, 28 (27-29), Average of 12 adults from Bitter Creek, Wyo., and Snake River, Colo.: 204.6 (189-228) ; tail vertebrae, 76.7 (65-87) ; hind foot, 32.9 (28-31). Skull: Average of 4 adult males (type from Utah ; 2 from Bitter Creek, Wyo.; one from Snake River, Colo.) ; Greatest length, 35.3 (34.6-36.2) ; palatilar length, 15.5; zygomatic breadth, 20.2 (19.7-21); cranial breadth, 16.7 (16.4-17.3); in- terorbital breadth, 7.1 (6.9-7.3) ; postorbital constriction, 11.4 (11.1-11.7) ; length of nasals, 11.7 (10.5-12.7) ; maxillary tooth row, 6.2 (5.9-6.4). Average of 4 adult females (Ouray, Utah, Bitter Creek, Wyo., and Routt County, Colo.) : Greatest length, 33.9 (33.2-34.3) ; palatilar length, 14.9 (14.5-15.5) ; zygomatic breadth, 19.4 (19.1-19.7) ; cranial breadth, 16.1 (15.8-16.4) ; interorbital breadth, 7.1 (7-7.2) ; postorbital constriction, 11.2 (11-11.5) ; length of nasals, 10.5 (10-11) ; maxillary tooth row, 6.2 (6-6.4). Weight. — One female weighed 6 ounces. Remarks. — This subspecies is the smallest of the races of G. tride- cemlineatus and is about as pale as arenicola from western Kansas. Its range is imperfectly known at present and appears to be discon- tinuous. A good series from Bitter Creek, southwestern Wyoming, appears to be typical and a few specimens from northwestern Colo- rado are also referred to this race, although they average darker; and those from Lay, Rangely, and Mud Springs might on the basis of color be referred to alleni. Their skulls, however, are small, like those of parvus. A series from the San Luis Valley, southern Colorado, is provisionally referred to parvus, although they show some color variations that may necessitate their separation when it is possible to compare them with a good series of topotypes. Inter- gradation with G. t. monticola of southern Arizona is indicated by small series from Datil Mountains, N. Mex., and Springerville, Ariz. ; with alleni by specimens from New Fork of Green River, Wyo., and with pallidus by specimens from Casper, Wyo. (referred to pallidus). Specimens examined. — Total number, 69, as follows: Arizona: Springerville, 4. Colorado: Antonito, 2; Axial Basin (12 miles southeast of Lay), 2; Escalante Hills (Moffat County), 1; Fort Garland, 3; Medano Ranch (Alamosa County), 2;" Mosca (Alamosa County), 1;" Muddy Creek (Huerfano County), 1;"; Mud Springs (Garfield County, 30 miles southeast of Meeker), 4;" Rangely (Rio Blanco County), 2; San Acacio (Costilla County), 3;" San Luis Lakes (Alamosa County), 1;" Snake River (Mo(- 1938] REVISION OF THE GROUND SQUIRRELS HQ fat County), 5;"" Two Bar Spring (western Moffatt County), 1;" West- cliff e (Custer County), 7. New Mexico: Datil Mountains (12 miles northwest of Datil), 2; St. Augustine Plains (near Monica Spring), 2. Utah: Fruitland, 3;" Ouray (12 miles southwest), 4;" Uncompahgre Indian Reservation, 4." ^^ Wyoming: Big Sandy (Sublette County), 1; Big Sandy Creek (Lander Road), 1; Bitter Creek (Kinney Ranch, Sweetwater County), 9;" Green River, 1; Independent Rock (mouth of Dry Creek, Natrona County), 1; Myersville (Fremont County), 1; Sun (Natrona County), 1. CITELLUS MEXICANUS (Eexlb35En) [Synonymy under subspecies] Specific characters. — Size large; hind foot 38-51 mm; tail about 40 percent of the total length ; skull length, 41-52.5 mm. Skull sim- ilar to that of C. tridecemlineatus but considerably larger ; brain case less elongate, more nearly square ; zygomata more widely expanded ; audital bullae large and smoothly rounded. Ears broad and low, rising 3-5 mm above crown. Coloration of upper parts varying from wood brown or buffy brown to sayal brown or snuff brown, marked with squarish white spots arranged in linear rows, usually nine in number, the spots sometimes partly confluent, at other times more or less obsolete; head buffy brown or wood brown, sprinkled with white, the nose clay color or cinnamon buff; feet, sides, and under parts white to pinkish buff; tail above, mixed fuscous and grayish or buffy white; tail beneath, avellaneous to cinnamon buff, more or less obscured by grayish or buffy white. CITELLUS MEXICANUS MEXICANUS (Erxleben) Mesican Ground Squirkex (Pis. 25, C; 30, C) [8ciuru8'\ mexicanus Erxleben, Syst. Regni Anim. 1 : 428, 1777. Citillus mexicanus Lichtensteiu, Darstel. Saugt., plate 31 (and accompanying text), 1827-1834. Spermophilus mexicanus Wagner, Schreber's Siiugt., Sup., 3: 250, 1843. Otospermophilus mexicanus Brandt, CI. Phys.-Math. Acad. Sci. St. Petersbourg Bull. 2 : 379, 1844. Citellus mexicanus Merriam, Biol. Soc. Wash. Proc. 16 : 80, 1903. Type. — None designated ; type locality fixed at Toluca, Mexico, bv Mearns (1896, p. 443). Range. — Central Mexico, from northern Jalisco and Guanajuato south to southern Puebla (fig. 10). Zoiuil range: Lower Sonoran. External characters. — Size large; hind foot, 46.5-51 mm; skull length, 45.3-52.5; coloration averaging darker, with more buffy sides and under parts than in C. m. parvidens. Cranial characters. — Skull similar to. that of G. tHdecemlineatus tridecemlineatus but much larger; brain case relatively broader; audital bullae larger and more inflated. Color. — Upper parts buffy brown, sayal brown, or snuff brown, the dorsum covered with numerous squarish white spots arranged in nine linear rows (sometimes with indications of another pair of lines ^ E. R. Warron collection. « Colo. Mus. Nat. Hist. " Amer. Mus. Nat. Hist, i"^ Field Mus. Nat. Hist. " Carnegie Mus. 120 NORTH AMERICAN FAUNA [No. 56 on lower sides), the middle row usually somewhat narrower than the others; the lines sometimes irregular and broken in middle of back, and spots sometimes confluent on some of the rows ; head buff y brown, with whitish tips to some of the hairs; nose and front of face cinnamon buff or clay color; eye ring white; feet pinkish buff or cartridge buff; tail above, mixed fuscous and buffy white, with some of the body color near the base ; tail be- neath, avellaneous to cinnamon buff, bor- dered with fuscous and edged with buffy white. Measurements. — ^Aver- age of 10 adults and sub- adults from central Mex- ico (states of Hidalgo, Queretaro, Guanajuato, and Mexico): Total length, 349.6 (322-380) ; tail vertebrae, 144.6 (124r- 166) ; hind foot, 48.4 (46.5-51). Skull: Aver- age of 13 adults (6 males, 7 females) from Quere- taro, Guanajuato, and Ja- lisco : Greatest length, 49 (45.3-52.5) ; palatilar length, 23.5 (22-24.2) ; zygomatic breadth, 28.9 (27-30.3); cranial breadth, 20.4 (19.3-21.1) ; interorbital breadth, 10.4 (9.6-11.1) ; postorbital constriction, 14 (13.2- 14.8) ; length of nasals, 17.8 (15.8-20.1); maxillary tooth row, 9.8 (9.3-10.5). Remarks. — This strikingly marked ground squirrel was one of the first North American species to be recognized, having been named by Erxle- FiGOKE 10. — Distribution of the subspecies of Citellus mexi- l-\pn in 1777 Tt tq pnm- canus; 1, V. m. parvidens; 2, C. m. mexicanus. ' * T , ? ^ \ mon on the tableland of central Mexico, occupying an area lying mainly south of the range of 0. spilosoma. It resembles this species only slightly, being much larger and more heavily spotted. It varies considerably in color; the extremes of coloration might be designated as a brovvn phase and a drab or olivaceous phase, but there are several intermediate shades in any large series of specimens. Specimens examined. — Total number, 31, as follows: Guanajuato : Celaya, 1 ; Silao, 3 ; Irolo, 1 ; Marques, 1. Jalisco: Atemajac, 7; Lagos, 2; Zapotlan, 6. Mexico: Tlalpam (Federal District), 4. Puebla: Atlixco, 1 ; San Andres Chalchicomula, 1 ; San Martin, 1. Queretaro: Tequisquiapan, 2. Tlaxcala: Huamantla, 1. 1938] REVISION OF THE GROUND SQUIRRELS 121 CITELLUS MEXICANUS PARVIDENS (Meaens) Rio Grande Ground Sqxjibbei, Spermophilus mexicanus parvidens Mearns, U. S. Natl. Mus. Proc. 18: 443, May 23, 1896 (advance sheets issued, Mar. 25, 1896). [Citelliis mexicanus^ parvidens Elliot, Field Columb. Mus., Zool. Ser. 4: 146, 1904. Type. — Collected at Fort Clark, Kinney County, Tex., March 21, 1893, by E. A. Mearns; male adult, skin and skull, no. 63073, U. S. Natl. Mus. (orig. no. 2312). Range. — Northeastern Mexico, ^Yestern Texas, and southeastern New Mexico ; north to Eoswell, N, Mex. and Borden County, Tex. ; east to Austin and Rockport, Tex.; south to southern Tamaulipas; west to central Coahuila and extreme western Texas (El Paso) (fig. 10). Zonal range: Lower Sonoran. External characters. — Similar to C. m. mexicanus but decidedly smaller; coloration averaging paler, with less buff on under parts and hind legs. Cranial characters. — Skull similar to that of mexicanus but decidedly smaller. Color. — Upper parts varying from wood brown to sayal brown or snuff brown, with nine usually distinct linear rows of large white spots; head same color as back, flecked with white; nose patcli cin- namon buff; eye ring white ; sides of face and neck smoke gray; sides of body and under parts creamy white or cartridge buff; hind legs cinnamon buff to cartridge buff; feet pinliish buff or buffy white; tail above, mixed fuscous and buffy white; tail beneath, cartridge buff or pinkish buff, more or less overlaid with buffy white. Measurements. — Average of 12 ndults from type locality: Total length, 300.S (280-313); tail vertebrae, 118.3 (110-126); hind foot, 40.9 (38-43). Skull: Average of 17 adults (9 males, 8 females) from type locality: Greatest length, 43 (41.1-44.8) ; palatilar length, 20.7 (10.5-22) ; zygomatic breadth, 25.3 (23.5-27.1) ; cranial breadth, 18.6 (17.S-19.5) ; interorbital breadth, 9.4 (8.2- 10.5) ; postorbital constriction, 12.7 (12-14.6) ; length of nasals, 15.1 (13.5- 16.2) ; maxillary tooth row, 8 (7.3-8.9). Remarhs. — This northern race of mexicanus is distinctly larger than the typical race, and, like it, shows a great amount of variation in color; the majority of specimens of parvidens are paler than mex- icanus but some in the brown phase are not appreciably different in color. Although actual integradation with mexicanus is not shown by the material in hand, it seems highly probable that additional col- lecting in Mexico, particularly in &an Luis Potosi, will result in the discovery of intergrades. Specimens examined. — Total number, 225, as follows: Coahuila: Las Vacas, 1; Monclova, 1; Sabinas, 1; Saltillo, 8. New Mexico: Carlsbad, 2; Roswell, 3. Nuevo Leon: Montemorelos, 1; Pesqueria Grande (probably near Monterey), 1; Santa Catarina, 1. Tamaulipas: Bagdad, 3; Camargo, 2; Mier, 5; Nuevo Laredo, 1; Reynosa, 1; Victoria, 1. Texas: Adams (Pecos County), 2; Alice, 1; Alpine, 1; Altuda (Brewster County), 7 ; Beeviile, 1 ; Big Spring, 2 ; Brownsville, 20 ; Cameron County, 7 ; Carrizo Springs, 2 ; Colorado, 4 ; Comstock, 3 ; Concho County, 1 ; Corpus Christi, 9;" Cotulla, 3; Del Rio, 3; Devils River (at mouth), 2; Eagle " Three in Field Mus. Nat. Hist. 122 NORTH AMERICAN FAUNA [No. 56 Pass, 3; East Painted Cave (near moutli of Pecos River), 1; Fort Clark (Kinney County), 33; Fort Lancaster (Crockett County), 6; Fort Stockton (25 miles west), 2; Juno (Val Verde County), 1; La Hacienda (10 miles southeast of Hidalgo), 1; Langtry (Val Verde County), 15; Laredo, 5; Lomita Ranch (Hidalgo County), 2; Lozier (Terrell County), 1; Marathon, 1; Mason, 1; Monahans (Ward County), 4; Norias (Kenedy County), 2; ^*° Pecos, 4; Port Isabel, 14:^^ Rio Grande City, 5; Rock Springs (10 miles west), 1; Rockport, 1;" Samuels (Val Verde County), 4; San Angelo 1; San Diego, 5; Sarita (Kenedy County), 3;"" Sheffield (Pecos County), 3; Stanton, 3; Sycamore Creek (Val Verde County), 3. CITELLUS SPILOSOMA GROUP CITELLUS SPILOSOMA (BENNETtT) [Synonymy under subspecies] Specific characters. — Size small to medium; hind foot, 28-38 mm; tail, 55-88 ; skull length, 34.1-42.7. Skull similar to that of C. tri- decemlineatus., but relatively shorter and broader, especially the rostrum and interorbital region ; audital bullae much larger. Color. — Upper parts drab, cinnamon drab, avellaneous, smoke gray, fawn, wood brown, snuff brown, or verona brown, more or less spotted with squarish white spots; tail above, usually similar to the back, darkened at the tip with fuscous black; tail beneath, pinkish buff, pinkish cinnamon, vinaceous cinnamon, or cinnamon buff. CITELLUS SPILOSOMA SPILOSOMA (Bennett) Bennett's Spottbh) Ground Sqtjirebl (Pis. 25, A; 30, A) Spermophiliis spilosoma Bennett, Zool. Soc. London Proc. 1833 : 40. Citellus spilosoma Allen, Amer. Mus. Nat. Hist. Bull. 20 : 209, 1904. Lectotype (Thomas, 1927, p. 548).— No. 53.8.29.5, British Museum; male, skin (without skull), from an unknown locality; in the absence of any definite information relative to the type, the type locality is hereby fixed at Durango, Durango.^^ Range. — Central Mexico, from Durango City south to Aguas- calientes; east to San Luis Potosi (city) (fig. 11). Zonal range: Lower Sonoran. External characters. — Size large ; tail long, with considerable black at distal end; dorsal spotting rather fine, becoming obsolete on the anterior part of the body. Cranial characters. — Skull similar in shape to that of C. mexicanus mexicanus but much smaller; similar to that of C. tridecemlineatus texensis but with broader brain case and larger audital bullae. Color. — (Jesus Maria, San Luis Potosi, Sept. 10) : Upper parts fawn color, moderately speckled, chiefly on hinder back, with small squarish spots of white; eye ring buffy white; sides of faca neck, and shoulders washed with smoke gray ; front feet pinkish buff ; hind feet cartridge buff • tail above, vinaceous fawn, the hairs on the distal half with a broad subterminal band of black, tipped with buffy white; tail beneath, vinaceous cinnamon, more or less obscured by black and edged with buffy white; under parts white, tinged with pale buff. « Field Mus. Nat. Hist. isaAcad. Nat. Sci. Philadelphia, "See remarks, p. 123. 1938] REVISION OF THE GROUND SQUIRRELS 123 A specimen from Durango, Durango, June 27 (said to agree closely with the type) is slightly more reddish above than this description, the general tone about vinaceous fawn. Measurements. — Average of 11 adults from Aguascalientes and San Luis Potosi (Jesus Maria and Hacienda La Parada) : Total length, 238.4 (230-250) ; tail vertebrae, 77.7 (71-88); hind foot, 35.8 (34-37). Skull: Average of 11 adults (2 males, 9 females) from San Luis Potosi and Zacatecas : Greatest length, 40.9 (39.3-42.7) ; 1^ J J \ n palatilar length, 1S.8 '■^•"-ll, i "C K""^ (18.2-19.8) ; zygomatic . ^ >. 1 breadth 24.5 (23-26.6) ; cranial breadth, 18.6 (17.8-20) ; interorbital breadth, 8.8 (8-10) ; post- orbital constriction, 14.2 (13.1-15.9) ; length of na- sals, 14.2 (13.7-15.2) ; maxillary tooth row, 7.6 (7-8). Re^narJcs. — Origi- nally described in 1833 from an unknown lo- cality, this species has never been fully char- acterized and it seems impossible to discover the exact source of the type specimens. They were stated by the de- scriber to have been obtained in "that part of California which adjoins to Mexico." Baird (1857, p. 322) states: "this species was first described from specimens col- lected on the western coast of Mexico", but does not give the source of his informa- tion. However, since the species is not known to occur to the westward of the Si- erra Madre in Mexico, this statement cannot be taken literally. At the time the species was described (1833), few expeditions had been made to the region where it lives. Capt. Beechey's expedition, however, remained at San Bias, on the coast of Tepic, from December 8, 1827, to February (?), 1828, and Mr. Lay, the naturalist of the expedition, "visited and remained for a long time at Tepic, 54 miles from San Bias, inland" (Hooker and Arnott, 1841, p. 1), and it seems not at all improbable that the type specimens may have been obtained by this expedition. In order to settle, if possible, the identity of typical spilosoma, several specimens of this species from central Mexico and several from Figure 11. — Distribution of Citellus perotcnsis and of the subspecies of C. spUosoma: 1, O. s. obsoletus ; 2, C. 8. pratensis; 3, C. s. cruptospllotus ; 4, C. a. major; 5, G. s. canescens; 6, C. s. annectens ; 7, C. s. pallescens ; 8, 0. 8. spiloaovia; 9, C. perotensis. 124 NORTH AMERICAN FAUNA [No. 56 southern Arizona {C. s. canescens) Avere forwarded to the late Old- field Thomas, at the British Museum, who kindly compared them with the cotypes in that institution. He wrote as follows : After a careful comparison it appears to me that the large form from TDurango], central Mexico (No. 9459S, U. S. N. M.) most nearly agrees with the type of spilosoma, though unfortunately the latter has no skull to give an abso- lute indication of size ; the feet, however, would appear to be quite as large as in your specimen. The only difference is that our specimens are of a rather stronger cinnamon colour anteriorly, especially on the crown, less greyish. This decision will involve no shifting of names, since the other de- scribed forms in the group are all recognizably different from this race. Specimens examined. — Total number, 39, as follows: Aguascalientes : Chicalote, 14. Durango: Durango, 13. San Luis Potosi: Jesus Maria, 2. Zacatecas: Berriozabal, 10. CITELLUS SPILOSOMA PALLESCENS Howell P^u.LiD Spottjcd Geound Squireel Citellus spilosoma pallescens Howell, Biol. Soc. Wash. Proc. 41 : 212, Dec. 18, 1928. Type. — Collected at La Ventura, Coahuila, August 10, 1896, by E. W. Nelson and E. A. Goldman; male adult, skin and skull, no. 79535, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 10016). Range. — North-central Mexico from southern Chihuahua (Santa Rosalia) southward to San Luis Potosi and eastward to southern Nuevo Leon (Doctor Arroyo) (fig. 11) . Zonal range: Lower Sonoran. External characters. — Similar to G. s. spilosoma., but paler. Com- pared with G. s. canescens : Size larger ; tail longer, with more black on distal half ; dorsal spotting finer. Granial characters. — Skull similar to that of spilosoma but aver- aging smaller, with shorter, broader rostrum and nasals ; larger than that of G. s. canescens, with longer, narrower rostrum. Golor. — (August specimens, topotypes) : Upper parts wood brown or drab, finely speckled, chiefly on hinder back, with white ; tail above, light pinkish cinnamon on proximal half, the distal half bordered with fuscous black and edged with buffy white ; tail beneath, pinkish buff, bordered with fuscous black and buffy white; otherwise as in spilosoma. Measurements. — Average of 12 adults from La Ventura and Carneros, Coa- huila: Total length, 242.6 (232-253); tail vertebrae, 84.8 (76-92); hind foot, 35.7 (34.5-37). Skttll: Average of 10 adults from La Ventura: Greatest length, 40.1 (38.9-41.1) ; palatilar length, 17.9 (17.2-18.5) : zygomatic breadth, 23.8 (22.9-24.5) ; cranial breadth, 18.6 (18.2-19) ; interorbital breadth, 8.4 (7.8-8.9) ; postorbital constriction, 14 (12.8-15.1; length of nasals, 18.6 (13-14.5) ; maxil- lary tooth row, 7.5 (7.1-8.1). Bemarks. — This pale race, occupying the plains of north-central Mexico, is most nearly related to spilosoma. It intergrades with both spilosoma and canescens. A large series from Santa Eosalia, Chihua- hua, is nearest to pallescens., but shows approach to canescens in the coarser spotting of some individuals and in the size and shape of some of the skulls. 19381 REVISION OF THE GROUND SQUIRRELS 125 Specimens examined. — Total number, 75, as follows : Chihuahua: Escalon, 4; Santa Rosalia, 20. Coahuila: Carneros, 6; Jaral, l;"" La Ventura, 17; Torreon, 6. Nuevo Leon : Doctor Arroyo, 2. San Luis Potosi: Hacienda La Parada (about 20 miles northwest of San Luis Potosi), 17; San Luis Potosi, 1. Zacatecas: Caiiitas, 1. CITELLUS SPILOSOMA CANESCENS (Mebbiam) Apache Spotted Geoxjnd Sqttieeel (PI. 5) Spermophilus canescens Merriam, North Amer. Fauna 4 : 38, Oct. 8, 1S90. Spermophilus spilosoma macros irilot us Merriam, Ibid., p. 38, (Oracle, Ariz.). Anisonyx (.Xerospermophilns) canescens Allen, Amer. Mus. Nat. Hist. Bull. 7: 239, 1895. Anisonyx {Xero spermophilus) spilosoma macrospilotus Allen, loc. cit., p. 239, 1895. [Spermophilus spilosoma] microspilotus Elliot, Field Columb. Mus. Pub. Zool. Ser. 2: 96, 1901 (accidental renaming of macrospilotus). Spermophilus spilosoma arens Bailey, Biol. Soc. Wash. Proc. 15 : 118, 1902 (El Paso, Tex.). . Citellus spilosoma microspilotus Elliot, Field Columb. Mus. Pub., Zool. Ser. 4 : 144, 145, 1904. Citellus spilosoma macrospilotus Elliot, Field Columb. Mus. Pub., Zool. Ser. 6: 99, 1905. Citellus spilosoma canescens Bailey, North Amer. Fauna 53 : 109, 1931. Type. — Collected at Will cox, Cochise County, Ariz., November 16, 1889, by Vernon Bailey; male juv,, skin and skull, no. ^-||^^, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 676). Range. — Southeastern Arizona and southwestern New Mexico; south to Chihuahua City, Chihuahua, Mexico ; west to Altar Valley, Ariz.; north to Gila Valley (Pima), Ariz.; east to Deming, N. Mex. and Fort Hancock, Tex. (fig. 11). Zonal range: Lower Sonoran. External characters. — Similar to G . s. pallescens, but smaller, with shorter tail and hind feet; dorsal spots larger, and more numerous on f oreback ; tail with more black on distal portion. Cranial characters. — Skull similar to that of pallescens, but smaller, with shorter, broader rostrum. Color. — Cinnamon phase (January) : Upper parts fawn color, thickly spotted over most of the back with rather large, quadrangular whitish spots, more or less obscured or obsolete on the f oreback; a broad white ring surrounds the eye ; sides of nose whitish ; sides of body washed with pinkish buff; front feet cartridge buff: hind feet, white; tail above, vinaceous fawn, edged with pinkish buff, the hairs on distal half with a subterminal band of fuscous black; tail beneath, cinnamon buff with a narrow band of fuscous black near the tip; under parts white. Worn specimens in spring (April and May) have the tail considerably darker — dull orange cinnamon. D7'ab phase (May) : Upper parts light drab or light cinnamon drab, spotted as in the cinnamon phase ; sides whitish or with a very faint wash of pale ivory yellow. Measurements. — Average of 11 adults from Willcox, Ariz.: Total length, 228.5 (210-247) ; tail vertebrae, 73.8 (07-86) ; hind foot, 32.1 (30-34). Skull: Average of 10 adults (4 males, 6 females) from Willcox and Oracle, Ariz. ; » Field Mus. Nat. Hist. 126 NORTH AMERICAN FAUNA [No. 56 Greatest length, 38.1 (37.5-38.7) ; palatilar length, 17 (16.a-17.5) ; zygomatic breadth, 23.2 (23-23.9) ; cranial breadth, 18.1 (17.6-19.2) ; interorbital breadth, 8.3 (7.5-8.9) ; postorbital constriction, 13.8 (13-14.4) ; length of nasals, 12.8 (11.6-13.5) ; maxillary tooth row, 7.2 (6.5-7.4). Weight. — Two specimens weighed respectively, 81.5 and 93.4 g. Remarks. — The Apache ground squirrel is j-eadily distinguished from the central Mexican forms {(J. s. spilosoma and pallescens) by the larger and more numerous dorsal spots. Specimens from Chihuahua City are typical, but south of that point intergradation with pallescens occurs. Specimens from El Paso and Fort Han- cock, Tex., are intermediate between canescens and C. s. major. The range of this form northward in Ai'izona apparently is limited by the Mogollon Plateau. Specimens examined. — Total number, 125, as follows : Arizona: Buenos Ayres, Altar Valley, 1; Chiricahua Mountains (2 miles south- east of Moore's Ranch), 1;^^ Fort Bowie (Cochise County), 1; Fort Grant (Graham County), 1; Fort Huachuca, 9; Huachuca Mountains, 3;^" La Noria, Santa Cruz River, 1 ; Mowry, Patagonia Mountains, 2 ; Oracle (Pinal County), 6; Pima, 1; Tombstone, 2; Tucson (24 miles southeast), 1; Willcox, 24. Chihuahua : Casas Grande, 4 ; Chihuahua, 15 ; Lake Palomas, 1 ; White Water, Mexican boundary line, 1. New Mexico: Apache (Grant County), 1 ; Deer Creek (Hidalgo County), 2; Dem- ing, 2; Dog Spring (Grant County), 7; Fayvrood (Grant County), 1; Hachita, 3; Mangos Valley (Grant County), 1; Monument 15, Mexican boundary line, 4; Monument 40, Mexican boundary line, 2; SUver City, 2 ; Warren, 6 ; "" Whitmire Pass, Playas Valley, 1. Texas: El Paso, 10; Fort Hancock (El Paso County), 9. CITELLUS SPILOSOMA MAJOR (Merkiam) New Mexico Spotted Geotjnd Squierel SpermopMlus spilosoma major Merriam, North Amer. Fauna 4 : 39, Oct. 8, 1890. Spermophilns spilosoma marginatus Bailey, Biol. Soc. Wash. Proc. 15: 118, 1902 (Alpine, Tex.). [Citellus stnlosoma] major Trouessart, Cat. Slamm., Sup., p. 340, 1904. Type. — Collected at Albuquerque, N. Mex., July 22, 1889, by Ver- non Bailey; female adult, skin and skull; no. Hm, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 225). Range. — Eastern New Mexico, western Texas, western Oklahoma, south Avestern Kansas and southeastern Colorado; north to Adams and Yuma Counties, Colo. ; east to Kinsley, Kans., Woodward, Okla., and Colorado, Tex. ; south to Presidio and Brewster Counties, Tex. ; west to St. Augustine Plains, N. Mex. (fig. 11.) Zonal range: Upper Sonoran. External characters. — Similar to G. s. canescens.^ but hind feet larger; dorsal spots fewer and less distinct. Cranial characters. — Skull similar to that of canescens., but larger, with decidedly longer nasals. Color. — Upper parts varying from light cinnamon-drab or avella- neous to fawn color or mikado brown (in worn specimens), spar- ingly spotted on the back with m.ore or less indistinct white spots; front feet pinkish buff; hind feet buffy white; tail above, usually same color as the back, the hairs on distal portion with a subterminal SI Acad. Nat. Sci. Philadelphia. 2ia Carnegie Mus. 1938] REVISION OF THE GROUND SQUIRRELS 127 band of fuscous; tail beneath, light pinkish cinnamon, pinkish buff, or light vinaceous cinnamon; under parts and sides white, some- times washed with cartridge buff. Measriremcnts. — Average of 8 adults (3 males, 5 females) from Albuquerque and Isleta, N. Mex. : Total length, 231.7 (221-245) ; tail vertebrae, 76.7 (69-80) ; hind foot, 35.2 (34-36). Skull: Average of 10 adult males from New Mexico (Albuquerque, Espaiiola, Capitan Mouutains) and southern Colorado (La Junta, and Las Animas County) : Greatest length, 40.9 (39.7-42.5) ; palatilar length, 18.6 (18-19.5) ; zygomatic breadth, 24.3 (23.5-25.6) ; cranial breadth, 18.9 (17.9-19.9) ; interorbital breadth, 8.6 (8.1-9.1) ; postorbital constriction, 13.7 (12.6-14.8) ; length of nasals, 14.4 (13.5-15.5) ; maxillary tooth row, 7.6 (7-8). Average of 10 adult females from New Mexico (Albuquerque, Espaiiola, Isleta, Carrizozo, Capitan Mountains) ; Greatest length, 40.4 (39-41.5) ; palatilar length, 18.2 (17.5-18.8) ; zygomatic breadth, 24.1 (23.4-24.9) ; cranial breadth, 18.7 (18.1-19.6) ; interorbital breadth, 8.5 (7.8-9.1) ; postorbital con- striction, 14 (13.4-14.5) ; length of nasals, 14.3 (13.2-15.2) ; maxillary tooth row, 7.5 (6.2-8). Remarks. — This wide-ranging form is distinguished from its near- est neighbors chiefly by its large size. The drab phase is compara- tively rare and does not appear in pure form — ^that is, many of the specimens are more or less intermediate between a drab and a cin- namon phase. Two specimens from 8 miles east of Deming, N. Mex., are typical majo?", while several others from Deming are best re- ferred to canescens. The present form passes insensibly into subspecies C. s. obsoletus; most of the specimens from eastern Colorado, north of the Arkansas Valley, are so completely intermediate between the two forms that it is very difficult to say which form they most resemble. The series from Las Animas, Colo., is clearly referable to major., the skulls being even larger than skulls of topotypes from New Mexico. Speci- mens from Tuttle, Wray, and Barr Lake show approach to obsoletus. The series from Alpine, Tex., on which was based the subspecies '"''marginaius'''' of Bailey, averages slightly darker than typical major^ all of them being in the cinnamon phase, but some specimens of the tAvo series are indistinguishable; no difference is apparent in the amount of black flecking on the back, which in both forms is very inconspicuous. Specimen.'^ examined. — Total number, 172, as follows: Colorado: Akron, 1;'* Barr Lake (Adams County), 1;^ Carrizo Creek (Baca County), 1;" Elbert County (between Mattison and Resolis), 1;" Foss- ton (Weld County), 2;** Hugo, 1; La Junta (18 miles south), 2; Lamar, 3;"" Las Animas, 9; Monon (Baca County), 2;^ Regnier (Baca County), 1.'' Kansas : Morton County, 1 ; *^ Kinsley, 1. New Mexico: Alamogordo, 5; Albuquerque, 11; Bear Spring Mountains (north of Magdalena, Socorro County), 4; Cabra Springs (San Miguel County), 1; Capitan Mountains (northwest foothills), 6; Carlsbad ("Eddy"), 7; Car- rizozo, 1; Deming (8 miles east), 2; Espauola, 7; Fort Sumner (8 miles north), 1; Isleta, 4; Lake Valley (Sierra County), 1; Magdalena (10-15 miles southeast), 2; Maxwell. 1;'* Mesilla, 3;*°" Ojo Caliento (northeast of Chloride, Sierra County), 1; Rio Alamosa (15 miles north of 0.jo Cali- ente), 1; Roswell (and 20 and 50 miles north), 17; St. Augustine Plains (Catron County, 12 miles north of Monica Spring), 10; San .Jon (Quay County), 1;** Santa Rosa, 7. 22 Univ. Mich. Mu.s. Zool. « Colorarto Mus. Nat. Hist. ^ E. K. Warren collection. ^ Kansas Univ. Mus. Nat. Hist. *"Acad. Nat. Sci. Philadelphia. '^ State Collf'ge, New Mexico. * Cleveland Mus. Nat. Hist. ■» Reading (Pennsylvania) Public Mus. ]^28 NORTH AMERICAN FAUNA [No. 56 Oklahoma: Woodward, 7. Texas : Alpine, 12 ; Canadian, 1 ; Colorado, 2 ; Lipscomb, 1 ; Mobeetie, 3 ; Mona- bans (Ward County), 15; Miami, 1; Pecos, 4; Presidio County, 1; Toyah- vale (Reeves County), 2; Valentine, 3; Van Horn (Culberson County), 1. CITELLUS SPILOSOMA ANNECTENS (Mekeiam) Padee Island Gkottnd Sqijieeel Spermophilus spilosoma annectens Merriam Biol. Soc. Wasb. Proe. 8 : 132, Dec. 28, 1893. [Gitellns spilosoma] annectens Trouessart, Cat. Mamm., Sup., p. 340, 1904. Type. — Collected at "The Tanks," 12 miles from Point Isabel, Padre Island, Tex., August 24, 1891, by Wm. Lloyd ; male adult, skin and skull, no. Htlti U. S. Natl. Mus. (Biological Survey collection) (orig. no. 694). Range. — Lower Rio Grande Valley, Tex., and Gulf coast section from the mouth of the river north to Nueces River ; Padre and Mus- tang Islands (fig. 11). Zonal range: Lower Sonoran. External characters. — Closely similar in size and coloration to C. s. major. Cranial churacters. — Skull closely similar to that of major, but averaging slightly longer, and slightly broader interorbitally ; with slightly narrower brain case ; audital bullae smaller. Color. — (Worn summer pelage) : Upper parts avellaneous or smoke gray ; dorsal spots large but rather indistinct ; sides white, sometimes washed with cartridge buff; tail above, like the back, shaded on distal portion with fuscous and edged with pale cartridge buff; tail beneath, cinnamon or light pinkish cinnamon; feet light pinkish cinnamon or pinkish buff ; under parts soiled whitish. Measurements. — Average of 6 adults from type locality : Total length, 229 (220-234); tail vertebrae, 64.2 (55-75); hind foot, 35.4 (33-38). SkuU: Average of 7 adults (6 males, 1 female) from tj^e locality: Greatest length, 41 (40.5^1.5) ; palatilar length, 18.1 (17.5-19) ; zygomatic breadth, 23.8 (23.2-24.4) ; cranial breadth, 18 (17.6-18.5) ; interorbital breadth, 9 (8.5-9.3) ; postorbital constriction, 13.1 (12.1-14.1) ; length of nasals, 14.1 (13.4-14.6) ; maxillary tooth row, 13.1 (12.1-14.1). Remarks. — The Padre Island ground squirrel is evidently an off- shoot of major and shows no close relationship to the darker and more finely spotted forms in Mexico. Some form of this species has been reported from various points along the Rio Grande, up as far as the mouth of the Pecos River, but no specimens are available from that part of the valley ; therefore it is uncertain whether or not the range of annectens meets that of major. Specimens examined.- — Total number, 30, as follows: Texas : Mustang Island, 2 ; ^* Norias, 2 ; ^^ Padre Island, 21 ; Rio Grande River (at mouth), 1; Sarita, 4..'^^ CITELLUS SPILOSOMA PRATENSIS (Mereiam) Park Spotted Gbound Squiebel (Pls. 25, B\ 30, B) Spermophilus spilosoma pratensis Merriam, North Amer. Fauna 3 : 55, Sept. 11, 1890. Spermophilus spilosoma obsidianus Merriam, North Amer. Fauna 3 : 56, 1890 (Cedar Belt, northeast of San Francisco Mountain, Ariz.). [Citellus spilosomaJi pratensis Trouessart, Cat. Mamm., Sup., p. 340, 1904. 2»«Acad. Nat. Scl, Philadelphia. 1938] REVISION OF THE GROUND SQUIRRELS 129 Type. — Collected at north base of San Francisco Mountain (pine plateau), Ariz., August 5, 1889, by C. Hart Merriam and Vernon Bailey; female adult, skin and skull, no. mif , U. S. Natl. Mus. (Biological Survey collection) (orig. no. 285). Range. — North-central Arizona, between the Grand Canyon and the Mogollon Plateau; west to Seligman and Aubrey Valley (fig. 11). Zonal range: Upper Sonoran and Transition. External characters. — Similar to C. s. canescens but smaller, with shorter tail and hind feet ; upper parts darker ; dorsal spots smaller ; tail darker, with more black on distal portion. Cranial characters. — Skull similar to that of canescens ., but de- cidedly smaller ; much smaller than that of C. s. major. Color. — General tone of upper parts near snuff brown or verona brown, many of the hairs, especially on shoulders, tipped with whitish, producing a hoary effect ; back thickly sprinkled with small white spots which become less distinct or obsolete on the shoulders; sides of nose and face grayish ; eye ring white ; sides of body some- times faintly washed with pale cartridge buff ; tail above, dark fawn color or mikado brown, the distal half mainly black or fuscous black, edged with pinkish buff or buffy white; tail beneath, pinkish buff, cinnamon buff, or pinkish cinnamon, more or less mixed with grayish white and fuscous black; feet whitish, washed with cartridge buff; under parts white. Measurements. — Average of 10 adults from San Francisco Mountain and vicinity of FlagstafP, Ariz.: Total length, 195.8 (185-210) ; tail vertebrae. 61.1 (55-68); hind foot, 30.5 (28-33). SknU: Average of 11 adults (3 males, 8 females) from San Francisco Mountain, Flagstaff, and Walnut Canyon: Greatest length, 35.5 (34.1-36.3) : palatilar length, 15.7 (15-16.5) : zygomatic breadth, 20.9 (20.2-21.7) ; cranial breadth, 17 (16.4-17.5) ; interorbital breadth, 7.3 (6.9-8) ; postorbital constriction. 12.5 (11.5-13.6) ; length of nasals, 12.1 (11.2-13.2) ; maxillary tooth row, 6.6 (6.2-7.8). Remarks. — The park spotted ground squirrel is the smallest form in the group. Although most resembling canescens., there is no evi- dence of intergradation with that race, the ranges of the two ap- parently being separated by the Mogollon Plateau. Intergradation with major is suggested, though not clearly shown by three specimens from Gallup and Thoreau, N. Mex., which agree closely with pratensis in external characters but have larger skulls. On the Painted Desert, this form passes into the subspecies C. s. crypto- spilotns. Specimens examined. — Total number, 62, as follows : Arizona: Aubrey Valley (Hualpai Indian Reservation), 1; Deadmans Flat (northeast of San Francisco Mountain), 9;'" Flagstaff (including 9 miles northwest and 12 miles northeast), 7; Grand Canyon (Bass Camp and Trash Tank), 8; Kendrick Peak (20 miles northwest of Flagstaff), 1; San Francisco Mountain, 20; Seligman, 1; Walnut Canyon (Coconino Natl. Forest). 15. 3" Mus. Vert. Zool. 154970—38- 230 NORTH AMERICAN FAUNA [No. 56 CITELLUS SPILOSOMA CRYPTOSPILOTUS (Mesitjiam) Desert Spotted Gkound Squirrel Spermophilus cryptospilotus Merriam, North Amer. Fauna 3 : 57, Sept. 11, 1890. Anlsonyx (Xerospermophilns) cryptospilotus Allen, Amer. Mus. Nat. Hist. Bull. 7: 240, 1895. \_Citellus] cryptospilotus Trouessart, Cat. Mamm., Sup., p. 341, 1904. Type. — Collected at "Tenebito" [=Dinnebito] Wash, Painted Desert, Ariz., August 17, 1889, by C. Hart Merriam; male juv., skin and skull no. ^^f, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 374). Range. — Northeastern Arizona, southeastern Utah, southwestern Colorado, and northwestern New Mexico ; north to Monticello, Utah ; east to Thoreau, N. Mex. ; south to Holbrook, Ariz.; west to the Little Colorado River (fig. 11). Zonal range: Upper and Lower Sonoran. External characters. — Similar in size to C. s. pratensis.f but colora- tion paler and more reddish (less brownish) ; similar to C. s. major but much smaller ; dorsal spots smaller and more numerous. Cranial characters. — Skull similar to that of fratensis; smaller than that of major. Color. — Upper parts fawn color or avellaneous, rather heavily sprinkled on hinder back with small whitish spots ; sides washed with pinkish buff or cartridge buff; feet cartridge buff; tail above, like the back and edged with pinkish buff with a fuscous patch near the tip ; tail beneath, pinkish buff or light pinkish cinnamon ; under parts white. Measurements. — Average of 6 adults from Painted Desert, Ariz. : Total length, 199.5 (190-210); tail vertebrae, 65 (58-72); hind foot, 31.8 (31-33). Skull: Average of 14 adults from Painted Desert (4) and Oraibi (10) : Greatest length, 36.2 (35.1-36.8) ; palatilar length, 15.9 (14.5-16.5) ; zygomatic breadth, 21.0 (20.9-22.4) ; cranial breadth, 17.5 (16.3-1S.4) ; interorbital breadth, 7.9 (7.2-8.6) ; postorbital constriction, 12.9 (11.9-13.8) ; length of nasals, 12.5 (11.7-13.5) ; maxillary tooth row, 7 (6.3-7.4). Remarks. — The desert s])otted ground squirrel is closely related to ' pratensis, its nearest neighbor on the west. The series from Wins- low, Ariz., indicates intergradation with major; specimens in the cinnamon phase agree in color with cryptospilotus while others in the drab phase closely resemble major; the skulls are somewhat larger than those of typical cryptospilotus. Specimens examined. — Total number, 42, as follows : Arizona: Chin Lee (15 miles southwest, Apache County), 1; Holbrook, 7; Oraibi (Navajo County), 13; Painted Desert, 6 (Diunebito Wash, 1; Moa Ave, 4; Tuba, 1) ; Winslow, 7. Colorado: McElmo Creek (south of Cortez, Montezuma County), 2.'^ New Mexico: Gallup, 3; Thoreau (McKinley County), 1. Utah: Lockerby (San Juan County), 1; Monticello (San Juan County), 1. CITELLUS SPILOSOMA OBSOLETUS (Kennicott) Kbnnicott's Spotted Ground Sqihebeil Sperriiophilns ohsoletus Kennicott, Acad. Nat. Sci. Phila. Proc. 1863: 157. ICitellusI obsoletus Trouessart, Cat. Mamm., Sup., p. 340, 1904. 81 Colorado Agr. College. 1938] REVISION OF THE GROUND SQUIRRELS 131 Type. — None designated; Lyon and Osgood (1909, p. 169), list seven specimens in the United States National Museum collection as being the material used by Kennicott; no. xrWs: U. S. Natl. Mus., is hereby designated as lectotype ; 9 , skin and skull ; collected 50 miles west of Fort Kearney, Nebr., August 9, 1857, by J. G. Cooper (orig. no. 44). Range. — Sandhill region of Nebraska; north to Todd County, S. Dak. ; east to Neligh, Nebr. ; south to Tuttle, Colo. ; west to Platte County, Wyo., and Greeley, Colo, (fig. 11). Zonal range: Upj)er Sonoran. Exter'nal characters. — Similar to C. s. major but averaging smaller ; dorsal spotting less distinct and tending to become obsolete, the white spots usually more distinctly edged with black; drab phase predominating. Cranial characters. — Skull similar to that of major but averaging smaller, with smaller audital bullae. Color. — Upper parts smoke gray, light drab, or avellaneous ; dorsal white spots of moderate size, but scattered and more or less indis- tinct, often nearly obsolete; most of the hairs on back tipped with black or fuscous black, these tips tending to form irregular and more or less indistinct spots, especially on hinder back; patch on front of face pinkish cinnamon or light vinaceous cinnamon; sides of nose and eye ring white ; sides of body washed with pale cartridge buff; front feet pinkish buff; hind feet whitish, washed with light pinkish cinnamon or cartridge buff; tail above, vinaceous fawn or wood brown, shaded on distal portion with fuscous and edged with cartridge buff; under parts white. Measurements. — Average of 10 adults (5 males, 5 females) from Nebraska: Total length, 214.3 (197-226) ; tail vertebrae, 64.B (56-79) ; hind foot, 31.8 (30-34). Skull: Avei-age of 10 adults (5 males, 5 females) from Nebraska: Greatest length, 38.9 (37.7-39.9) ; palatilar length, 17.4 (16.5-18) ; zygomatic breadth, 23 (22.2-23.6) ; cranial breadth, 17.6 (17-18.2) ; interorbital breadth, 7.8 (7-8.2) ; postorbital constriction, 13.2 (12.1-13.8) ; length of nasals, 13.3 (12.5-13.9) ; maxillary tooth row, 7.2 (6.9^7.5). Remarks. — Kennicott recognized the near relationship of this form to C. s. spiloso7na when he described it in 1863. Not until recently, however, when large series of specimens from many localities have been obtained, has it become clear that it is connected with the more southern races by a nearly complete series of intergrades. /Specimens examined. — Total number, 33, as f oIIoavs : Colorado: Avalo (10 miles east, Logan County), 1; Greeley, 1; Merino (Logan County), 1;'" Sterling, 3; Tuttle (Kit Carson County), 1; Wmy, 2. Kansas: St. Francis (9 miles northwest), 1.^ Nebraska: Cherry County, 2; Fort Kearney (50 miles west), 1; Kennedy (Cherry County), 6; Lincoln County, 2; Neligh, 1; O'Fallons Bluff (Lincoln Coimty), 1; Simeon (Cherry County). 1; Valentine, 4. South Dakota: White River (south fork), 1. Wyoming: Little Bear Creek (20 miles southeast of Chugwater), 1; Wheat- land, 1; Fort Laramie (Goshen County), 1; Spoon Butte (Goshen County), 1. •■"= Clevelanfl Mus. Nat. Hist. ^Kansas Univ. Mus. Nat. Hist. 132 NORTH AMERICAN FAUNA [No. 56 CITELLUS PEROTENSIS (Mebeiam) Peeote Ground Squirrel (Pis. 25, D; 30, D) SpermopMlus perotensis Merriam, Biol. Soc. Wash. Proc. 8 : 131, Dec. 28, 1893. [Citellus] perotensis Elliot, Field Columb. Mus. Pub., Zool. Ser. .4: 145, 1904. Type. — Collected at Perote, Vera Cruz, Mexico, June 8, 1893, by E. W. Nelson and E. A. Goldman; female adult, skin and skull, no. 54274, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 4976). Range. — Known only from the extreme eastern border of the Mexican tableland in the vicinity of Perote, Vera Cruz, at an alti- tude of 7,800 or 7,900 feet ; ranges to a point 10 miles south of Perote and eastward to within a few miles of Las Vigas (fig. 11). Zonal range: Upper Sonoran. External characters. — Similar to G. spilosoma pallescens but larger, with shorter tail; coloration more yellowish (less pinkish); dorsal spots buffy rather than white, smaller and less conspicuous (often nearly obsolete); under parts buffy instead of white; head marked with blackish. Cranial characters. — Skull similar to that of G. s. spilosoma but larger, with relatively narrower and higher brain case ; audital bullae broader and more flattened; molariform teeth heavier. Golor. — (Type, in worn pelage, June 8) : General tone of upper parts dull clay color, varied on hinder back with fuscous and very indistinctly speckled with pinkish buff ; top of head and face washed with fuscous black, sides of head washed with smoke gray; eyelids buffy white ; sides of body pinkish buff or cartridge buff ; under parts and feet similar or slightly paler; tail above, similar to the back, but distal two-thirds mixed with blackish and tipped with pale carti'idge buff ; tail beneath, pinkish buff, bordered at distal end with blackish. Variation. — Other specimens taken in June are considerably paler than the type, the general tone of upper parts varying from wood brown to drab, and some of the immature individuals are more con- spicuously spotted. Measurements. — Average of 11 adults from type locality: Total length, 250.4 (243-261) ; tail vertebrae, 70.5 (57-78), hind foot, 38.7 (38-40). STcull: Great- est length, 43.5 (42.2^4.5) ; palatilar length, 20.6 (20-21.5) ; zygomatic breadth, 26.4 (25.2-27.3) ; cranial breadth, 19.5 (19.1-20) ; interorbital breadth, 9.3 (8.8-9.8) ; postorbital constriction, 14 (13.3-14.7) ; length of nasals, 15.5 (14.5-16.5); maxillary tooth row, 8.7 (8.3-9). Remarks. — The Perote ground squirrel — the largest member of the spilosoma group — is clearly related to G. s. spilosonia but appar- ently does not intergrade with it. Its range apparently is restricted to the high plains at the extreme eastern border of the Mexican tableland. As pointed out by Merriam, this species bears a general external resemblance to G. richardsonii elegans^ but differs widely from it in skull characters and belongs in another subgenus. Specimens examined. — Total number, 16, from type locality. 1938] REVISION OF THE GROUND SQUIRRELS 133 POLIOCITELLUS, subgenus nov. [Characters and description on p. 42] CITELLUS FRANKLINII (Sabine) Fbanklin's Ground Squibbex (PI. 6) Arctomys franklinii Sabine, Linn. Soc. London Trans. 13: 587, 1822. Arctomys (Spermophilus) franklinii Richardson, Fauna Boreali-Amer. 1: 168, 1829. Spermophilus franklini Lesson, Manual Mamm., p. 244, 1827. [Citellus] franklini Trouessart, Cat. Mamm., Sup., p. 342, 1904. Tyjje. — Collected at Carlton House, Saskatchewan, probably by John Eichardson (Preble, 1908, p. 165) ; male, skin and skull, no. 61a, British Museum. Range. — Great Plains region of southern Canada and the upper Mississippi and Missouri Valleys; north to Athabaska Landing, Alberta; east to Lake Winnipeg, Manitoba, southeastern Wiscon- sin, and northwestern Indiana; south to southeastern Kansas, central Missouri, and central Illinois; w^est to Edmonton, Alberta, the Missouri Valley in North Dakota and South Dakota, central Nebraska and central Kansas ; introduced in Ocean County, N. J. (fig. 12). Zonal range: Transition and Upper Austral. External c h ar ac- ters. — About the size of G. parryii plesius but tail longer ; ears larger, suborbicu- lar. Cranial characters. — Skull long and narrow, with flattened super- ior outline, quite unlike any member of the subgenus Citellus; some- what resembling G. heecheyi but rostrum longer ; brain case narrower and less inflated; temporal region more constricted; and anterior border of zygomatic notch reaching only to posterior border of m ^. Golor. — Summer pelage (topotypes, July) : Head grayish, the bases of the hairs fuscous black, tips grayish white. (The color tone of the head varies with the amount of wear, worn pelages being de- cidedly darker than fresh pelages because of the exposure of the dark bases of the hairs.) Dorsum tawny olive or clay color, more or less shaded with fuscous; sides pinkish buff or cinnamon buff mixed with grayish white; thighs pale smoke gray, shaded with pinkish buff and fuscous ; front feet pinkish buff ; hind feet grayish i /^^fe^^^x ' ^^^\h \\ 1 ^ / \ '\ i .' ( i .i l 1 j y/////////Y/ ^"■^^7^^^ i. ! \///////uN ///K ^^i^^^^^^^ 1 \/////////J\ "i \/////////fjl W^/i?^\ 1 1 \//////////v i -v>^^^ ^^M- ^^^9 '■ -.' ^^^y^ —p--:. — ■: _ _^ S^^ "« Y' FiQDHB 12. — Distribution of Citellus franklinii. J34 NORTH AMERICAN FAUNA [No. 56 white, shaded with tilleul buff ; tail above and below, blackish mixed with tilleul buff, overlaid and bordered with creamy white; under parts pinkish buff or buffy white. Variation. — Certain specimens in worn summer pelage are de- cidedly darker above than those in the fresh pelage described, the general tone of the upper parts being sayal brown or ochraceous tawny; in these the exposure of the fuscous bases of the hairs pro- duces the effect of spotting. Winter pelage (North Dakota speci- mens in May) : Similar to fresh summer pelage but paler, the tips of the hairs on upper parts pinkish buff, the sides paler and more whitish; feet paler and less buffy. Specimens taken in April (Nebraska) and May (Alberta), being apparently in winter pelage, are darker than those described above, the general tone of the upper parts being clay color. Measurements.— AN&Yaige of 6 adult males from Saskatchewan (type locality) and Alberta: Total length, 388.7 (381-397); tail vertebrae, 144.7 (136-153); hind foot, 55.1 (53-57.5) ; ear from notch, 10.5 (10-11). Average of 5 adult females from Saskatchewan (Wingard and Indian Head) : Total length, 384.6 (363-401) ; tail vertebrae, 146.8 (133-156) ; hind foot, 52.8 (51-55) ; ear from notch, 10.5 (10-11). Skull: Average of 5 adult males from Saskatchewan and Alberta: Greatest length, 54.2 (53-54.6) ; palatilar length, 26.3 (25-27) ; zygo- matic breadth, 31.4 (31-32.1) ; cranial breadth, 21.1 (20.9-21.3) ; interorbital breadth, 12.3 (12.1-12.7) ; postorbital constriction, 13.1 (12.8-13.4) ; length of nasals, 18.4 (17.6^18.8) ; maxillary tooth row, 10.3 (10.2-10.4). Average of 5 adult females from Saskatchewan (Wingard and Indian Head) : Greatest length, 53.2 (52.1-55.1) ; palatilar length, 25.8 (25-27) ; zygomatic breadth, 30.6 (30.1- 31.4) ; cranial breadth, 20.5 (20.2-20.7) ; interorbital breadth, 12 (11.4-12.5) ; postorbital constriction, 13.1 (13-13.4) ; length of nasals, 18.4 (17.8-19.6) ; maxillary tooth row, 10.4 (10.2-10.7). Remarks. — Franklin's gi'ound squirrel is a very distinct species, having no close relatives and although it exhibits considerable varia- tion in color, these differences are individual and not correlated with geographical distribution. It was introduced into New Jersey at Tuckerton in May 1867, a single pair brought, from Illinois having escaped from their cage and established themselves in the sandy fields. Since then they have spread northward as far as Manahawken and westward to Speedwell (Stone, 1908, p, 80). Specimens examined. — Total number, 160, as follows : Alberta: Edmonton, 1; Sturgeon River (25 miles north of Edmonton), 2. Ilimois: West Northfield (Cook County), 1.'' Indiana: Benton County, 1; Lake Village (Newton County), 6; ^^ North Liberty (St. Joseph County), 3.'" Iowa: Ames, 2; Charles City, 1;=" Clay County, 9;'' Milford, 1;** Wall Lake, Kansas: Manhattan, 1; Onaga, 1. Manitoba: Carberry, 3; Manitoba House, 1; Winnipeg, 1. Minnesota : Browns Valley, 4 ; Cass Lake, 2 ; Elk River, 10 ; Fort Snelling, 1 ; ^' Heron Lake, 2; Ortonville, 10. Nebraska: Ames (Dodge County), 1; Columbus, 2; Kearney, 1; Niobrara, 1; Verdigris, 1. New Jersey: Tuckerton, 5. North Dakota: Blackmer (Richland County), 4; Devils Lake, 6; Pairmount 14; Fargo, 1; Fish Lake (Benson County), 4; Grafton, 1; Grand Forks, 1 Harwood (Cass County), 3; Kathryn (Barnes County), 1; La Moure, 1 3* Univ. Michigan Mus. Zool. ^ P. F. ETiekie collection. 2' Univ. of Notre Dame, s^ Dayton Stoner collection. 38 Field Mus. Nat. Hist. 1938] REVISION OF THE GROUND SQUIRRELS 135 Larimore, 2; Oakes, 3; Pembina, 5; Spring Lake (Rolette County), 1; Stump Lake, 2 ; Turtle Mountains, 2 ; ** Walhalla, 2. Ontario : Rainy River, 7/° Saskatchewan : Carlton, 4 ; Indian Head, 3 ; Oxbow, 1 ; Prince Albert, 1 ; ^ Win- gard, 5. South Dakota: Flandreau, 1; Fort Sisseton (Marshall County), 2; Scotland, 1 ; Vermillion, 1. Wisconsin: Delavan, 4. Subgenus OTOSPERMOPHILUS Brandt [Characters on p. 43] COLOE PATTEHN In the typical species and its near relatives the color of the upper parts is a mixture of various shades of buif, black, and white, the hinder back usually presenting a mottled appearance; some races have prominent whitish shoulder patches, others have solid black areas on the head or anterior back ; the bases of the hairs are fuscous ; the tail hairs are banded with black. PBXAGE AND MOLT worn. The pelage is full and soft when fresh, shorter and harsher when There is but one molt annually, which may occur at any time from early in May to early in September, depending in part on the climate. Breeding females are likely to molt later than males. Key to Species and Subspecies ^ Head black or brown. b.^ Shoulders and fore back solid black or brown huclcleyi b.^ Shoulders and fore back mixed with whitish, c* Upper parts brownish or huffy. d.} Size small (skull length less than 60 mm) atricapillus d.^ Size large(skull length more than 60 mm). f} Head black coucliii f.^ Head brown rupestris c.^ Upper I'.arts blackish varicyatufs - Head mixed with buffy. &.' Nape and shoulders with a dark median area. c.^ Fore back with a blackish patch douglusii c.^ Fore back without a blackish patch. d.^ White shoulder patches indistinct nesioticvs d." White shoulder patches distinct, e.' Upper parts darker. f} Feet wliitish sierrae f.^ Feet buffy. g} Under parts darker (more buffy) beecheyi ( (J.' Under parts paler (more whitish) nudipcs e.^ Upper parts paler. f} Size larger (skull length, 55-62 mm) fishcri f.^ Size smaller (skull length, 52-GO mm) parvulus b.^ Nape and shoulders without dark median area, c* Upper parts blackish. d.^ Head more blackish rariegattis d.' Head more buffy tularosac c? Upper parts brownish or buffy. d} Size smaller (skull length of 9 less than 57 mm) rnpinarnm d.' Size larger (skull length of 9 more than 57 mm). f.' Hinder back more tawny utah f.^ Hinder back more buffy grammnrus p. 141). p. 161). P- 130). 138). 136). 150). 160). p. 153). 14S). 158). 154). 156). 136). 145). p. 159). 146). 142). ** Univ. Michigan Mus. Zool. »« Field Mus. Nat. Hist. *• Royal Ontario Mus. 236 NORTH AMERICAN FAUNA [No. 56 CITELLUS VARIEGATUS (Eexleben) [Synonymy under subspecies] Speciiic characters. — Size large; hind foot, 53-65 mm; tail, 174- 263; skull length, 56-67.7. Skull somewhat resembling that of C. parryii but differing in the characters of the subgenus ; dorsal pro- file nearly flat ; brain case and interorbital region relatively broader ; parietal ridges meeting at posterior end of cranium to form a slight crest ; rostrum relatively broad, tapering gradually ; postorbital proc- esses stout, decurved; supraorbital borders of frontals slightly ele- vated ; zygomata less widely expanded ; audital bullae relatively long and narrow, the meatus tube very short; upper incisors stout, not prognathous; molariform teeth low-crowned (as described under subgeneric characters, p. 43). Color. — Head varying from pinkish buff or pinkish cinnamon to seal brown and fuscous black; upper parts varying from grayish white mixed with cinnamon buff to snuff brown, mikado brown, bone brown, and dark blackish brown; in some races the head and fore back, in others the whole dorsal surface is blackish ; the tail is mixed black or brown and buffy white. CITELLUS VARIEGATUS VARIEGATUS (Ebxleben) Mexican Rock Sqtjierei, (PI. 7) [Sciurusi variegatus Erxleben, Syst Regni, Anim 1 : 421, 1777. Sciurus huccatus Lichtenstein, Abhandl. k. Akad. Wiss. Berlin, 1827 (1830), p. 117. Spermophilus macrourus Bennett, Zool. Soc. London Proc. 1833; 41. ("West- Mexico" — in Zool. Society register.) Spermophilus variegatus Nelson, Science (n. s.) 8: 898, 1898. [Citellus] variegatus Elliot, Field Columb. Mus. Pub., Zool. Ser. 4 : 148, 1904. Otospermophilus variegatus Miller, U. S. Natl. Mus. Bull. 128: 181, 1924. Type. — None designated; type locality fixed at Valley of Mexico near the City of Mexico (Nelson, 1898, p. 898) . Range. — (I^entral Mexico, from southern Zacatecas and San Luis Potosi south to Michoacan and the Valley of Mexico ; west to Colima, Jalisco, and Nayarit (fig. 13). Zonal range: Upper and Lower Sonoran. External characters. — Size large; tail long (nearly half the total length) ; head blackish, more or less mixed with buff; general tone of upper parts gray, more or less heavily mixed with blackish ; tail mixed black and white. Cranial characters.— ^]sxi\\ of large size; zygomata heavy and rather widely expanded ; interorbital region broad ; postorbital proc- esses heavy ; nasals ending posteriorly on a line with ascending arms of premaxillae or slightly beyond. Color. — Winter pelage (Valley of Mexico) : Sides of nose pinkish buff or tilleul buff; front and sides of face brownish, mixed with buffy white; eyelids broadly margined with dull white; crown and occiput dark blackish brown ; hairs on the dorsal surface fuscous or fuscous black at base, banded with dull white or pinkish buff, some tipped with blackish; feet drab gray, tinged with fuscous; thighs washed with cinnamon buff or ochraceous tawny; tail blackish, mixed with buffy white and cinnamon buff; under parts grayish white or cinnamon buff. 1938] REVISION OF THE GROUND SQUIRRELS 137 Variation. — The majority of the specimens of this race have more or less black on the head* some however, have the hairs on the head fuscous basally , tipped with pinkish buff ; the amount of black show- ing on the dorsal surface varies considerably'^, some being only slightly darker than certain specimens of G. v. grammurus. Molt. — The molting season covers a considerable part of the year ; in a specimen from Nayarit, taken April 12, new pelage covers the head and anterior half of the back ; one from Guanajuato, June 20, and one from Michoacan, July 14, have nearly completed the molt; several from San Luis Potosi, August 17, are badly worn and new pelage is coming in on the an- terior upper parts ; one from Guanajua- to, November 7, had acquired a fresh pel- age on the head and the posterior half of the body, leaving a worn area of old pel- age on the shoulders and nape. Measurements.— Kvev- age of 8 adult males from central Mexico (Federal District, Pueb- la, and Michoacan) : To- tal length. 499 (470- f)20) ; tail vertebrae, 227.4 (197-249) ; hind foot, 62.7 (5^-65) ; ear from notch (dry), 18.9 (18-20). Average of 7 adult females from same region : Total length, 479 (447-510) ; tall vertebrae, 222 (212-233) ; hind foot, 60 (57-64) ; ear from notch, 19.2 (19-19.5, two specimens only) . Skull: Average of 9 adult males from central Mexico (Federal District, Puebla, Michoacan, Jalisco, San Luis Potosi, and Co- lima) : Greatest length, 65.0 (64.1-67.7) ; palatilar length, 31.5 (29.8-33) ; zygo- matic breadth, 40.5 (38.1-41.8) ; cranial breadth, 26.1 (25.5-26.6) ; interorbital breadth, 16.9 (15.5-18.1) ; postorbital constriction, 17.7 (16.7-18.8) ; length of nasals, 23.8 (22.4-24.5) ; maxillary tooth row, 13.4 (12.8-14). Average of 7 adult females from the same region: Greatest length, 62.1 (59-65.7) ; palatilar length, 29 (28.5-32.5) ; zygomatic breadth, 38.7 (36-42.4) ; cranial brcadtli, 25.5 (24.3-26.7) ; interorbital breadth, 15.7 (13.7-18.8) ; postorbital constriction, 17.9 (16.4-19.6) ; length of nasals, 21.8 (21-22.9) ; maxillary tooth row, 13.1 (12.7-13.7) . Remarks. —Poison (1898, p. 898) has shown the pertinence of Erx- leben's name Sciurus variegatus to the Mexican rock squirrel, and as suggested by him, this animal proves to be connected subspecifically with G. V. couchii and G. v. grammurus, as well as with G. v. rwpestris. FiGDRB 13. — Distribution of Citellus atricapillus and of the sub.ipecies of C. variegatus: 1, C. v. grammurua; 2, C. v. Utah; 3, O. v. tularosae; 4, O. v. huckleyi; 5, O. v. couchii; 6, C. V. rupeatris; 7, C. v. variegatus; 8, C. atricapillus. J38 NORTH AMERICAN FAUNA [No. 56 The subspecies is abundant over a large area in south-central Mexico. Specimens from Hacienda La Parada, Villar, and Rio Verde, in the State of San Luis Potosi, show approach to couchii in the darkening of the heads and paling of the backs; their skulls, however, agree well with those of variegatus and are distinctly larger than those of couchii. Specimens examined. — Total number, 95, as follows : Colima: Hacienda San Antonio (at base of Volcano of Colima) , 3. Guanajuato: Santa Rosa, 2; Silao, 1. Hidalgo: Encarnacion, 2; Ixmiquilpan, 2; Tulancingo, 1; Zimapan, 1. Jalisco: Ameca, 1; Atemajac, 9; Barranca Ibarra, 1; Chapala, 1; Etzatlan, 3; Guadalajara, 1 ; La Barca, 1 ; Lagos, 2 ; Ocotlan, 2 ; Plantinar, 1 ; Sierra Nevada de Colima, 1 ; Zacoalco, 1 ; Zapotlau, 6. Mexico : Mount Popocatapetl, 1 ; Amecameca, 1 ; Tlalpam, 6. Michoacan : Acambaro, 1 ; Los Reyes, 1 ; Mount Tancitaro, 2 ; Patzcuaro, 12 ; Querendaro, 1 ; Zamora, 2. Morelos: Tetela del Volcan, 1. Nayarit: Tepic, 1. Puebla: San Martin, 1. Queretaro: Tequisquiapan, 1. San Luis Potosi: Ahualulco, 1; Hacienda La Parada (20 miles northwest of San Luis Potosi), 12; Jesus Maria, 1; Rio Verde, 2; Villar, 5. Zacatecas: Berriozabal, 1. CITELLUS VARIEGATUS RUPESTRIS Allen Beown-headed Rock Squierel (Pis. 26, C; 31, C) Citellus (OtospermopliUus) grammurus rupestris Allen, Amer. Mus. Nat. Hist. Bull. 19: 595, Nov. 12, 1903. [Citellus varieciatus^ rupestris Elliot, Field Columb. Mus. Pub., Zool. Ser. 4: 150, 1904. OtospermopliUus grammurus rupestris Miller, U. S. Natl. Mus. Bull. 128: 181, 1924. Type. — Collected on Rio Sestin, northwestern Durango, Mexico, April 12, 1903, by J. H. Batty; female adult, skin and skull, no. 21231, Amer. Mus. Nat. Hist. (orig. no. 419). Range. — Eastern and western slopes of tlie Sierra Madre and ad- jacent plains on eastern side from southern Durango north to south- ern Chihuahua; east to Chihuahua City and Santa Rosalia; west to Sierra de Choix, Sinaloa (fig. 13). Zonal range: Upper and Lower Sonoran and Transition. External characters. — Similar to C. v. variegatus., but upper parts decidedly paler and brownish or buffy rather than blackish in tone ; head brown instead of black ; under parts more buffy ; similar also to G. V. couchii but paler and less blackish in general tone, and head brown instead of black. Cranial characters. — Skull similar to that of variegatus and couchii., but averaging longer and relatively narrower, with longer nasals. Color. — (Topotypes in April) : Top and sides of head, nape, and ears, bone brown; front and sides of face more or less washed with buffy white ; eye ring whitish or buffy ; hairs on dorsal area fuscous at base, shading to bone brown on the nape and to hair brown on the rump and sides ; subterminal band of dorsal hairs varying from buffy white to cinnamon buff ; tips of hairs brown or fuscous ; tail above and below, buffy white, mixed with fuscous and sometimes also with 1938] REVISION OF THE GROUND SQUIRRELS 139 light cinnamon buff ; feet tilleul buff or pinkish buff, the legs washed with cinnamon buff or ochraceous tawny ; under parts varying from cinnamon buff to buffy white. Variation. — The topotype series shows a large amount of variation in color in the upper parts, apparently due in part to fading and wear of the pelage. The general tone of the dorsal surface varies from bone brown to cartridge buff or cinnamon buff; in a specimen from near Guadalupe y Calvo, Chihuahua, and one from Sierra de Choix, Sin- aloa, the brown of the head and nape extends to or beyond the middle of the back. Molt. — Many of the specimens from Eio Sestin, taken in April, are badly worn; two (Apr. 12, 17) show new pelage coming in on the anterior half of the back. Measurements. — Average of 9 adult males from tyne locality (Allen, 19n3b, p. 596) : Total length, 503 (451-540) ; tail vertebrae, 233 (210-^248) ; hind foot (without claws), 56.7 (55.5-57) ; ear from notch (dry), 26.3 (25-28). Fourteen adult females: Total length, 499 (463-521) ; tail vertebrae, 227 (203-241) ; hind foot, 56 (54-60) ; ear, 26.3 (25-29). The hind foot, as measured dry from 7 of these specimens (5 males; 2 females) averages 61.1 (59-65). One aclult male from Durango City: 510; 238; 60; one adult female from Guazamota, Durango : 548; 263; 60. ^kull: Average of 7 adults (2 males, 5 females) from tvpe local- ity: Greatest length, 64 (61.2r-67) ; palatilar length, .30.6 (29-32.5) ; zygomatic breadth, 38.8 (37.5-40.9) ; cranial breadth, 25.3 (24.6-25.9) ; interorbital breadth, 15.2 (14.6-16) ; postorbital constriction, 17.2 (15..5-18.1) ; length of nasals, 23.3 (22.&-23.7) ; maxillary tooth row, 12.8 (11.9-13.3). Remarks. — This is a well-marked race, occupying an extensive area in western Mexico. Intergradation with C. v. grammurus is shown by series from Chihuahua and Santa Rosalia; most of the specimens from those localities have the head partly brownish black and agree generally in color with rupestris, though two adults from Chi- huahua and three young from Santa Rosalia are scarcely different from typical specimens of grammurus. The skulls are likewise inter- mediate in characters, resembling those of rupestris in shape, though smaller, and having larger molars than grammurus. A single specimen from Guazamota, southern Durango, which agrees in color with riipestns., has a skull agreeing in size and shape with skulls of variegatus. No intergrades of this race with couchii have been seen, but quite likely such may be found when collections are secured from the terri- tory intervening between their known ranges. Specimens examined — Total number, 58, as follows: Chihuahua: Chihuahua, 9; Samachique (Sierra Tarahumara), 4;" Santa Rosalia, 7; Sierra Madre, near Guadalupe y Calvo, 4. Durango: Coyotes, 3;*^ Durango, 1; Guazamota, 1; Rancho Bailon (east of Sestin Valley), 10;" Rio Sestin, 17. Sinaloa: Sierra de Choix (50 miles northeast of Choix), 1. Sonora: Oposura, 1. CITELLUS VARIEGATUS COUCHII (Baird) Couch's Rock Squirrel SpermopJiilus couchii Baird, Acad. Nat. Sci. Phila. Proc. 1855 : 332. S[permophilus] grammurus couchii Allen, Amer. Mus. Nat. Hist. Bull. 8: 68, 1896 ^^Amer. Mus. Nat. Hist. *i Field Mus. Nat. Hist. 140 NORTH AMERICAN FAUNA [No. 56 Citellus variegatus couchi Bailey, North Amer. Fauna 25 : 83, 1905. OtospermopMlus grammurus couchii Mearns, U. S. Natl. Mus. Bull. 56: 324, 1907. Type. — Collected at Santa Catarina (a few miles west of Mon- terey) , Nuevo Leon, Mexico, April 1853, by Lt. D. N. Couch; skin and skull, no. i3^ U. S. Natl. Mus. Range. — Northeastern Mexico, from southern Coahuila and Nuevo Leon north to the Chisos Mountains, Tex. (fig. 13). Zonal range: Upper and Lower Sonoran. External characters. — Similar to G. v. variegatus but smaller ; dor- sum paler and more brownish or buffy (less blackish); feet paler; top of head always black or dark brown. Similar to G. v. rupestris but head and upper parts darker and more blackish (less brownish or buffy) ; under parts darker. Granial characters. — Skull similar to that of variegatus but aver- aging smaller, especially in the males. Golor. — (Specimens in normal phase from Saltillo, Coahuila) : Front and sides of face grayish, with a tinge of brown ; crown, occi- put, sides of head, and ears, dark seal brown or black ; eyelids broadly margined above and below with grayish white; hairs on dorsal area fuscous at base, tipped with white on nape and shoulders, and with pinkish buff on middle and hinder back ; middle of back often show- ing a brownish patch. Variation. — Of eight specimens collected at the type locality, only one is of the normal color, the other seven being melanistic ; in these the head and upper parts are dark blackish brown, shading on hinder back to dark seal brown; feet and under parts seal brown; tail seal brown, shaded with blackish brown. In faded pelage these melanistic specimens show patches of cinnamon or walnut brown on the back. Molt. — Specimens taken at the type locality on April 13 show the molt in progress, the greater part of the body having acquired a new coat, while patches of the old faded pelage still remain on the rump and hinder back. Measurements. — ^Average of 15 adults (9 males, 6 females) from Santa Cata- rina and Saltillo, Mexico: Total length, 466 (430-493); tail vertebrae, 204 (174-235) ; hind foot, 60.9 (58-64). Skull: Average of 16 adults (8 males, 8 females) from the same localities: Greatest length, 60.1 (57-63.6); palatilar length, 28.6 (26-30.5) ; zygomatic breadth, 37.4 (34-39.3) ; cranial breadth, 24.7 (23.5r-25.5) ; interorbital breadth, 15 (12.3-17.4) ; postorbital constriction, 17 (15.9-18.1) ; length of nasals, 20.4 (18.5-21.9) ; maxillary tooth row, 12.4 (11.8-13). Remarks. — This race is closely related to variegatus and furnishes a link connecting the latter with G. v. grammurus. In the typical form, as found in Coahuila and Nuevo Leon, it is distinguished by the combination of a blackish or brownish head, sharply contrasted with a rather pale-colored back. Writing of these squirrels as seen at Santa Catarina, Nuevo Leon, Nelson (ms, notes) says: Although the bare sun-baked limestone slopes of the canyons where they live are practically devoid of any cover formed by vegetation and the rocks are pale gray, so that these animals live in a glare of intense light, yet at least 80 percent of those seen were melanistic. These black animals sunning themselves on the pale-colored rocks were very conspicuous. At Saltillo, Coahuila, where 12 specimens were taken, no black ones were seen, but in the canyons of the Sierra Guadalupe more than half of the animals seen were in the melanistic phase. 1938] REVISION OF THE GROUND SQUIRRELS 141 Four specimens from the Chisos Mountains, Tex., are best referred to this race, although two of them show apparent intergradation with grammurus in ha\dng the heads partly gray rather than solid black ; one of the black-headed ones has the black color reaching to the middle of the back, as in C. v. huckleyi. The skulls agree closely with those of typical G. v. couchii. One specimen from Boquillas, Tex., in the melanistic phase is wholly seal brown. Specimens examined. — Total number, 29, as follows : Coahuila: Carneros, 1; Saltillo, 12; Sierra Encarnacion, 1; Sierra Guadalupe. 1. Nuevo Leon: Santa Catarina, 8. Tamaulipas: Victoria, 1. Texas : Boquillas, 1 ; Chisos Mountains, 4. CITELLUS VARIEGATUS BUCKLEYI (Sr^vcK) Blvck-backed Rock Squikbei. (PI. 7) Spermophilus ImckJeyi Slack, Acad. Nat. Sci. Phila. Proc. 1861: 314. Spermophilus grammurus buckleyi Allen, Amer. Mus. Nat Hist. Bull. 8: 67, 1896. Citellus variegatus "buckleyi Bailey, North Amer. Fauna 25: 84, 1905. Otospermophilua grammurus buckleyi Mearns, U. S. Natl. Mus. Bull. 56: 323, 1907. Type. — Collected at Packsaddle Mountain, Llano County, Tex., about 1861 by S. R. Buckley ; entered as no. 998, Museum Acad. Nat. Sci., Philadelphia, but now reported missing. Range. — South-central Texas, "in the rough and semiarid mesquite country along the eastern slope of the southern arm of the Staked Plains' (Bailey, 1905, p. 84), from the upper Nueces River (Rock- springs) east nearly to San Antonio and Austin; north to San Saba River (fig. 13). Zonal range: Upper and Lower Sonoran. External characters. — Similar to C. v. couchii but upper parts more extensively blackish. Cranial characters. — Skull similar to that of couchii^ but averaging larger, with longer nasals; shorter and relatively broader than that of C. V. rupestris, with smaller molariform teeth. Color. — Head and anterior upper parts, to or beyond the middle of the back, black or dark seal brown, sometimes sparingly sprinkled with whitish hairs, especially along the sides ; hinder back and sides grizzled iron gray, the bases of the hairs fuscous, tipped with white or pale buff ; feet drab gray, more or less washed with fuscous ; tail fuscous black, variegated and tipped with pale buffy white ; under parts fuscous, more or less shaded with white and pinkish buff. Variation. — Wholly black individuals of this race have not been seen; one from Japonica, Tex., however, has the black extending along the back from nose to root of tail with a considerable mixture of whitish hairs along the sides; a juvenile specimen from Llano has the crown black, but the rest of the body grizzled gray. Molt. — Two specimens from Llano, taken May 12 and 13, sliow the molt in progress, fresh pelage covering the anterior part of the body to beyond the middle of the back. One from Japonica, taken July 7, shows fresh pelage covering nearly the whole body except a small strip across the middle of the back, where the old faded pelage still remains. 142 NORTH AMERICAN FAUNA [No. 56 Measurements. — Average of 11 adults (5 males, 6 females) from central Texas (Llano, Japonica, Rocksprlngs, Camp Verde) : Total length, 500 (470- 525) ; tail vertebrae, 226 (210-252) ; hind foot, 62 (60-65) ; ear from notch (dry), 19.7 (19-22). SJadl: Average of 15 adults (6 males, 9 females), from Mason and Llano, Tex.: Greatest length, 62.9 (60.6-64.8); palatilar length. 29.8 (28.5-31) ; zygomatic breadth, 38.3 (36.4-40.2) ; cranial breadth, 25.1 (24.7- 26.3) ; interorbital breadth, 14.5 (13.7-15.9) ; postorbital constriction, 17.7 (16.5-18.4) ; length of nasals, 23.6 (21.5-24.8) ; maxillary tooth rovp, 12.2 (11.5-13). Remarks. — This race occupies a small area at the eastern edge of the range of the species in Texas; it has developed large size and extensively blackish coloration. Apparently it intergrades with G. v. grammuriis in the region between the mouths of Pecos and Devils Rivers, the specimens from that section being referred to grammurus. Bailey (1905, p. 84), however, states: Apparently the open divide between the headwaters of the Nueces and the headwaters of the streams flowing into the Rio Grande separates the ranges of buckJeyl and coiichi [here referred to grammurus] with a neutral strip in which neither occurs. He adds (ms. notes) : I see no way to account for the peculiar coloration of this squirrel on the grounds of protective coloration. There are few if any dark colored rocks or burnt logs and trees [in its habitat]. The rocks are mainly light colored granite. Specimens examined. — Total number, 42, as follows: Texas: Austin (16 miles northwest), 1; Bull Creek (Travis County), 1; Camp Verde (7 miles west, Kerr County), 3; Fort Mason, 1; Ingram (Kerr County), 3;*" Japonica (Kerr County), 1; Llano, 11; Mason, 18; Rock- springs, 3. CITELLUS VARIEGATUS GRAMMURUS (Say) Say's Rock Squierel Siciurusi f/rammurus Say, Long's Exped. Rocky Mountains 2: 72, 1823. [Spermophilus grammurus^ var. grammurus Allen. Boston Soc. Nat. Hist. Proc. 16: 293, 1874. Anisonyx {Otospermophilus) grammurus Allen, Amer. Mus. Nat. Hist. Bull. 7: 237, 1895. [Citellus variegattis] grammurus Elliot, Field Columb. Mus. Pub., Zool. Ser. 4: 149, 1904. Otospermophilus grammurus Mearns, U. S. Natl. Mus. Bull. 56: 315, 1907. Citellus grammurus grammurus Miller, U. S. Natl. Mus. Bull. 79: 208, 1912. Citellus variegatus juglans Bailey, Biol. Soc. Wash. Proc. 26: 131, 1913 (Glen- wood, N. Mex.). Otospermophilus grammurus grammurus Miller, U. S. Natl. Mus. Bull. 128: 180, 1924. Type. — None designated ; specimen on which Say's description was based was taken on Purgatory River, near mouth of Chacuaco Creek, Las Animas County, Colo. (Cary 1911, p. 87). Range. — Mountain valleys and foothills in Colorado, New Mexico, Arizona, southeastern and southwestern Utah, southern Nevada, northwestern Chihuahua, and eastern Sonora ; north to eastern Lari- mer County, Colo,; east to Baca County, Colo.; south to southern Texas (Eagle Pass), and southern Sonora; west to the Providence Mountains, Calif., and Charleston Mountains, Nev. (fig. 13). Zonal *2 Cleveland Mus. Nat. Hist. 1938] REVISION OF THE GROUND SQUIRRELS 143 'lange: Upper Sonoran and Transition (4,200-8,500 feet in New Mexico). External characters. — Similar to C. v. couchii but much paler, and head without any black. Cranial characters. — Skull very similar to that of couchii but averaging slightly shorter, though of the same breadth ; nasals longer, projecting slightly beyond the posterior ends of the premaxillae; niolariform teeth smaller. Color. — (April specimen in unworn pelage, 18 miles south of La Junta, Colo.) : Head and occiput pinkish buff, faintly shaded with fuscous; sides of nose cartridge buff; ej^e ring white; fore part of back, shoulders, and sides grayish white, slightly mixed with brown- ish ; hinder part of back and rump cinnamon buff, moderately varied with clove brown; bases of hairs on dorsal area clove brown; ears hair brown, shaded with pinkish buff; front legs buffy white; hind legs cinnamon buff; fore and hind feet cartridge buff; tail mixed pinkish buff and bone brown, edged with grayish white; under parts buffy white, shaded with pinkish buff. Variation. — September specimens from Bear Canyon, N, Mex., (about 12 miles northeast of Raton) and others from various parts of the range of the subspecies are considerably darker than the April specimens described above ; the middle and hinder back pinkish cinna- mon, heavily washed with brown (the general tone about cinnamon brown) ; head pinkish cinnamon more or less shaded with brown ; sides of nose pinkish buff; ears clove brown outside, wood brown in- side; feet pinkisli buff or cinnamon buff; tail mixed black and buffy white; edged with grayish white. Occasional specimens (Fort Hua- chuca and Graham Mountains, Ariz.) have the back clear grayish, with only a very slight wash of buff. Molt. — There is normally but one molt annually, in July or August. Two specimens (male and female) taken at San Pedro, N. Mex., July 5 and 6, show new pelage covering the anterior half of the body, the posterior half being badly worn. An adult female from Big Sandy Creek. Ariz., July 21, shows a similar progress of the molt. An adult male from Sierra Grande, N. Mex., August 19, is molting irregularly on the dorsal surface. An adult female from Red Lake, Ariz., Sep- tember 7, is badly worn on the anterior half of the body and has the posterior portion covered with a fresh, full pelage. As the season advances the pelage usually becomes paler and more grayish, due apparently to wearing off of the buffy tips to the hairs of the dorsal area. Measurements. — Average of 11 adults (3 males, 8 females) from southeastern Colorado (La Junta, Trinidad, Canon City) : Total length, 467.7 (434-510) ; tail vertebrae, 210.3 (19S-235) ; hind foot, 57 (53-GO) ; ear from notch (dry), 17 (15-19) ; average of 10 adults (4 males, 6 females) from southeastern Arizona (Fort Huachuca, Oracle, Santa Catalina Mountains): 477; 204; 58; 19.5. Skull: Average of 6 adult males from northeastern New Mexico (Polsom, Chico Springs, Sierra Grande) and Trinidad, Colo.: Greatest length, G0.9 (58.8-63.5) ; palatilar length, 29.3 (28.5-30); zvgomntic breadth, 37.9 (30.4-39.1); cranial breadth, 25 (24.1-25.7) ; interorbital breadth, 14.S (13.5-15.8) ; postorbital con- striction, 17.6 (16.8-18.6) ; length of nasals, 21.9 (20.6-23) ; maxillary tooth row, 11.7 (11.3-12). Average of 10 adult females from southeastern Colorado (Trini- dad, La .lunta. Canon City) and northeastern New Mexico (Clayton, Bear Can- yon) : Greatest length, 59.7 (57.8-62.7) ; palatilar length, 28.5 (26.8-29.7) ; zygo- matic breadth, 36.6 (34-38.9) ; cranial breadth, 24.9 (24.1-25.6) ; interorbital breadth, 14.7 (13.5-15.6); postorbital constriction, 17.4 (16.2-18.2); length of l^ NORTH AMERICAN FAUNA [No. 56 nasals, 21.1 (20-22.3); maxillary tooth row, 11.8 (11.3-12.3). Average of 12 adult females from Fort Huachuca, Ariz.: 60.5; 29.2; 37.1; 25.3; 14.8; 18; 21.8; 11.8. Remarks. — Say's rock squirrel has a very wide range and is sub- ject to great individual and seasonal variation. No appreciable departure from the typical coloration is found in the large series examined from New Mexico and Arizona, including the form ^^jug- lans" named by Bailey from Glenwood, N. Mex. A series of 10 specimens from the Davis Mountains, Tex., shows approach to couchii in the darkening of the heads of about half of the series; only one individual, however, has a wholly black head. The skulls average somewhat larger than those of either grammurus or couchii^ being in fact, about the size of those of O. v. tuehleyi. A series of 15 specimens from the Rio Grande, between the Pecos River and Devils River, shows intergradation with liucMeyi in par- tial darkening of the heads and shoulders of 5 individuals, the ma- jority being almost typical of grammurus. Skulls of two of the specimens are larger even than those of huokleyi^ while those of three other adults are typical of grammurus. Specimens from Colonia Garcia, Chihuahua, and from numerous localities in Sonora as far south as Camoa, on the Rio Mayo, are only slightly darker than typical grammurus. One from Oposura and one from Ortiz, however, have considerable black on the nape and shoulders, thus showing approach to G. v. rupestris; the skulls of all of these from Chihuahua and Sonora agree closely with typ- ical grammurus and do not approach rupestris in any characters. This race intergrades with the subspecies utah in southwestern and probably in eastern Utah; the few specimens examined from western Colorado appear to be typical grammurus. There is no indication that this species intergrades with heecheyi, specimens from the Providence Mountains, Calif., being typical grammurus. Specimens examined. — Total number, 437, as follows : Arizona: Anderson Mesa (Coconino County), 1; Apache (Cochise County), 2; Apache Maid Mountain (Coconino County), 2; Baker Butte (Coconino County), 2; Bates Well (20 miles south of Ajo, Pima County), 1; Beale Spring (near Kingman, Mohave County), 1; Big Sandy Creek (near Owens, Mohave County), 2; Bill WUliams Mountain, 1; Bisbee, 1; Black River (5 miles above mouth of White River), 1; Blue River (Cosper Ranch, Greenlee County), 3; Calabasas (Santa Cruz County), 4; Chiricahua Ranch (San Carlos Indian Reservation, Graham County), 1; Chiricahua Mountains, 2; Crown King (Yavapai County), 1; Congress Junction (Yavapai County), 1; Camp Verde (Yavapai County), 2; Dos Cabezos (Cochise County), 1; Fish Creek (Tonto National Forest, Maricopa County), 1; Fort Bowie (Cochise County), 2; Fort Grant (Graham County), 3; Fort Huachuca, 30; Fort Lowell, 1; Fort Whipple (Yavapai County), 1; Galiuro Mountains (Graham County), 1; Graham Mountains, 12; Grand Canyon (Coconino Plateau), 8; Huachuca Mountains, 12; Hualpai Mountains, 9; Keams Canyon (Navajo County), 1; Kingman, 1;'^ Kirkland (Yavapai County), 1; La Osa (Pima County), 1; Mayer (Ya- vapai County), 2; Mineral Park (Mohave County), 2; Montezuma Well (near Camp Verde, Yavapai County), 4; Mowry (Patagonia Mountains), 1; Nantan Plateau (San Carlos Indian Reservation), 3; Nogales, 2; Oatman, 1;" Oracle (Pinal County), 15; Oak Creek (15 miles southwest of Flagstaff), 2; Patagonia Mountains, 5; Payson (Gila County), 1; Phantom Ranch (Grand Canj^on), 2; Pine Spring (8 miles north, Hualpai *' Univ. Michigan Mus. Zool. « Cleveland Mus. Nat. Hist. 19381 REVISION OF THE GROUND SQUIRRELS 145 Indian Reservation), 1; Portal (Cochise County), 2; Prescott, 3; Prieto Plateau (east fork Eagle Creek, Greenlee County), 1; Red Lake (Coconino County), 2; Rice (Gila County), 1; Roosevelt (Gila County), 2; San Bernardino Ranch (Mexican boundary), 2; San Francisco Mountain, 3; Santa Cataliua Mountains, 2; Santa Cruz River (near Monument 118), 2 ; Santa Rita Mountains, 3 ; Sierra Ancha Mountains, 2 ; Simmons (Yavapai County), 1; Springerville, 2; Trumbull Mountains (Mohave County), 5; Tubac, 1; Tucson Mountains, 1; Vicksburg (Yuma County), 1; Warsaw Mills (Pajaritos Mountains, near Monument 132), 4; White- river (10 miles north, Navajo County), 1. California: Providence Mountains, 10. Chihuahua: Colonia Garcia, 5; San Luis Mountains, 4. Colorado: Ashbaugh's Ranch, Montezuma County, 1; Boulder, 2; Buena Vista, 1 ; Canon City, 6 ; Chaffee County, 2 ; " Grand Junction, 1 ; La Junta (18 miles south), 3; La Veta, 1;*^ Lyons, 1; Piuewood (Larimer County), 1; Plateau Creek (12 miles east of Tunnel, Mesa County), 1; Rifle, 1; Trinidad, 7. Nevada: Cedar Basin (Clark County), 4;** Charleston Mountains, 11;** Sheep Mountains (Clark County), 1/^ New Mexico: Animas Mountains, 2; Apache (Grant County), 3; Arroyo Seco (Taos County), 1; Bear Canyon (5 miles northeast of Bell, Colfax County), 3; Burro Mountains (Grant County), 3; Capitan Mountains, 16; Carlsbad, 2; Carlsbad Cave, 1; Carrizozo (14 miles north), 1;" Chico (CoLfax County), 1; Cienequilla (10 miles southwest of Taos), 4; Clayton, 3; Cloverdale, 1; Copperton (south of Mt. Sedgwick, Valencia County), 1; Florida Mountains (Luna County), 2; Folsom, 1; Fort Wingate (McKinley County), 1; Gallup, 1; Garfield (Dona Ana County), 1; Gila (Grant County), 1; Gila National Forest (east fork Gila River), 1; Glen- wood (Catron County), 1; Grant (Valencia County), 3; Guadalupe Mountains, 1; Hachita, 3; HighroUs (Otero County), 4;" Hondo Canyon (Taos County), 1; Hondo River (White Mountains, Lincoln County), 1; Jicarilla Mountains, 3; Lincoln, 2; Lima (Catron County), 1; Magdalena Moimtains, 2; Manzano Mountains, 3; Mescalero, 2;" Mimbres Mountains (head of Rio Mimbres), 1; Mosquero (Harding County), 2;" Pecos (San Miguel County), 1; Red River (8,200 feet altitude, Taos County), 1; Red- rock (Grant County), 1; Riley (Socorro County), 2; Rinconada (Rio Arriba County), 2; Rio Puerco (Valencia County), 1; Ruidoso (Lincoln County), 1; San Luis Mountains, 0; San Pedro (Santa Fe County), 3; Santa Rosa, 4; San Mateo Mountains (Socorro County), 2; San Mateo Mountains (Valencia County), 1; Sierra Grande, 1; Sweetwater (15 miles southwest of Springer), 2; Tres Piedras (Taos County), 1; Tularosa, 3; Zuni Mountains (Valencia County), 2. Sonera: Bacerac (15 miles east), 1; Camoa, 1; Cerro Blanco, 3;^' Guadalupe Canyon (Monument 73, Mexican boundary line), 2; Hermosillo, 3; Mag- dalena, 1; Nogales (and 32 miles south), 8; Ortiz, 1; Pilares, 1; Provi- dentia Mines, 4;" San Jose Mountain (8 miles south of Monument 93, Mexican boundary line), 3; Santa Cruz, 1. Texas: Castle Mountains (Cx-ockett County), 1; Comstock (and 40 miles north- west), 2; Davis Mountains, 11; Devils River, 6; El Paso, 1; Fort Davis, 2; Guadalupe Mountains, 2; Langtry, 1; Painted Cave (near mouth of Pecos River), 4; Pecos High Bridge, 1. Utah: Beaverdam Mountains, 1; Pine Valley (Washington County), 2; Santa Clara, 2. CITELLUS VARIEGATUS TULAROSAE Benson Malpais Rock Squibbel Citellus grammurus tularosae Benson, Calif. Univ. Pubs., Zool. Ser. 38: 336, Apr. 14, 1932. Otospennophilus grammurus tularofiae Bradt, Jour. Mammal. 13 : 324, 1932. Type. — Collected at French's Ranch, 5,400 feet altitude, 12 miles northwest of Carrizozo, Lincoln County, N. Mex., October 28, 1931, " Univ. Michigan Mus. Zool. ** Cleveland ifus. Nat. Hist. ^''D. R. Dickey collection (California Inst. Technology). «• New Mexico State College. *'' F'ield C^olumbian Mus. 154970—38 10 146 ' NORTH AMERICAN FAUNA [No. 56 by Seth B. Benson; male adult, skin and skull, no. 50935, Mus. Vert. Zool. (orig.no. 1603). Range. — "Lava beds of the Tularosa Basin in Lincoln and Otero Counties, New Mexico" (Benson) (fig. 13). Zonal range: Lower Sonoran. External characters. — ^Very similar in color to typical G. v. vaHe- gatus., but bead never black and hinder back more tawny ; similar in size to G. V. grammurus but coloration distinctly darker (more black- ish), due largely to the darker bases of the hairs on both dorsal and ventral surfaces; hinder back darker tawny; hind feet slightly darker. Granidl characters. — Skull similar to that of grammurus (only one adult skull examined; extent of variation not known). Golor. — ^Winter pelage (October) : Head grizzled with fuscous or black and light buff ; eye ring white ; ears blackish externally, edged with buff, cinnamon buff on inner surface ; hairs on fore back fuscous black basally, tipped with white; hairs on hinder back dark fuscous basally, tipped with sayal brown and light buff; front feet pinkish buff, hind feet light pinkish cinnamon, all more or less grizzled with blackish; tail mixed black and grayish white; under parts grayish white or pinkish buff, the bases of the hairs dark fuscous. Measurements. — Adult male (type) : Total length, 488; tail vertebrae, 206; hind foot, 60; ear from notch (dry), 18. SuMdult female: 437; 172; 53; 17. Skull: Adult male (type) and subadult female: Greatest length, 63, 57.5; pala- tilar length, 30, 27; zygomatic breadth, 38.6, 34.7; cranial breadth, 25.8, 25.1; interorbital breadth, 15.5, 14.7; postorbital constriction, 18.3, 17.8; length of nasals, 23, 20.9; maxillary tooth row, 12.1, 11.8. Remarks. — The Malpais rock squirrel, although occupying a very limited area in south-central New Mexico, and entirely surrounded by another wide-ranging race — grammurus — is apparently a well- marked form. It appears to be confined exclusively to the beds of dark-colored lava rock where this and other dark forms of rodents have developed. Specimens examined. — Total number, 4, as follows : New Mexico : French's Ranch, 12 miles northwest of Carrizozo, 3 ; ^ Malpais Lava Beds (near Carrizozo), 1.** CITELLUS VARIEGATUS UTAH Merbiam Utah Rock Squirrel Citellus grammurus utah Merriam, Biol. Soe. Wash. Proc. 16 : 77, May 29, 1903. Citellus variegatus Utah Elliot, Field Columb. Mus. Pub. Zool. Ser. 6: 115, 1905. OtospermopJiilus grammurus utah Miller, U. S. Natl. Mus. Bull. 128: 181, 1924. Type. — Collected at foot of Wasatch Mountains, near Ogden, Utah, October 10, 1888, by Vernon Bailey; female adult, skin and skull, no. 186468, U. S. Natl. Mus. (Merriam collection, no. ) (orig. no. 291). Range. — Central Utah, from the Wasatch Range south to the Beaver Mountains; also the Kaibab Plateau, Ariz, (limits of range imperfectly known) (fig. 13). Zonal range: Transition and Upper Sonoran. «Mus. Vert. ZooL 1938] REVISION OF THE GROUND SQUIRRELS 147 External characters. — Similar to C. v. grammurus^ but head and posterior back darker (more tawny), especially in unworn winter pelage. Cranial characters. — Skull similar to that of grammuruSs but aver- aging smaller. Color. — Winter pelage (October) : Head mixed pinkish buff and fuscous ; a broad buffy white eye ring ; shoulders and fore back gray- ish white, the bases of the hairs fuscous; hinder back snuff brown or mikado brown, sj)aringl3^ tipped with light buff ; lower sides grayish white; feet pinkish buff or grayish buff; tail mixed pale buff and fuscous black ; under parts buffy white or pale pinkish buff'. Molt. — An adult female (nursing) taken at Nephi, Utah, July 5, is in worn winter pelage and shows new pelage coming in on the head and nape. Measurements. — Average of 7 adult males from Utah (Ogden, Salt Lake City, Provo) : Total length, 467 (454-495) ; tail vertebrae, IDS (185-210) ; hind foot, G0.5 (59-63) ; ear from notch (dry), 19.5 (18.5-21). Average of 5 adult fe- males from Utah (Ogden, Provo, Salt Lake City, Marysvale) : Total length, 438 (425-460); tail vertebrae, 189 (180-199): hind foot, 58.8 (56-61); ear from notch (dry), 18.7 (18-19). Skull: Average of 4 adult males from Utah (Ogden, Provo, Salt Lake City) : Greate.st length, 60.3 (57.5-63) ; palatilar length, 29.2 (28-30.5) ; zygomatic breadth, 36.9 (35.5-38) ; cranial breadth, 25.3 (24.8-2-5.8) ; interorbital breadth, 14.7 (14.2-15.2) ; postorbital constriction, 17.5 (17.1-18.3) ; length of nasals, 21.1 (19.8-22.4); maxillary tooth row, 11.5 (11.4-12). Aver- age of 6 adult females from same localities: Gi'eatest length, 57.9 (5(>-59.5) ; palatilar length, 27.7 (27-28.5) ; zygomatic breadth, 35.6 (34.6-36.8) ; cranial breadth, 24.1 (23.5-24.6) ; interorbital breadth, 13.5 (13.2-14.3) ; postorbital constriction, 16.9 (16-17.5) ; length of nasals, 20.6 (18.9-21.9) ; maxillary tooth row, 11.3 (10.7-11.6). Remarks. — The Utah rock squirrel appears to be a recognizable race, but it is difficult to define the limits of its range. Upon com- parison of typical specimens in unworn v.inter pelage with a similar series of graramurus from southeastern Colorado — the type region — marked differences in color are noticeable. However, throughout the wide range of grammurus in New Mexico and Arizona many indi- vidual specimens are found that agree very closely in color with specimens of utah. But nowhere in northern Utah do we find speci- mens to match the pale grayish or cinnamon buff type occurring in Colorado, New Mexico, and southeastern Arizona. Two specimens from the Kaibab Plateau, Ariz., appear to be refer- able to Utah., but whether this race has a continuous range from the Beaver Mountains south to the Kaibab is not known; grammurus occurs in practically typical form in extreme southwestern Utah and southern Nevada. Specimens examined. — Total number, 34, as follows: Arizona: Big Spring (Kaibab Plateau), 1; Kaibab Forest, l.'^ Utah: Beaver, 1; Cedar Fort (Utah County), 1; Florence Canyon, 35 miles north of Green River (city), 6;°*" Logan, 3:"^^ Marysvale, 2; Murray 1; Nephi, 1; Ogden, 8; Parowan, 1;^^ Provo, 5; Provo Canyon, 1;" Salt Lake City, 2. «»Mus. Vert. Zool. ^ Carnegie Mus. WTItah State. Agr. College. "^ Cleveland Mus. Nat. Hist. 148 NORTH AMERICAN FAUNA [No. 56 CITBLLUS BEBCHETI (Richardson) [Synonymy under subspecies] Speci-jh characters. — Size small to medium ; hind foot, 50-63.5 mm ; tail, 137-198; skull length, 51.6-62.4. Skull essentially similar to' that of O. variegatus grammurus except in size. Color. — Head varying from avellaneous or pinkish cinnamon to wood brown or sayal brown; upper parts snuff brown, wood brown, or sayal brown, flecked with buffy white or cinnamon buff; sides of neck and shoulders white or whitish, this color extending backward as two divergent stripes to about the middle of the back, leaving a dark triangular area between ; under parts buff, of varying intensity. CITELLUS BEECHETI BEECHEYI (Richakdson) CAUFOENIA GROtrND SQtriEBEIi (PI. 8) Arctomys (Spermophilus) heecheyi Richardson, Fauna Boreali- American a 1: 170, 1829. Spermophilus deecheyi F. Cuvier, Sup. a I'hist. natur. Buffon 1 : 331, 1831. ISpermophilus prammurus] var. beecheyi Allen, Boston Soc. Nat. Hist. Proc. 16: 293, 1874. Citellus variegatus beecheyi Elliot, Field Columb. Mus. Pub., Zool. Ser. 6: 114, 1905. Oto spermophilus beecheyi Mearns, U. S. Natl. Mus. Bull. 56 : 324, 1907. Citellus grammurus beecheyi Miller, U. S. Natl. Mus. Bull. 79 : 298, 1912. Citellus beecheyi beecheyi Grinnell, Calif. Acad. Sci. Proc. (4) 3: 346, 1913. Otospermophilus grammurus beecheyi Miller, U. S. Natl. Mus. Bull. 128: 180, 1924. Type. — No. 222a, British Museum, skin with skull inside ; locality not stated; habitat given as "neighborhood of San Francisco and Monterey, in California." Range. — ^Western California, from San Francisco Bay south to northern San Diego County; eastward through the coast ranges and the San Gabriel Mountains (fig. 14). Zonal range: Upper Sonoran and Transition. External characters. — Similar to C. variegatus grammurus but darker; white area of the shoulders divided by a dark triangular patch reaching to the crown ; ears darker on outer surface. Sunilar to C. h. dougla^ii, but slightly darker; white shoulder patches less extensive,, and foreback without a black patch between the white stripes. In comparison with the other races of heecheyi, this form is darker (more brownish) on the head and back, and more buffy on the under parts. Cranial characters. — Skull similar to that of C. v. grammurus but smaller and relatively narrower in the postorbital region; nasals narrower posteriorly. Color. — Fresh fall pelage (San Mateo County, Calif., December) : Top of head pinkish cinnamon, shaded with fuscous ; eye ring buffy white; ears fuscous black externally and on the upper margin, pale cinnamon buff on inner surface and posterior outer margin ; hairs of upper parts fuscous black at base, tipped with pinkish cinnamon, the general tone near snuff brown; sides of neck _ and shoulders dull white, this color extending backward as two divergent stripes that fade out about the middle of the back; sides of body more or less 1938] REVISION OF THE GROUND SQUIRRELS 149 extensively flecked with dull white ; feet pale pinkish buff ; under parts pinkish buff ; tail mixed black and pinkish buff. Variation. — The pelage in simimer is slightly paler, due to wear and fading. Molt. — The annual molt occurs usually in July, but may be deferred imtil Sep- tember. An adult male from Marys- ville Buttes, taken July 15, is in much worn pelage and shows new pelage starting in a small area on the fore back. An adult female taken on the same day at the same place is in old worn pelage and shows no indica- tion of molting. A subadult male from Salinas, September 4, shows new pelage on the head and the posterior half of the body. Measuremen ts. — Aver- age of 10 adult males from type region (Berk- eley, Walnut Creek, Stanford University, Boulder Creek, Monte- rey, Mansfield) : Total length, 434 (410-460) ; tail vertebrae, 177 (156- 190) ; hind foot, HO (57- 61 ) ; ear from notch (dry), 19.9 (18-21). Average of 10 adult fe- males from same sec- tion: Total length, 401 (370-442) ; tail verte- brae, 158 (137-180) ; hind foot, 56 (53-59) ; ear from notch (dry), 20.7 (19-22). Skull: Average of 20 adult males from Contra Costa County: Greatest length, 59.4 (57-62.4) ; palatilar length, 28.8 (27-30.5) ; zygomatic breadth, 38.3 (36.3-40.5) ; cranial breadth, 24.5 (23.4-25.9) ; interorbital breadth, 14.7 (13.2-15.8) ; postorbi- tal constriction, 15.7 (14.8-16.9) ; length of nasals, 22.1 (20-24) ; maxillary tooth row. 12 (11.2-12.9). Average of 20 adult females from same locality: Greatest Figure 14. — Distribution of the subspecies of Citellus beecheyi: 1, C. b. doiiglasii; 2, C. b. sierrae; 3. O. h. ftsheri; 4,0. b. beecheyi; 5, C. b. parvulus; 6, C. b. nesioticus ; 7,(7. b. nudipes; 8, C. b. rupinarum. 150 NORTH AMERICAN FAUNA [No. 56 length, 57.1 (53.9-60.4) ; palatilar length, 27.5 (26^30) ; zygomatic breadth, 36 (33.6-38.6) ; cranial breadth, 23.6 (22.7-25.2) ; interorbital breadth, 13.8 (12.9- 15.4) ; postorbital constriction, 15.6 (13.7-16.7) ; length of nasals, 21 (19.7-22.4) ; maxillary tooth row, 11.9 (10.6-12.7). RemarJcs. — Any attempt to divide C. heecheyi into subspecies is certain to be unsatisfactory ; this is because of the large amount of individual variation that is found in all races and also because of the diversified nature of the country in which the animals live. The present race is the darkest of all the forms and is typical only in the coastal region from San Francisco Bay southward to Ventura County ; from there southward the animals become paler and smaller, grading into C. h. -fisheri in the Tehachapi Mountains, into G. h, parvulus in the San Bernardino Mountains, and into C. h. nudipes in the coastal region of San Diego County. In many localities, the variation in the series is so great that while some of the specimens are typical of beecheyi, one or more may closely resemble one of the other subspecies. Specimens examined. — Total number, 197, as follows: California: Alhambra, 1; Aptos (5 miles south, Santa Cruz County), 2; Arroyo Seco (10 miles south of Paraiso Springs, Monterey County), 2; Arroyo Seco Canyon (near Pasadena. Los Angeles County), 3;" Bear Basin (head of Carmel River, Monterey County), 1; Berkeley, 2; Bitterwater (San Benito County), 3; Boulder Creek (Santa Cruz County), 3; Corral Hollow (8 miles southwest of Tracy), 1;^ Contra Costa County, 50 (skulls) \^^ Cor- ralitos (Santa Cruz County), 11; ^ Del Norte (7 miles southeast, Monterey County), 6; Fremont Peak (Gabilan Range, Monterey County), 1; Gaviota Pass (Santa Barbara County), 2; Half Moon Bay, 1; Hay ward, 1; Idria Mines (San Benito County), 4; Jamesburg (Monterey County), 1; Jolon (Monterey County), 1; Laguna Ranch (Gabilan Range, San Benito County), 1; Las Virgines Creek (Los Angeles County), 1: Los Gatos, 1; Lytle Creek (San Bernardino County), 1; Mansfield (Monterey County), 4; Monterey, 6; Pacific Grove (Monterey County), 1; Paraiso Springs (Monterey County). 4; Paso Robles, 1; Pescadero, 1; Pine Valley (head of Carmel River, Mon- terey County), 2; Posts (Monterey County), 1; Pozo (San Luis Obispo County), 3; Priest Valley (Monterey County), 1; Redwood City, 1; Salinas, 1; San Francisco, 6; San Gabriel, 1; San Gabriel Mountains (Heninger Flats), 8; San Luis Obispo, 1; San Pedro (Point Firmin). 10; San Rafael Mountains (Santa Barbara County), 1; San Simeon (San Luis Obispo County), 2; Santa Barbara, 3; Santa Clara, 1; Santa Cruz, 2; San Mateo, 1; Santa Inez Mission (Santa Barbara Comity), 2; Santa Monica, 1; Sea- side (Monterey Coimty), 7; Sisquoc (Santa Barbara County), 3; Soledad, 1; Stanford University, 1; Strawberry Peak (San Gabriel Mountains), 1; Sur (Monterey County), 1; Tassajara (Contra Costa County), 1; Temescal (Riverside County), 2; Ventura River, 1; Walnut Creek (Contra Costa Comity), 5; "Wilson Peak (Los Angeles County), 9. CITELLUS BEECHETI DOUGLASII Richardson Douglas's Ground Squirrel (Pis. 8; 26, B; 31, B) Arctomys? (Spermophihts?) douglasii Richardson, Fauna Boreali- Americana, 1 : 172, 1829. Spermophilus douglasii F. Cuvier, Sup. a I'hist. natur. Buffon 1 : 333, 1831. [Spermoplnlus grammurus'] var. douglassi Allen, Boston Soc. Nat. Hist. Proc. 16 : 293, 1874. Citellus V. douglasi Elliot, Field Columb. Mus. Pub., Zool. Ser. 3 : 183, 1903. Citellus 'beecTieyi douglasi Grinnell, Calif. Acad. Sci. Proc. (4) 3 : 345, 1913. 53 Mus. Vert. Zool. ^ Univ. Michigan Mus. Zool. 1938] REVISION OF THE GROUND SQUIRRELS 151 Otospennophilus grammiints dotifflasii Miller, U. S. Natl. Mns. Bull. 128: 180, 1924. Type. — None designated ; description based on a hunter's skin from the "banks of the Cokimbia" [River], sent to E-ichardson by David Douglas. Range. — Western Oregon and northern California, from tlie Colum- bia River Valley south nearly to San Francisco Bay, Calif.; east to the Deschutes River Valley, Oreg. ; Lake City, Calif., and a line reaching from the latter point to Eagle Lake. Lyonsville, Magalia, and Nelson ; from there southward occurring only west of the Sacra- mento River (fig. 14). Zonal range: Mainly Upper Sonoran and Transition; into Lower Sonoran in the Sacramento Valley and into Canadian on the Siskivou Mountains (6,000 feet) and the Scott Mountains (6.800 feet)." Exteimal characters. — Similar in general tone of upper parts to C. h. heecheyi^ but averaging paler, especially on the head; a large triangular black patch on the foreback between the white shoulder patches ; ears paler ; under parts slightly paler ; tail averaging longer, and paler underneath. Compared with C. h. fisheri: Back darker, with a black wedge between the shoulders; tail averaging longer, and deeper buff beneath. Cranial characters. — Skulls of adult males average larger than those of heecheyi while skulls of females average smaller. Color. — Fresh pelage (October) : Nose and face smoke gray, washed with pinkish cinnamon; crown mikado brown or cinnamon; ears fuscous on outer surface, pale cinnamon buff on inner surface; eye ring creamy white ; shoulder patches pale smoke gray, enclosing a wedge-shaped patch of fuscous black; general tone of hinder back near sayal brown, mottled with pale smoke gray or pale pinkish buff; front feet pinkish buff; hind feet varying from cartridge buff to cin- namon buff; tail above, mixed black and pale pinkish buff, the hairs edged with grayish white ; tail beneath, cinnamon buff or light ochra- ceous buff, more or less obscured with grayish white; under parts cartridge buff, pinkish buff, or grayish white. Variation. — Occasional specimens lack the black patch on the back ; in a series of 20 specimens from The Dalles, Oreg., one in fresh pelage lacks the black patch entirely and four in worn pelage have the black nearly obliterated. Molt. — The annual molt takes place usually in June or July, but may sometimes be delayed till August or early September, Certain individuals in spring and early summer become greatly worn before molting, so that the blackish patch on the fore back becomes faded or nearly obliterated. Specimens taken at The Dalles, Oreg., June 10, show new pelage coming in on the head and fore back; female specimens from Still- water, Calif., July 1, and Drew, Oreg. July 28, are in similar condi- tion of pelage; nursing females from Forest (jrove, Oreg., July 16, and Tower House, Calif., August 4, are in badly worn pelage and had not started to molt ; another nursing female, from Chico, Calif., Sep- tember 19, had just acquired a fresh pelage over the anterior half of the back, the hinder back being in worn and faded pelage. Measurements. — Averago of 10 adult males from Oregon: Total length, 476 (450-500) ; tail vertebrae, 207 (190-223) ; hind foot, 61 (56-6Li) ; ear from notch 1 52 NORTH AMERICAN FAUNA [No. 56 (dry), 19.5 (17.5-22). Average of 10 adult females from Oregon: Total length, 450 (440-460) ; tail vertebrae, 193 (182-200) ; hind foot, 58.6 (57-60) ; ear from notch (dry), 18.4 (17-20). Skull: Average of 8 adult males from Oregon: Great- est length, 61.5 (59.2-63.2) ; palatilar length, 30.1 (29.2-31) ; zygomatic breadth, 38.1 (36.3-39.9) ; cranial breadth, 24.5 (24-25) ; interorbital breadth, 14.2 (13.3- 15.7) ; postorbital constriction, 15.1 (14.5-15.8) ; length of nasals, 22 (20.5-23.5) ; maxillary tooth row, 11.5 (11.1-12). Average of 10 adult females from The Dalles, Oreg. : Greatest length, 56.1 (54.6-57.8) ; palatilar length, 26.9 (26-27.8) ; zygomatic breadth, 34.1 (33.2-35.3) ; cranial breadth, 23.1 (22-24) ; interorbital breadth, 12.8 (11.5-13.4) ; postorbital constriction, 15.8 (14.9-16.9) ; length of nasals, 19.3 (18.5-20.6) ; maxillary tooth row, 10.8 (10.1-11.2). Remarks. — Douglas's ground squirrel is closely related to beecheyi, differing chiefly in having a large black patch on the fore- back between the whitish side stripes; the range of douglasii is separated from that of fisheri by the Sacramento River for a con- siderable distance in central California, but in the vicinity of Chico, douglasii crosses to the east side of the river and meets the range of ■fisheri in Butte County. Typical specimens of douglasii have been collected at points nine miles east of Chico and eight miles east of Nelson. At Oroville and Yankee Hill typical fisheri occurs, while at Cherokee and Pentz typical specimens of each and some with inter- mediate characters have been taken. This condition suggests hybrid- ization rather than the usual type of intergradation, but in considera- tion of the close resemblance between the two forms in color and with no important difference between them in skull characters, it seems best to treat them as subspecies. The present species is reported to have crossed the Columbia River and established itself near White Sahnon, Wash., within very re- cent times. In July 1917, W. N. Suksdorft stated that it had come in within the past 2 or 3 years and had already spread for 2 or 3 miles up the river valley. Specimens examined. — Total number, 338, as follows: California: Adin (Modoc County), 7; Bald Mountain (8 miles south, Shasta County), 2; Balls Ferry (Shasta County), 1;" Bartlett Mountain (Lake County), 2; Bear Creek Valley (Shasta County), 1; Beswick (Siskiyou County), 6; Bieber (Lassen County), 1; Branscomb (Mendocino County), 1;°* Burney (Shasta County), 4; Cahto (Mendocino County), 1; Calpella (Mendocino Comity), 1; Cassell (Shasta County), 5; Cherokee (Butte County), 2;'° Chico, 17; Cloverdale, 3; Dana (Shasta County), 3; Davis, 1; Dry Creek (Butte County), 4;" Eagle Lake (Lassen County), 2; Eel River (Humboldt County), 6; Elmira (Solano County), 1; Eureka, 3;" Fairfield, 6; Fall River Mills, 1; Fort Crook (Shasta County), 6; Glen Ellen (Sonoma County), 13; Goose Lake, 3; Guenoc (Lake County), 1; Hayden Hill (Lassen County), 4; Healdsburg, 1; Hoopa Valley (Huml)oldt County), 7; Hornbrook, 3; Mad River (Carson's Camp, Humboldt Bay), 2; Lake Cit.v (Modoc County), 1; Lakeport, 1; Lower Lake (Lake County), 3; Lyonsville (Tehama County), 2; Magalia (Butte County), 1; Merrill- ville (Lassen County), 1; Middletown (Lake County), 1; Mill Creek (east of Lyonsville, Tehama County), 1; Montague, 1; Mount George (Napa County), 1; Mount St. Helena (Sonoma County), 2; Mount Veeder (10 miles N. W. of Napa), 2; Nelson (Butte County), 2; North Yolla Bolly Mountain (12 miles north. Trinity County), 1;°° Paynes Creek (Tehama County), 1; Pentz (Butte County), 4;°' Petaluma, 3; Pittville (Shasta County), 1; Red Bluff, 11; Redding, 5; Redding-Bieber road (12 miles west of Burney), 3; Round Mountain (Shasta County), 1; Saint John (Glenn County), 3; Salt Creek (6 miles northwest of Baird, Shasta County), 1; Salmon Mountains (near Etna Mills, Siskiyou County), 5; Shasta Valley ^ Univ. Michigan Mus. Zool. E« Mus. Vert. Zool. "Field Mus. Nat. Hist 1938] REVISION OF THE GROUND SQUIRRELS 153 (Siskiyou County), 1; Sherwood (Mendocino County), 3; Siskiyou Moun- tains (White Mountain), 7; Sisson (Siskiyou County), 8; Sites (Colusa County), 1; Smith River (Del Norte County), 2; South Tolla Bolly Moun- tain (Trinity County), 1; Stillwater (Shasta County), 2; Tehama, 1; Tower House (near Bally Mountain, Shasta County), 1; Tule Lake (east side), 1; Ukiah, 5. Oregon: Ashland, 3; Beaverton (Washington County), 1; Blaine (Tillamook County), 3;°° Dog Lake Ranger Station (30 miles southwest of Lakeview), 1; Douglas County (22 miles east of Drew), 1; Elk Head (Douglas County), 1; Eugene, 3; Farren Ranger Station (13 miles southwest of Galice), 1; Forest Grove, 11; Fort Klamath, 1;'° Gold Beach, 4;" Grants Pass, 10; Hood River, 4; Klamath Lake, 2; Mapleton (Lane County), 1; Maupin (Wasco County), 8; McCoy (Polk County), 4; McKenzie Bridge (10 miles east. Lane County), 5; Miller (Sherman County), 3; Mount Hood (north slope, 2,800 feet altitude), 1; Naylox (=Algoma, Klamath Lake), 2; Oregon City, 1; Philomath, 3; Portland, 2; Prospect (Jackson County), 6; Reston (Douglas County), 1; Rogue River Valley (near Grants Pass), 4; Roseburg, 5; Salem, 3;" Scottsburg (Douglas Coimty), 1; Siskiyou (Jackson County), 1; The Dalles, 20; Tillamook, 1 ;"* Wapinitia (Wasco County), 1; Warm Springs (Jefferson County), 2; Warm Springs River (Wasco County), 2. Washington: White Salmon, 3. CITELLUS BEECHEYI SIERRAE, sxjbsp. nov. Sierra Ground Squtbrei- Type. — Collected at Emerald Bay. Lake Talioe, Calif., May 23, 1897, by J. Alden Loring; female adult, skin and skull, no. 88421, IT. S. Natl. Mus. (Biological Survey collection) (orig. no. 4166.) Range. — Higher parts of the northern Sierra Nevada, from Plumas County south to Mariposa County (upper Merced River) (fig. 14). Zonal range: Transition and Canadian. External characters. — Similar in size and color of upper parts to C. h. 'beecheyi; sides of head more grayish (less huffy) ; feet more whitish (less huffy) ; under parts averaging paler (more whitish) ; under side of tail more grayish (less huffy). Compared with C. h. fisheri: Head and upper parts distinctly darker; feet more whitish (less huffy) ; tail darker and less huffy beneath. Cram at characters. — Skull similar to that of heecheyi., but aver- aging slightly smaller, except in the postorbital breadth, which ig greater. Color. — Winter pelage (type. May 23) : Head sayal brown, washed with grayish white; sides of face fuscous, the hairs tipped with grayish white; ears fuscous black, shaded on posterior margin with grayish buff; general tone of upper parts pale sayal brown, flecked witii huffy white; sides of neck and shoulders with a heavy wash of grayish white, and sides of body less heavily washed with the same ; hind feet grayish white, front feet pale buffy white; tail above, fuscous black, mixed with grayish white; tail beneath, mixed buffy w^hite and fuscous black; under parts pinkish buff. Variation. — In some specimens, the upper parts are snuff brown, flecked with cinnamon buff and buffy white; the head is sometimes pure sayal brown, without grayish wash. Measurements. — Average of 3 adult males from vicinity of Lake Tahoe (Emerald Bay, Tallac. and Emigrant Gap) : Total length, 452 (44(M70) ; tail vertebrae, 17S (170-100) : hind foot, 57.7 (54-63); ear from notch (dry), 20 •' Ilnlv. Michigan Mus. Zool. "T Field Mus. Nat. Rist. 3^54 - NORTH AMERICAN FAUNA [No. 56 (19-21.5). Average of 10 adult females from Emerald Bay, Dormer, and Little Yosemite: Total length, 422 (400-455) ; tail vertebrae, 172 (159-184) ; hind foot, 56.2 (54-60) ; ear from notch (dry), 20.3 (18.5-2.3). Skull: Average of 5 adult males from Emerald Bay, Blue Canyon, and Emigrant Gap : Greatest length, 58 (56.5-59.5) ; palatllar length, 27.7 (26.5-29) ; zygomatic breadth, 36.7 (34.9- 37.8) ; cranial breadth, 23.5 (22.4^24.6) ; iuterorbital breadth, 14.1 (12.9^15.5) ; postorbital constriction, 16.1 (15.7-17.1) ; length of nasals, 20.9 (20.5-21.9) ; maxillary tooth row, 11.4 (11-11.8). Average of 11 adult females from Emerald Bay, Blue Canyon, and Donner: Greatest length, 56.6 (53.1-59.9); palatllar length, 27 (25-28) ; zygomatic breadth, 34.4 (33.1-36.9) ; cranial breadth, 23.4 (22.7-24.9) ; interorbital breadth, 14 (13.5-15) ; postorbital constriction, 16.2 (15.2-17) ; length of nasals, 20.8 (19.5-21.8) ; maxillary tooth row, 11.1 (10.5-11.7). Remarks. — The Sierra ground squirrel bears a close resemblance to typical heecheyi., but differs in certain minor characters as pointed out above; it might be included with heecheyi except for the fact that their ranges are not contiguous, being separated by the range of -fisheri^ the pale form occupying the San Joaquin and Sacramento Valleys. Intergradation with fisheri occurs in the southern Sierra Nevada and along the lower slopes on the western side of the range. Specimens examiiied. — Total number 39, as follows: California: Big Trees (Calaveras County), 1; Blue Canyon (Placer County), 14; Downieville, 1; Emerald Bay (Lake Tahoe), 5; Emigrant Gap (Placer County), 1; Little Yosemite (Mariposa County), 1; Markleeville (Alpine County), 4; Merced River (near head), 3; Quincy, 1; Summit (=Donner, Placer County), 5; Tallac (Eldorado County), 2; Wawona (south fork Merced River, Mariposa County), 1. CITELLUS BEECHEYI FISHERI Meeeiam Fisher's Ground Sqxjireel Spermophilus heecheyi fisheri Merriam, Biol. Soe. Wash. Proc. 8: 133, Dec. 28, 1893. [Spermophilus fframmurus] fisheri Elliot, Field Columb. Mus. Pub., Zool. Ser. 2: 88, 1901. Citellus variegatus fisheri Elliot, Field Columb. Mus. Pub., Zool. Ser. 3: 211, 1903. Citellus becchciji fisheri Grinuell, Calif. Acad. Sci. Proc. (4) 3: 346, 1913. Otospennophilus grammurus fisheri Miller, U. S. Natl. Mus. Bull. 128: 181, 1924. Type. — Collected on South Fork of Kern River, 3 miles above Onyx, Kern County, Calif., July 6, 1891, by A. K. Fisher; male sub- adult; skin and skull, no.|fff|,'U. S. Natl! Mus. (Biological Survey collection) (orig. no. 741). Range. — Greater part of central California, including the San Joaquin and Sacramento Valleys and the southern Sierra Nevada; north on the eastern side of the Sacramento River to southern Butte County, then northeastward to Susanville; east to the western side of Pyramid Lake, Nev., and to Walker Pass, in the southern Sierra Nevada, Calif. ; south to the Tehachapi Mountains ; west to Cuyama Valley, the Carriso Plain, and the western border of the San Joaquin Valley (fig. 14). Zonal range: Upper Sonoran and Transition. External characters. — Similar in size to C . h. 'heecheyi, but hind feet shorter ; coloration paler, both above and below ; light markings on shoulders more prominent and clearer white. Cranial characters. — Skull similar to that of heecheyi but averag- ing smaller, especially in the females; zygomata less widely expanded. 1938] REVISION OF THE GROUND SQUIRRELS 155 Color. — Smnmer pelage (Kern Valley) : Top of head and face light pinkish cinnamon; sides of face pale smoke gray; a large patch of clear creamy white on each shoulder, this color extending to the middle of the back in two narrow stripes separated by a dark area more or less triangular in shape; rest of upper parts about wood brown in general tone, flecked with patches of creamy white; feet pale buff or buffy white ; tail mixed fuscous black and pmkish buff ; under parts creamy white to pinkish buff'. Winter pelage (Modesto, February) : General tone of upper parts (excepting head) pale smoke gray, faintly washed with pale pinkish buff; under parts pale pinkish buff ; tail mixed fuscous black and pale pinkish buff. Molt. — The annual molt may occur at any time between May and August; an adult male from Modesto, taken May 8, shows new pelage coming in on the head, nape, and fore back; a male taken at JNIilford (Honey Lake), June 20, shows new pelage covering the posterior half of the body, and small areas on the head, shoulders, and fore back; a male from Biggs, Butte County, shows small areas of new pelage on the crown and in the middle of the back, behind the shoulders; a male from Carriso Plain, taken August 1, shows new pelage on the head and a large patch on the hinder back. Measurements. — Average of 7 males (adult and subadult) from Kern River Valley and Walker Basin: Total length, 442 (415H175) ; tail vertebrae, 183 (175- 19S) ; hind foot, 57.6 (54-62) ; ear from notch (dry), 1S.4 (17-2C0. Average of 4 adult females from Kern River Valley: Total length, 407 (390-427) ; tail verte- brae, 162 (155-170) ; hind foot, 52.7 (50-56) ; ear from notch (drv), 18.3 (17- 20). Average of 11 adult males from Modesto: Total length, 457 (433-500) ; tail vertebrae, 107 (140-190) ; hind foot, 60.1 (55-63) ; ear from notch (dry), 19.3 (17.5-21) ; average of 4 adult females from Modesto: 423; 168; 55.4; 17.7. Skull: Average of 4 adult males from Kern River Vallev and Walker Basin: Greatest length, 59.3 (57-60.9) ; palatilar length, 28.7 '(27.5-30) ; xvgomatic breadth, 36.9 (36.0-37.4) ; cranial breadth, 24.2 (23.8-24.7) ; interorbital" breadth, 13.5 (11.5-14.3) ; postorl>ital constriction, 16 (15.2-17) ; length of nasals. 22.2 (21.5-22.8) ; maxillary tooth row, 11.8 (11.7-12). Average of 3 adult females from Kern River Valley: Greatest length. 55.8 (55.6-50) ; ]ialatilar length. 26.5 (26-27) ; zygomatic breadth, 34.2 (33.9-.34.6) ; cranial breadth, 23.1 (22.4-23.5) ; interorbital breadth, 13.7 (13.4-14) ; postorbital constriction. 15.3 (14.6-16) ; length of nasals, 20.1 (19.6-20.8) ; maxillary tooth row, 11.4 (11.1-11.7). Aver- age of 15 adult males from Modesto: Greatest length, 59.5 (55.5-62) ; palatilar length. 29.9 (27.5-31) ; zygomatic breadth. 37.5 (.•^4.2-.3S.9) ; cranial breadth, 23.8 (22.2-24.9) ; interorbital breadth. 14.5 (13..3-16.5) ; postorbital constric- tion, 16 (15-16.9) ; length of nasals, 21.8 (20.2-22.S) : maxillary tooth row, 11.7 (11.1-12.3). Average of 6 adult females from Modesto: Gre.-\test length. .56.3 (55.3-.57.5) ; palatilar length, 27.1 (26-28) ; zygomatic lireadth. 35 (33.8-35.8) ; cranial breadth, 23.4 (22.7-24.8) ; interorbital breadth, 13.7 (12.6-14.7) ; post- orbital constriction, 15.5 (14.6-15.9) ; length of nasals, 20 (19.2-20.7) ; maxillary tooth row, 11.6 (10.9-12.) Remarks. — Fisher's ground squirrel is about the size of heecheyi., but averages decidedly paler in color; it is similar to O. h. parindiis in color, but is distinctly larger. Over its extensive range in botli valley and mountain country it is subject to considerable variation in color, and many individual specimens are scarcely different from some individuals of heecheyi. Intergradation with heecheyi occurs along the western side of the San Joaquin Valley and in the Tehachapi Mountains, with sierrae in tlie foothills of the Sierra Nevada and with douglasii in Butte County. 156 NORTH AMERICAN FAUNA [No. 56 Specimens examined. — ^Total number, 279, as follows : Caifornia: Alcalde (Fresno County), 3; Alila ( =Earlimart, Tulare County), 8; Alta Peak (Kaweah River, Tulare County), 1; Aspen Meadow (Yosemite National Park), 4; Auburn (Placer County), 2; Bakersfield (Smiles north- east), 1," Biggs, 3; Bodflsh (Kern County), 1;" Camp Badger (Tulare County), 1; Cannell Meadow (Tulare County), 1;°* Carbondale (Amador County), 2; Carriso Plain, 5; Claribel (Stanislaus County), 1;°* Colusa (6 miles east), 1; Coulterville, 1; Cuyama Valley (San Luis Obispo County), 2; Dos Palos, 1 ; Dry Creek (Butte County), 1 ; "^ Earlimart, 2 ; ^ Eshom Valley (Tulare County), 1; Feather River Station (Butte County), 2; '* Fort Tejon (Kern County), 13; Fresno 4; Fresno Flat (Madera County), 4; Grabner (Fresno County), 6;^° Greenville (Plumas County), 1; Horse Corral Mead- ows (Fresno County), 1; Jackass Meadow (Tulare County), 1 ; ** Jordan Hot Springs (Tulare County), 1 ; '^ Kern Lake (Tulare County), 1; Kern River (15 miles northeast of Bakersfield), 1; Kern River (Isabella and 12 miles below Bodfish), 4; °* Kern River (South Fork, near Onyx), 12; Kern- ville, 2; La Grange (Stanislaus County), 1; Lemoore, 3; Long Valley (Las- sen County), 1; Los Banos (Merced County), 9; Maricopa, 4;^ Marysville, 1; Marysville Buttes, 7; Milford (Lassen County), 2; Milo (Tulare County), 2; Mineral King (East Fork Kaweah River, Tulare County), 1; Modesto, 31 ; Mono Flats (Santa Barbara County), 2; Mountain House (6 miles south- west of Downieville ) , 2 ; Mount Finos, 7 ; Mount Whitney, 1 ; Nevada City, 2; Orosi (Tulare County), 7; Oroville (Butte County), 1;^ Pacheco Pass (Santa Clara County), 2 ; Placerville (Eldorado County), 3 ; Plumas County, 1; Porterville, 1; Prattville (Plumas County), 2; Raymond (Madera Coun- ty), 2; Redwood Mountain (General Grant National Park), 1 ; Ripon, 2; Rose Station (6 miles north of Old Fort Tejon), 2; Sacramento, 3; Salt Springs (Fresno River, 30 miles east of Raymond), 1; San Emigdio (Kern County), 1; San Emigdio Canyon, 2; San Emigdio Creek, 2; ^ Sierra Valley (Plumas County), 2; Sequoia National Park, 2; Soquel Mill (head of North Fork of San Joaquin River), 2; Sunset Station (near Maricopa, Kern County), 1; Susanville. 1; Taylor Meadow (Tulare County), 5;^ Tehachapi, 2; Teha- chapi Peak, 3; Tejon Canyon, 3; Tejon Pass, 4; Three Rivers (Tulare County), 2; Tipton (Tulare County), 5;°* Tracy, 1; Trout Creek (Tulare County, altitude 6,000 feet), 3 ; '' Trout Meadows (Tulare County), 1 ; Volta (Merced County), 2; Walker Basin (Kern County), 1; Walker Pass (Kern County), 4; Weldon (Kern County), 3; Yankee Hill (Butte County), 1; Yosemite Valley, 3; Zaca Lake (Santa Barbara County), 1. Nevada: Carson City, 1; Genoa, 1; Glenbrook (Douglas County), 3; Pyramid Lake (west side), 4; Reno, 3; Verdi, 6; Virginia Mountains (Washoe County), 1. CITBLLUS BEECHEYI PARVULUS Howell Lessee Califoenla. Ground Squieeel (Pis. 26, A; 31, A) Citellus heecheyi parviilus Howell, Jour. Mammal. 12 : 160, May 14, 1931. Type. — Collected in Shepherd Canyon, Argus Mountains, Calif., April 30, 1891, by A. K. Fisher; female subadult, skin and skull, no. ^^%^, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 569 J. Range. — Desert ranges of southern California (except the Provi- dence Mountains) ; north to Owens Valley; south to the San Jacinto Mountains (fig. 14). Zonal range: Mainly Upper Sonoran and Transition, but extending into Lower Sonoran. Oranial characters. — Similar to O. h. -fislieri^ but smaller. Color. — Not appreciably different from that of -jisheri. =8 Mus. Vert. Zool. ^ Cleveland Mus. Nat. Hist. 1938] REVISION OF THE GROUND SQUIRRELS 157 Measurements. — Average of 10 adult males from Panamiut Mountains, Argus Mountains, and Owens Valley : Total length, 411.8 (383-435) ; tail vertebrae, 162.8 (155-179) ; hind foot, 54.8 (50-58) ; ear from notch (dry), 19.8 (18-21). Average of 12 adult females from same section: Total length, 410 (885-455) ; tail vertebrae, 163 (145-180) ; hind foot, 52.9 (50-56) ; ear from notch (dry), 19 (17-22). Skull: Average of 7 adult males from Panamint Mountains, Argus Mountains, Lone Pine, and Owens Lake: Greatest length, 56.3 (53.9-60.5) ; palatUar length, 26.8 (25-28) ; zygomatic breadth, 35.8 (34-36.4) ; cranial breadth, 23.3 (22.7-24.4) ; interorbital breadth, 12.8 (11.8-13.3) ; postorbital constriction, 14.9 (13.6-16.1) ; length of nasals, 20.9 (19.4-22.2) ; maxiUary tooth row, 11.1 (10.9-11.8). Average of 9 adult females from same region: Great- est length, 53.9 (52.2-54.8) ; palatilar length, 25.4 (25-26) ; zygomatic breadth, 33.6 (32.6-34.7) ; cranial breadth, 23.2 (22.8-24.1) ; interorbital breadth, 13.3 (12.4-14.1) ; postorbital constriction, 15.8 (14.8-16.4) ; length of nasals, 19.4 (18.&-20.8) ; maxillary tooth row, 11.3 (10.8-11.7). Weight. — One old female from Olancha weighed 655 g. Remarks. — ^In the original description of this race, the present writer defined its range as extending southward to the San Pedro Martir Mountains, Baja California; since then, Huey (1931, p. 18) has described the form from northern Baja California as G. h. liudipes^ and as a result of further intensive study of a large series of specimens from the type region of nudipes and from extreme southern California, it seems proper to restrict the name pai^ulus to the small California race as far south as the San Jacinto Mountains, and to refer the series from San Diego County southward to nudipes. Huey objects to the recognition of parvulus on the ground that there is no appreciable difference between specimens from the type locality of fisheri (South Fork of Kern River) and those from the type locality of parvulus (Argus Mountains) ; comparison of the cranial measurements of seven specimens (four males, three females) of fisheri from the type region given on page 155 with the measure- ments of parvulus (above) shows, however, a decided difference in size of the skulls. It is true that the topotype series of -fisheri is slightly smaller in average cranial measurements than the series from the San Joaquin Valley, but the difference in size is much less than between topotypes of fisheri and of parvulus. The present race intergrades with fsheri in the Piute Mountains, with 0. h. beecheyi in the San Bernardino Mountains, and with nudipes in the San Jacinto Mountains. The series from the San Bernardino Mountains is so nearly intermediate between heecheyi and parvulus that it makes little difference which name is applied to it ; in fact, some specimens are practically typical of one race, some of the other. The skulls average smaller than those of heecheyi. The series from the San Jacinto Mountains is likewise intermediate between parvulus and nudipes, but a little nearer parmdus. The skulls average a little smaller than the San Bernardino series. Specimens examined. — Total number, 160, as follows : California: Argus Range (Inyo County), 3; Andreas Canyon (Riverside County), 1;** Banning, 13; Cabazon (Riverside County), 11;°* Cameron (Kern County), 2; Coso (Inyo County), 6; El Ca.sco (Riverside County), 1; Hesperia (San Bernardino County), 2; Independence, 4;*" Independence Creek (6.500 feet altitude), 1; Jackass Spring, Panamint Mountains, 11 ;~ "Little Lake (Inyo County), 2; Little Onion Valley (Inyo County), 1;" Little Cottonwood Creek (Inyo County), 1;°" Lone Pine, 5; Mount William.son (N, E. base), Owens Valley, 3;" Old Camp Independence, "Mus. Vert. Zool. «' Cleveland Mus. Nat. Hist. " Two in Cleveland Mus. Nat. Hist. 158 NORTH AMERICAN FAUNA [No. 56 Owens Valley, 1;" Olancha (Inyo County), 1;*" Oro Grande, 8; Owens Lake, 6 ; Owens Valley, 2 ; Panamint Mountains, 5 ; Piute Mountains, 1 ; Palm Springs, 8; Reclie Canyon (San Bernardino County), 4; Riverside, 1; San Bernardino, 7; San Bernardino Mountains, 15; San Jacinto Mountains, 32;'° Snow Creek (near Wliitewater, Riverside County), 1;^ Victorville, 1."" CITELLUS BEECHEYI NUDIPES HuEY Juarez Ground Squirrei. CiteUvs beecheyi nndlpes Huey, San Diego Soc. Nat. Hist. Trans. 7: 18, Oct. 6, 1931. Type. — Collected at Hanson Laguna. Sierra Jnarez, Baja Cali- fornia, Mexico (latitude 31° 58' north, longitude 115° 53' west; alti- tude 5,200 feet), October 13, 1926, by Frank Stephens; female adult, skin and skull, no. 2015, San Diego Soc. Nat. Hist. Range. — Northern Baja California and extreme southwestern California, including most of the western half of San Diego County (fig. 14), Zonal range: Upper and Lower Sonoran and Transition. External characters. — Similar to C. h. heecheyi but smaller and with paler feet and under parts and more conspicuous shoulder patches; similar in size to C.h. parvulus but darker. Cranial characters. — Skull closely similar to that of parvulus; smaller than those of heecheyi and C. h. fisheri. Color. — Fresh winter pelage (tcpotypes, October) : Head wood brown; shoulder patches grayish white, strongl}'^ contrasted with the color of the back: dorsal area snuff brown, flecked with light pinkish cinnamon: sides more heavily flecked with grayish white; feet cartridge buff; under parts grayish white, faintly washed with pale pinkish buff; tail black, mixed with white or buffy white. Sum- mer pelage (San Pedro Martir Mountains, July) : Dorsal area paler (less brownish) than in winter, the general tone on the back near wood brown, with a pinkish tinge, the sides more grayish. In cer- tain summer specimens in worn pelage — notably one from San Telmo, August 22— the general tone of the dorsal area is near cinna- mon. In some also, the anterior back, between the white shoulder patches, is blackish brown, due in large part to the wearing away of the tips of the hairs and exposure of the dark basal portion. Molt. — A specimen from the San Pedro Martir Mountains, taken June 29, is in badly worn pelage and shows a fresh pelage coming in over the anterior half of the back ; several from Trinidad Valley, taken July 10 to 16, show a fresh pelage on the rump, the rest of the back being much worn. Measurements. — Average of 8 adult males from San Pedro Martir Moun- tains: Total length. 411.6 (386-442) ; tail vertebrae. 177 (162-196) ; hind foot, 56.1 (52-62) ; ear from notch (dry), 18.5 (17-20). Average of 11 adult females from Hanson Laguna, Trinidad Valley, and San Pedro Martir Mountains : Total length, 397 (357-435) ; tail vertebrae. 156.5 (140-186) ; hind foot, 53.7 (50-57) ; ear from notch (dry), 19 (17-20). Skull: Average of 6 adult males from Hanson Lagima. Trinidad Vallev. San Pedro Martir Mountains, and San Telmo: Greatest length, 56.8 (54.859.5); palatilar length, 27 (26-28); zygomatic breadth, 35.2 (32.8-35.9) ; cranial breadth, 23.5 (22.8-24.4) ; interor- bital breadth, 13.7 (11 .-1-14.8) ; postorbital constriction, 16 (15.2-18.1) ; length <=9Mus. Vert. Zool. f^ Cleveland Mus. Nat. Hist. "2 Eighteen in Mus. Vert. Zool. 1938] REVISION OF THE GROUND SQUIRRELS 159 of nasals, 20.4 (1&-21.7) ; maxillary tooth row, 11.2 (10.6-12). Average of 10 adult females from San Pedro Martir Mountains and Hanson Laguna : Greatest length, 54.6 (51.6-56.1) ; palatilar length, 25.8 (23.5-27) ; zygomatic breadth, 34.2 (32.3-35.2) ; cranial breadth, 23 (22.2-24.7) ; interorbital breadth, 13.3 (12.2-14.6) ; postorbital constriction, 16.1 (15.6-17.3) ; length of nasals, 19.5 (17.5-20.6) ; maxillary tooth row, 11.1 (10.4-11.7). Remarks. — This is a small, dark race, nearest in general coloration to heecheyi, but with more conspicuous white shoulder patches and paler under parts. It averages slightly larger in external measure- ments than parvulKS, though the skulls of these two races are closely s-'imilar. Wliere their ranges meet in the mountains of San Diego County, Calif., many intermediate specimens are found. In the series examined from Santa Ysabel, Witch Creek, Twin Oaks, Jacumba, Nachoguero Valley, and Dulzura, some of the specimens are fairly typical of nudipes.^ while others are much paler and might almost as well be referred to parvulus. A large series from San Ysidro Ranch, on the Mexican boundary line, 19 miles east of the Pacific Ocean, are very similar in size and general coloration to nudipes., but have somewhat more buffy under parts, thus showing approach to heecheyi. The series from around San Diego Bay is still more like heecheyi in color, though agreeing with nudipes in smaller size of skull and hind feet. A series of 10 specimens from Point Loma is about as dark on the upper parts as heecheyi but the under parts are decidedly paler. Four specimens from San Diego and one from mouth of Tia Juana River agree both in color and size with typical nudipes except for somewhat more buify under parts. Another individual from Tia Juana River is about as dark as heecheyi, both above and below. Specimens examined. — Total number, 163, as follows: Baja California: Descanso Bay (north side), 1;"^ EI Rayo, Hanson Laguna Mountains, 2 ; Ensenada, 1 ; Hanson Laguna, 1 ; Las Eucinos, 1 ; ~ Nacho- guero Valley (near Monument 2.";7, Mexican boundary line), 5; San Pedro Martir Mountains, 22 (including La Grulla. 2; I'inyon, 2; Rancho San Antonio, 9; Rancho Santo Tomas, 1; Vallecitas, 5); San 'JVlnio, 1; San Quentin, 3;*^ San Matias Pas.s, 1; San Ysidro Rancli (near Monument 250, Mexican boundary line), 15; Tecarte Valley, 1; Trinidad Valley, 6."° California: Campo (San Diego County), 1;"^ Chula Vista, 3;"' Cuyamaca Mountains (San Diego County), 4;" Dulzura (San Diego County), 16; Grapevine Spring (San Diego County), 1;'" Jacumba Springs, 5; Jamul Creek (San Diego County), 1; Julian (San Diego County), 8;*" Laguna Mountains (San Diego County), 16; Lakeside (San Diego County), 2;"' Mountain Spring (4 miles north of Monument 231, ]\Iexican boundary line), 8; Oceanside (San Diego County), 2; Pacific Ocean, at Mexican boundary line, 1; Point Loma (San Diego County), 10;" San Diego, 6; Santa Ysabel (San Diego County). 4: Tia Juana River (mouth). 2; Twin Oak.s ( San Diego ( 'ounty ) , 2 : Warner Pass ( San Diego County) , 3 ; " Witch Creek (San Diego County), 8." CITELLUS BEECIIEYI RUPINARUM Huey Catavina Ground Squirisel Citellus heecheyi rupinarum Huey, San Diego Soc. Nat. Hist. Trans. 7 : 17, Oct. 6, 1931. Type. — Collected at Catavina, Baja California, Mexico (hititude 29°54' north, longitude 114°57' west), October 9, 1930, by Laurence *' Mus. Vert. Zool. •^ San Difigo Soc. Nat. Hist. "Field Mus. Nat. Hist. IgO NORTH AMERICAN FAUNA [No. 56 M. Huey ; female subadult, sMn and skull, no. 8251, San Diego Soc. Nat. Hist. Range. — Deserts of central Baja California, south of the San Pedro Martir Mountains ; southern limits unknown (fig. 14). Zonal range: Lower Sonoran. External characters. — Similar to C. &. nudipes, but paler (less brownish) dorsally and without darker area on anterior back; shoulder patches less prominent; head slightly paler (less reddish). Closely similar to C. h. parvulus., but shoulder patches less distinct and front feet apparently darker buff. Cranial characters. — Skull very similar to that of nudipes., averag- ing slightly smaller and relatively narrower across zygomata. Color. — Winter pelage (Oct. 9) : Head pale wood brown or avel- laneous; shoulder patches grayish white or creamy white; dorsal area sayal brown, flecked with pinkish buff; feet cartridge buff; under parts creamy white, washed with pinkish buff on lower abdo- men ; tail mixed black and pale pinkish buff. Molt. — A specimen from San Fernando, taken September 5, shows patches of new pelage on the top of the head and between the shoul- ders, the remainder of the pelage being moderately worn. A speci- men from Catavina, taken on October 9, has acquired a nearly com- plete new pelage except on the nape and shoulders. Measurements. — Average of 4 adult females: Total length, 421 (415-425) tail vertebrae, 181 (170-188) ; hind foot, 55. Skull: Average of 4 adult females: Greatest length, 54.2 (53.2-55.3); palatilar length, 26.1 (25-27) zygomatic breadth. 32.9 (.32.3-34.5) ; cranial breadth. 22.9 (22.6-23.5) ; inter orbital breadth, 12.2 (11.4-14) ; postorbital constriction, 16.1 (15.7-16.4) length of nasals, 18.9 (18.5-19.4) ; maxillary tooth row 11.2 (10.8-11.6). Remarks. — This pale subspecies is similar in color to parvulus of California; its range is a desert area in Baja California between the ranges of nudipes and C . atHcapillus, both of which are darker in color. No males of this race have been examined and only four females, so that the skull characters and color variations are im- perfectly known. Specimens examined. — Total number, 4, as follows : Baja California: Catavina, 3; " San Fernando, 1. CITELLUS BEECHEYI NESIOTICUS Eixiot Catalina Ground Sqitireel Gitellus nesioticus Elliot, Field Columb. Mus. Pub., Zool. Ser. 3: 263, Mar. 8, 1904. Citellus beecheyi nesioticus Grinnell, Calif. Acad. Sci. Proc. (4) 3: 345, 1913. Otospermophihis nesioticus Miller, U. S. Natl. Mus. Bull. 128: 181, 1924. Type. — Collected on Santa Catalina Island, Calif., February 8, 1903, by John Eowley ; male adult, skin and skull, no. 11722, Field Mus. Nat. Hist. Range. — Catalina Island, Calif, (fig. 14). Zonal range: Upper Sonoran. External characters. — Similar to G. h. heecheyi., but hind foot averaging larger ; coloration very similar, but averaging more gray- ish (less brownish) and light shoulder stripes less conspicuous. «^ San Diego Soc. Nat. Hist. 1938] REVISION OF THE GROUND SQUIRRELS 161 Cranial characters. — Skull similar to that of heecheyi^ but averag- ing larger jnasal branches of premaxillae broader. Color. — Winter pelage (February-April) : Head and face pink- ish cinnamon or grayish white, more or less darkened ^yhen worn by the fuscous bases of the hairs; ears fuscous, broadly bordered on posterior portion with drab; upper parts mixed cinnamon buff and buffy white, darkened by the fuscous bases of the hairs; shoul- ders washed with grayish or buffy white, this wash continuing as an indistinct stripe on each side of the dorsal area to the middle of the body; sides flecked wdth rather large, irregular spots of white or buffy white; tail above, fuscous or fuscous black, mixed with buffy white ; tail beneath, pinkish buff, mixed with fuscous black and edged with pale buff; feet cartridge buff; under parts pinkish buff or warm buff. Variation. — ^The type specimen has a large patch of black on the forehead, this being the only specimen in the series of 18 examined that shows such a marking. Certain specimens in worn winter pelage show a large area of fuscous on the back from the occiput to the middle of the body. Measurements. — Average of 12 adults (4 males, 8 females) from Catalina Island: Total length, 451 (432-476) ; tail verterbrae, 172 (154-188) ; hind foot, 59.1 (5.5-63.5) ; ear from notch (dry), 20.3 (19-21.8). Skull: Average of 4 adult males from Catalina Island: Greatest length, 60.7 (59.1-61.9) ; palatilar length, 29.2 (28-30) ; zygomatic breadth, 38.5 (36.8-40.1) ; cranial breadth, 24.5 (23.5-25.4) ; interorbital breadth, 15.5 (14.9-16) ; postorbital constriction, 15.2 (14.7-15.8) ; length of nasals, 22.6 (21.7-23.5) ; maxillary tooth row, 11.9 (11.8-12). Average of 11 adult females from same locality: Greatest length. 58 (56.9-60.3) ; palatilar length, 27.2 (26-28) ; zygomatic breadth, 36.4 (35-37.5) ; cranial breadth, 23.7 (22.9-24.4) : interorbital breadth, 14.5 (13.5- 15.9) ; postorbital constriction, 15.3 (14.6-16.2) ; length of nasals, 21.2 (20.6-22) ; maxillary tooth row, 11.7 (11.2-12.2). Remarks. — This island form is evidently derived from the stock of the adjacent mainland, from which it has diverged but slightly. Since there is complete intergradation of characters between nesioti- cvs and heecheyi.^ and certain specimens from the two series are prac- tically identical, the island form is treated as a subspecies. Specimens examined. — Total number, 18, from Catalina Island. CITELLUS ATRICAT'ILLUS (Bkyant) Lower C.\ijforma Rock Squirrel Spermophilus granwinrus atricapiUus Bryant, Calif. Acad. Sci. Proc. (2) 2: 26, June 20, 1889. [Citellus variepatus] atricapiUus Elliot, Field Columb. Mus. Pub., Zool. Ser. 4: 150, 1904. Otospermophilus grammurus atricapiUus Miller, U. S. Natl. Mus. Bull. 128: 180, 1924. Type. — None designated; based on 29 specimens from Comondii, Baja California, formerly in the collection of the California Acad- emy of Sciences, but destroyed by fire in 1906, Range. — Southern Baja California, from the Sierra de San Fran- cisco (Lat. 28°) south to Comondu (and possibly farther) (fig. 13). Zonal range: Lower Sonoran. External characters. — Similar to C. heecheyi heecheyi but darker, especially on the head and anterior half of the back ; tail averaging longer. 154970—38 11 IQ2 NORTH AMERICAN FAUNA [No. 56 Cranial characters. — Skull similar to that of heecheyi, but aver- aging slightly smaller. Color. — (Topotypes, winter pelage) : Head fuscous black, spar- ingly sprinkled with pinkish buff; eye ring buffy white; ears fus- cous black, narrowly margined on posterior border with pale buff; anterior half of back fuscous black, the sides of neck and shoulders tipped with buffy white, leaving a well defined dark triangular patch uniting with the color of the head; hairs on posterior back fuscous at base, tipped with pinkish cinnamon and pale pinkish buff; front feet pale buff ; hind feet pinkish buff ; tail mixed fuscous black and pale buff; under parts fuscous, overlaid with pale buff. Afolt. — A specimen from Comondu, September 27, had nearly com- pleted the molt. New pelage had apparently come in from both directions, covering all the body except a small area just behind the shoulders. A female from San Ignacio, October 15, shows new pelage covering the posterior portion of the body almost to the shoulders. Measurements. — Average of 12 adults (7 males, 5 females) from type lo- cality: Total length, 440.4 (410-465); tail vertebrae, 195 (185-210); hind foot, 57.2 (55-60) ; ear from notch (dry), 17.5, 18 (2 specimens). Skull: Aver- age of 9 adults (5 males, 4 females) from type locality: Greatest length, 56.3 (54.8-58.5) ; Palatilar length, 27 (26-28.5) ; zygomatic breadth, 34.5 (33.1-35.7) ; cranial breadth, 23.5 (22.6-24.6) ; interorbital breadth, 13 (12-14) ; postorbital constriction, 16 (15.1-17) ; length of nasals, 20.2 (19.1-21) ; maxillary tooth row, 11.5 (11-12). Remarks. — Although closely related to C. heecheyi., C. atricapillus seems to be a distinct species, distinguished by darker coloration of the head and anterior back. The ranges of the two species are apparently separated by an area of low country about 40 miles in width, where squirrels of this group do not occur. Furthermore, the race of heecheyi occurring nearest to the range of atricapillus is very much paler (less blackish) and decidedly smaller. Specimens examined. — Total number, 38, as follows: Baja California: Comondfl, 22; San Ignacio, 15; ** San Pablo, 11. NOTOCITELLUS, subgenus nov. [Characters and description on p. 44] Key to Species and Subspecies a^. Cheeks tawny. b\ Under parts darker annulatus (p. 163) b'. Under parts paler goldmani (p. 164) a". Cheeks buffy adocetus (p. 165) CITELLUS ANNULATUS (Axtoubon and Bachman) [Synonymy under subspecies] SpecifiG characters. — Size medium, slightly smaller than C. heech- eyi heecheyi; hind foot, 50-&4 mm ; tail, 186-228 ; skull length, 51.6- 57. Skull similar in general to that of heecheyi., but relatively nar- rower across the zygomata, which are less widely expanded at pos- terior end; interorbital breadth relatively greater; upper incisors shorter and thicker (antero-posterior diameter greater). ** Eight in collection San Diego Soc. Nat. Hist. 1938] REVISION OF THE GROUND SQUIRRELS 163 General form similar to that of G . heecheyi heecheyi but somewhat slenderer; ears broader and less pointed; feet and legs slenderer; claws on front feet sharper and more curved; tail nearly or quite as long as the body, distichous, rather narrow, and not bushy, annulated with about 15 blackish bands. CITELLUS ANNULATUS ANNULATUS (Aububon and Bachman) Ring-tailed Geound Sqihebel (Pis. 9; 26, Z); 31, Z)) Spermophilus annulatus Audubon and Bachman, Jour. Acad. Nat. Sci. Phila. 8: 319, 1842. Citellus annulatus Merriam, Biol. Soc. Wash. Proc. 16: 79, 1903. Otospermophilus annulatus Miller, U. S. Natl. Mus. Bull. 128: 180, 1924. Type. — Not designated by number; the type specimen, without as- signed locality, was purchased from a dealer by S. F. Baird and presented to Audu- bon (Baird, 1857, p 327) ; type locality hereby fixed at Manzanillo, Colima, Mexico. Range. — Colima and northern Guer- rero, Mexico; prob- ably also coastal re- gion of Michoacan (fig. 15). Zonal range : Entirely Tropical. Characters. — As given under specific characters. Skulls of females average larger than those of males. Color. — Upper parts, including head, nearly uniform mixed fuscous black and cinnamon buff or pale pinkish buff, the blackish color often predominating on the head and sometimes on portions of the back; chin, throat, and sides of nose and face ochra- ceous buff; sides of neck, shoulders, and fore limbs hazel; ears and hind legs hazel or tawny ; under parts warm buff or pinkish buff; tail above, mixed pinkish buff and black ; tail beneath, hazel. Measurements. — Average of 8 adult males from Manzanillo, Colima : Total length, 439 (410-470) ; tail vertebrae, 213.4 (187-228) ; bind foot, 58 (54-64) ; ear from notch (dry), 14.0 (14-1(V). Average of 9 adult females from Manzanillo: Total length, 433.5 (390^70); tail vertebrae, 216.4 (193-238); hind foot, 57.1 (54-60); ear from notch (dry), 15.4 (14-18). Skull: Average of 7 adult males from Manzanillo: Greatest length, 53.6 (51.6-55.8) ; palatilar length, 25.2 (24-26.4) ; zygomatic breadth, 30.5 (28.5-32.2) ; cranial breadth, FiGUUK 15. — Distribution of the subspecies of Citellus an- nulatus: 1. C. a. goldmani; 2, O. a. annulatus. 2g4 NORTH AMERICAN FAUNA [No. 56 21.8 (21.2-22.8) ; interorbital breadth, 13.7 (13.3-15.2) ; postorbital constric- tion, 14.4 (13.9-14.9) ; length of nasals, 17.8 (15.9-19.3) ; maxillary tooth row, 10 (9.6-10.3). Average of 5 adult females from ManzaniUo: Greatest length, 55.4 (54^57) ; palatilar length, 25.5 (25-26.2) ; zygomatic breadth, 31.2 (30.4- 32.6) ; cranial breadth, 22.1 (21.1-23) ; interorbital breadth, 14.5 (13.6-15.3) ; postorbital constriction, 14.3 (13.3-14.8) ; length of nasals, 18.3 (18-18.8) ; maxillary tooth row, 9.9 (9.5-10.2). Remarks. — The original specimen on which the species was based was purchased from a dealer and was supposed to have come from the "western prairies" (Audubon and Bachman, 1851, p. 215). Baird (1857, p. 327), however, considered it to be an African species, of Sciurus and therefore eliminated it from the list of North American mammals. Allen (1877, p. 886), having seen a skin taken by Xantus on the plains of Colima, restored the species to the North American list, assuming (in the absence of a skull) that it belonged in the subgenus Otospermo'philus. Both Bachman and Allen noted the resemblance of this animal in some of its characters to the tree squirrels {Sciurus). E. W. Nelson and E. A. Goldman, on their first trip to Mexico in 1892, obtained 26 specimens in the State of Colima, and this fine series has provided the material necessary for the present study of the species. This species and G. adocetus are the only ground squirrels, excepting G. insulai^s, that are strictly tropical in their range. The original description differs in some details from the speci- mens in hand. Bachman says : "On the under parts, the chin, throat, belly, and inner surface of the legs and thighs are white", whereas all the specimens examined have these parts ochraceous buff or warm buff, except that in a few the belly is buffy white. Specimens examined. — Total number, 30, as follows: Colima: Armeria, 2; Colima, 3; Hacienda San Antonio (at base of Volcano of Colima), 1; ManzaniUo, 20. Guerrero: El Naranjo, 3; La Union, 1. CITELLUS ANNULATUS GOLDMANI (Mebeiam) GrOiLDMAN'S GrOTTND SqUIBREL SpermopMlus annulatus goldmani Merriam, Biol. Soc. Wash. Proc. 15: 69, Mar. 22, 1902. Citellus annulatus goldmani Miller and Rehn, Boston Soc. Nat. Hist. Proc. 31 : 74, 1903. OtospermopMlus annulatus goldmani Miller, U. S. Natl. Mus. Bull. 128: 180, 1924. Type. — Collected at Santiago, Nayarit, Mexico, June 18, 1897, by E, W. Nelson and E. A. Goldman; female adult, skin and skull, no. 91259, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 11223) . Range. — Known at present only from the southern part of the State of Nayarit on the west coast of Mexico (fig. 15). Zonal range: Tropical. External characters. — Similar to typical G. a. annulatus., but hind foot shorter; upper parts averaging darker (more blackish) and under parts paler ; tawny color on sides of head and neck paler and less extensive ; hind legs less tawny and more mixed with blackish. Cranial characters. — Skull closely similar to that of annulatus. 1938] REVISION OF THE GROUND SQUIRRELS 165 Color. — Upper parts fuscous black, sprinkled with ocliraceous buff ; sides of head and neck, and fore limbs ocliraceous tawny ; sides of body warm buff, mixed with fuscous black; hind limbs tawny above, the thighs mixed with fuscous black; throat and under side of hind limbs ocliraceous buff ; belly pale pinkish buff ; tail beneath, tawny ; above, as in annulatus. Measurements. — Average of 6 adult females from Nayarit : Total length, 415 (383-430) ; tail vertebrae, 204 (186-216) ; bind foot, 51.7 (50-54) ; ear from notch, 15.2 (14.5-15.5). Sktill: Average of 5 adult females from Nayarit: Greatest length, 53.5 (51.&-55.4) ; palatilar length, 25 (24-26) ; zygomatic breadth, 30.4 (29-32.1) ; cranial breadth, 22.2 (21.&-23.1) ; iuterorbital breadth, 13.5 (13-14.1) ; postorbital constriction, 15.2 (14.5-15.8) ; length of nasals, 17.5 (16.8-18.5) ; maxillary tooth row, 9.7 (9.3-10.1). Remarks. — Goldman's ground squirrel is a slightly darker race of C annulatus, occupying an area to the northward of the typical subspecies. Specimens examined. — Total number, 6, as follows : Nayarit: Arroyo de Juan Sanches (about 40 miles southwest of Compostela), 1; Compostela, 1 ; San Bias, 2 ; Santiago, 2. CITELLUS ADOCETUS Mebeiam Lessee Tbopical Gbound Sqtjibrel (Pis. 27, E; 32, E) Citellus adocetus Merriam, Biol. Soc. Wash. Proc. 16: 79, May 29, 1903. Otospermophilus adocetus Miller, U. S. Natl. Mus. Bull. 128 : 179, 1924. Type. — Collected at La Salada, 40 miles south of Uruapan, Miclioa- can, Mexico, March 17, 1903, by E. W. Nelson and E. A. Goldman ; female adult, skin and skull, no. 126129, U. S. Natl. Mus. (Bi- ological Survey col- lection) (orig. no. 16183). Range. — Southern Michoacan and northern Guerrero (fig. 16). Zonal range : Tropical. External charac- ters.— Similar to C. annulatus but small- er and paler (less reddish) ; tail with- out annulations. Cranial c h ar ac- ters. — Skull similar in shape and denti- tion to that of annulatus but much smaller; rostrum shorter and broader; iuterorbital region relatively broader; variation in size is considerable; -the largest skull in the series is of a female. Color. — TF<97*n pelage (March) : Hairs on upper parts fuscous at base, tipped with pale pinkish buff or cream color; sides of head and FionRE 16. — Distribution of Citellus adocetus. IQQ NORTH AMERICAN FAUNA [No. 56 neck irregularly blotched with ochraceous tawny; front legs pink- ish buff or cinnamon buff; hind feet cinnamon buff, the thighs ochraceous tawny; tail fuscous or fuscous black, mixed with pale pinkish buff or buffy white, the hairs showing three dark bands when viewed from beneath, but without annulations above; under side of tail shaded with ochraceous tawny toward the tip; under parts pinkish buff or warm buff. Measurements. — ^Average of 14 adults (10 males, 4 females) from type locality : Total length, 335.3 (315-3,53) ; tail vertebrae, 154.6 (138-168) ; hind foot, 46.4 (43^8) ; ear from notch, 14 (13-15). Skull: Average of 11 adults and subadults (6 males, 5 females) : Greatest length, 43.6 (41.6-46.2) ; palatilar length, 20.4 (19-22) ; zygomatic breadth, 24.6 (23.1-26.2) ; cranial breadth, 19.2 (18.3-20.1) ; interorbital breadth, 11.9 (11.5-13.8) ; postorbital contriction, 13.4 (12.6-14.3) ; length of nasals, 13.5 (11.1-14.7) ; maxillary tooth row, 8.7 (7.7-9.2). Remarks. — This ground squirrel, although clearly rather closely related to annulatus, differs from it in many important characters of both skin and skull. It occupies a somewhat more arid district, farther from the coast than does annulatus. The ranges of the two nearly meet and possibly overlap in northern Guerrero. Like an- nulatus., the range of this species is entirely within the Tropics. Specimens examined. — Total number, 36, as follows : Guerrero: La Escondida (about 20 miles southeast of Balsas), 1. Michoacan: La Huacana, 2; La Salada, 32 ; Volcan JaruUo, 1. Subgenus AMMOSPERMOPHILUS Merriam [Cranial characters on p. 44] EXTERNAL CHARACTERS Upper parts nearly uniform, varying from pinkish buff, vinaceous buff, pinkish cinnamon, or vinaceous cinnamon, to wood brown, army brown, fawn, drab gray, or mouse gray ; a narrow, white longitudinal line on each side of the back, from the shoulders to the rump; tail above, mixed black and white, similar beneath, or with a broad white or buffy median area. PELAGE AND MOLT The winter pelage is dense and soft, the summer pelage shorter and more wiry. The bases of the hairs are plumbeous, succeeded by a rather broad whitish or buffy area, then a narrow brownish area, and tipped with white, or varying shades of buff, cinnamon, and gray. The squirrels of this group have two molts annually; the spring molt takes place between the middle of April and early July — usually in May or June — and begins ordinarily on the head and shoulders, but sometimes in patches all over the back. The fall molt occurs from about the middle of September to the last of October, and pro- ceeds from the rump and flanks forward. Several specimens of Citel- lus leuxiurus peninsulae from Baja California are unusual in having a fresh pelage coming in on the hinder parts, between August 8 and 23. 1938] REVISION OF THE GROUND SQUIRRELS 167 Ket to Species and Subspecies o.* Under side of tail with median area white. J)} Tail hairs with two black bauds. c.^ Upper parts more buffy (pinkish buff to wood brown) nelsoni (p. 182) c/ Upper parts less buffy (vinaceous cinnamon to army brown or drab gray). d.^ Upper parts drab gray interpres (p. 180) d.' Upper parts not drab gray. e.^ Anterior upper premolar absent or rudimentary- insularis (p. 181) e.^ Anterior upper premolar present. f.^ Smaller and paler canfieldae (p. 178) f.^ Larger and darker. g} Rump and thighs army brown penhnulae (p. 176) g? Rump and thighs vinaceous cinuamon cxtimus (p. 179) 6.^ Tail hairs with one black band, c* General tone of upper parts vinaceous cinnamon. d.^ Upper parts light vinaceous cinnamon pennipcs (p. 175) d.^ Upper parts vinaceous cinnamon. e.^ Back darkened with fuscous tersus (p. 173) e.^ Back not darkened with fuscous cinnamomeus (p. 174) c.^ General tone of upper parts pinkish buff leucurus (p. 170) a.^ Under side of tail without median white area. &.* Colors darker han-isH (p. 167) 6.* Colors paler saxicola (p. 169) CITELLUS HARRISII (Audubon and Bachman) [Synonymy under subspecies] Specific characters. — Size about as in the larger races of 0. leucurus^ but tail averaging longer, 74-91 mm; hind foot, 38-42; skull length, 38.2^1.2. Skull closely similar to that of C. leucurus cinnamomeus. Upper parts in summer pinkish cinnamon, more or less darkened with fuscous; in winter, mouse gray; tail above and below, mixed black and white (lacking the clear white under surface of leucurus). CITELLUS HARRISII HARRISII (Audubon and Bachman) Gray-tailed Antelope Squirrel (PI. 10) Spermophilus harrisii Audubon and Bachman, Quad. North Amer. 3 : 267, 1854. Tamias harrisi Merriam, North Amer. Fauna 2 : 19, 1889. Anisonyx {Ammospermophilus) harrisii Allen, Amer. Mus. Nat. Hist. Bull. 7: 240, 1895. [Citellus] harrisi Elliot, Field Columb. Mus. Pub., Zool. Ser. 4 : 141, 1904. Ammospermophilus harrisii Moarns, U. S. Natl. Mus. Bull. 56 : 303, 1907. Type. — None designated; description based on a specimen presented lo Audubon by Edward Harris, supposed to have been collected by John K. Townsend, but locality unknown. The type locality is hereby fixed in the Santa Cruz Valley, Ariz., at the Mexican boundary line.^^^ Range. — Greater part of southern, central, and northwestern Ari- zona; north to the Colorado liiver, west of longitude 113°; east to southwestern New Mexico (Hidalgo County) ; south to southern Sonora (Ortiz) ; west to Quitobaquito, on the Mexican boundary line (fig. 17). Zonal range: Lower Sonoran. "«» Meains (1896, p. 444), in (Inscribing the subspecies saxicola, restricted the name harrisii "to the darljcr form, which was found in the Elevated Central Tract, along the .Mexican boundary line, from the Santa Cruz Valley westward as far as Uw Sonoyta * ♦ *." 168 NORTH AMERICAN FAUNA INo. 56 External characters. — Similar to G. leucurus leucurus but larger and slightly darker; tail longer and darker, the under surface mixed black and white (never clear white). Compared with G. I. cinna- TTbomeus: Coloration in winter pelage much more grayish (less vina- ceous) ; in summer pelage darker and less vinaceous; tail longer and darker beneath. Granial characters. — Skull similar to that of leucurus and of cin- namoTneus, but averaging larger. Golor. — Winter pelage: General tone of upper parts mouse gray, the hairs fuscous subterminally, conspicuously tipped with white; head and face vinaceous buff or fawn color; shoulders and thighs vinaceous fawn; front legs and feet vinaceous cinnamon; hind feet light vina- ceous cinnamon, the toes pinkish buff; tail above and below, mixed black and white, the hairs with a broad subterminal band of black and a narrower black band near the base. Sum- mer pelage: Upper parts nearly uniform light pinkish cinna- mon, clearest on the shoulders and thighs, somewhat darkened with fuscous on the back. Molt. — The spring molt occurs in May; specimens taken May 13, 16, and 19, re- spectively, are in badly worn condi- tion, with new hair occurring in patches all over the body. Measurements. — Average of 12 adults (9 males, 3 females) from Tucson and Oracle, Ariz. : Total length, 233.8 (225-250) ; tail vertebrae, 82.7 (74^94) ; hind foot, 39.7 (38-42). Skull: Average of 8 adult males from Tucson and Santa Rita Mountains: Greatest length, 40 (38.8-41.2) ; palatilar length, 18.3 (17-19) ; zygomatic breadth, 23.4 (22.8-24.7) ; cranial breadth, 19.1 (18.6-19.5) ; interor- bital breadth, 9.9 (9-10.8) ; postorbital constriction, 14.4 (13.9-14.9) ; length of nasals, 13.1 (12-13.5) ; maxillary tooth row, 7.2 (6.8-7.5). Average of 7 adult females from Tucson, Phoenix, and Roosevelt Lake : Greatest length, 39.4 (38.4-39.9) ; palatilar length, 18.1 (18-18.5) ; zygomatic breadth, 23 (22.1-23.7) ; cranial breadth, 19 (18.5-19.8) ; interorbital breadth, 9.8 (9.4-10.5) ; postor- bital constriction, 13.7 (13.1-14.5) ; length of nasals, 12 (11.5-12.7) ; maxillary tooth rovr, 7.4 (7-7.8). Weight. — Three specimens weighed, respectively, 112, 122, and 139 g. Figure 17. — Distribution of Citellus interpres, C. in^ularis, and C. nelsoni and of the subspecies of G. leucurus and C. harrisii (subgenus AvimospermopMlvs) : 1, C. I. leucu- rus; 2, C. I. pennipes ; 3, G. I. cinnamomeus ; 4, G. I. tersus; 5, G. I. peninsulae; 6, C. I. canfleldae ; 7, G. I. ex- timus; 8, G. insularis; 9, G. h. samicola; 10, G. h. harrisii; 11, G. interpres; 12, C. nelsoni. 1938] REVISION OF THE GROUND SQUIRRELS IgQ Remarks. — Described by Audubon and Bachman in 1854, this re- mained the only recognized species of the group until 1889, when Merriam separated leucurus^ which up to that time had been con- fused with harrisii. It seems remarkable that a species so distinct as this should occupy an area in the middle of the range of the group, and separated from its congeners by no seemingly effective barriers, at least to the eastward. No reason is apparent why either harrisii or 0. interpres should not occupy southwestern New Mexico, but so far as known, there is a considerable gap in that region between the ranges of these two species. On the west and north, the Colorado River with its deep canyon has proved to be effective in separating the ranges of harrisii and leucurus. Specimens examined. — Total number 217, as follows : Arizona: Baboquivari Mountains, 1; Beale Spring (near Kingman), 6; Big Sandy Creek (Moliave County), 5; Camp Verde (Yavapai County), 16; Congress Junction, 7; Coyote Mountains (Pima County), 1; Dolan Spring (12 miles nortliwest of Chloride), 14; Fish Creek (Maricopa County), 4; Fort Bowie, 9; Fort Mohave, 5; Gila Mountains (Graham County), 2; Graham Mountains (Pinaleno Range), 1; Gold Basin (Mohave County), 3; Gold Road (Mohave County), 3 ; ** Hackberry (Mohave County), 1 ; Harqua- hala Mountains, 1; H-Bar Ranch (Gila County, 10 miles south of Payson), 2; Indian Oasis (Pima County), 1; Kingman, 3;'° Kirkland (Yavapai County), 4; Klondyke (Graham County), 2; La Oso (Pima County), 1; Little Meadows (east side Black Mountains, Mohave County), 6; Mammoth (Pinal County), 1; Maricopa County (20 miles southwest of Phoenix), 2;" McMillenville (Gila County), 1; Mineral Park (Mohave County), 4; Monte- zuma Well (Yavapai County), 4; Mud Spring (18 miles northwest of King- man), 7; New River (Maricopa County), 4; Oatman, 1;'" Old Searchlight Ferry, Colorado River, 1 ; Oracle (Pinal County), 15 ; Peach Springs (Mohave County), 3; Phoenix, 7; Pima County (30 miles south of Tucson), 14;'^ Quitobaquito (Pima County), 5; Rice (Gila County), 1; Roosevelt (17 miles east), 1; Roosevelt Lake, 3; Salt River (12 miles north of McMillenville), 1; Salt River Mountains, 2;'^ Santa Catalina Mountains (mouth of Bear Can- yon), 2; Santa Rita Mountains (north base), 4; Sheldon (Greenlee County), 2; Superior, 2; Tucson, 16; Turkey Creek (east base of Bradshaw Moun- tains, Yavapai County), 5; Vail (Pima County), 2;®° Vulture (20 miles southwest of Wickenburg), 1; Wickenburg, 1. New Mexico: Animas (12 miles northwest, Grant County), 1. Sonora: Hermosillo, 1; Magdalena, 3; Ortiz, 1; Poso de Luis (5 miles south of Monument 152), 1. CITELLUS HARRISII SAXICOLA (Meabns) Yuma Antbxopb Sqihrrel Spermophilus harrisii saxicolus Mearns, U. S. Natl. Mus. Proc. 18 : 444, May 28, 1896 (advance sheet published March 25, 1896). iCitellus (Spermophilus) harrisi] saxicola Elliot, Field Columb. Mus. Pub., Zool. Ser. 4: 142, 1904. Ammospermophilus harrisii saxicola (Mearns), U. S. Natl. Mus. Bull. 5^^ fe- 1907. , length, Ammospermophilus harrisii kinoensis Huey, San Die.';;,-; ;' v.iiiiliEJT'<9*'eadth, 18.4 352, 1937 (Bahia Kino, Sonora, Mexico). , postorbital constriction, 13.9 7'y^^e._Collected at T' - •---' ' maxillary tooth row, 6.7 (6.1-7). Ariz., February 16, 18iTy extensive rancre this race shows relativelv and skull, no. 59869, Us from southeastern Oregon appears slightly 'rom the type region, but the differences are 7oii'n7*'''lV'^u^^"^- ^/^^- "'^V-n by name. Intergradation with C. I. cinna- '" Univ. Michigan Mus. S5oo' A , tt, ii^i t j. j. js "Kansa.s Univ. Mus. Nafi Southwestern Utah and the adjacent parts or « Field MU.S. Nat. iiist3 of eight specimens from St. George, Utah, some are like typical leucurus and others almost like 170 NORTH AMERICAN FAUNA • [No. 56 Range. — Southwestern Arizona and northwestern Sonora, from the Colorado River east to about longitude 113° (fig. 17). Zonal range: Lower Sonoran. External characters. — Closely similar to G. h. harrisii but averag- ing paler on the head, back, shoulders, and thighs. Cranial characters. — Skull very similar to that of harrisii but averaging slightly smaller. Color. — Winter pelage: General tone of upper parts smoke gray, varying to light cinnamon drab, the hairs conspicuously tipped with white ; head, face, shoulders, and thighs vinaceoiis buff ; otherwise as in harrisii. Summer pelage: General tone of upper parts vinaceous fawn, somewhat darkened by the fuscous bases of the hairs, the white tips mostly worn off. Measurements. — Average of 11 adults (6 males, 5 females) from type lo- cality: Total length, 234 (222-245); tail vertebrae, 86.2 (81-92); Mnd foot, 39.3 (38-41). Skull: Average of 12 adults (8 males, 4 females) from type lo- cality: Greatest length, 39.4 (38.2-40.3); palatilar length, 17.8 (16.5-18.8); zygomatic breadth, 23 (22.3-23.6) ; cranial breadth, 18.9 (18.6-19.3) ; interor- bital breadth, 9.6 (9.1-10.7) ; postorbital constriction, 13.7 (12.4-14.2) ; length of nasals, 12.4 (11.3-13.8) ; maxillary tooth row, 6.9 (6.6-7.5). Specimens examined. — Total number 65, as follows: Arizona: Ajo (10 miles north, Pima County), 6; Castle Dome (Yuma County), 2; Gila Mountains (Yuma County), 1; Granite Mountains (near Monu- ment 187), 2; Parker (Yuma County), 5; Quartzsite (Yuma County), 1; Tinajas Altas (Yuma County), 15; Tule Wells (Yuma County), 3; Vicks- burg (Yuma County), 6; Yuma, 12. Sonora: Bahia Kino, 6; '"" Porto Libertad, 6."'* CITELLUS LEUCURUS (Meeeiam) [Synonymy under subspecies] Specific characters. — Size of C. harrisii or somewhat smaller ; hind foot, 85-43 mm; tail, 54-87; skull length, 37-41.8. Skull essentially like that of harrisii^ but smaller in some races. General tone of upper parts varying in summer pelage from pinkish cinnamon or vinaceous cinnamon to cinnamon drab, fawn color, or army brown, the hairs more or less tipped with white or buffy white ; in winter pelage more grayish, drab gray or mouse gray; tail broadly white or whitish below, bordered with fuscous black. CITELLUS LEUCURUS LEUCURUS (Mebeiam) White-tailed Antelope Sqtjibeel (Pis. 10; 27, F; 32, E) ^^^^^'^(iDMlus harrisii Baird, Mamm. North Amer., p. 313, 1857 (not of Audubon ^?om"rtS''l""(ii8-North Amer. Rodentia. p. 810, 1877 (not Spenno- bital breadth, 9.9 (9-10.8) ; postorbi&fi'ei^-^^.i.ctxoi . nasals, 13.1 (12-13.5) ; maxillary tooth rov?, 7.2 (6";^i°^y- „_ ^g„„ females from Tucson, Phoenix, and Roosevelt L, r « * VJ . oVn ' -lono (38.4-39.9) ; palatilar length, 18.1 (18-18.5) ; zygom^,^- ^e^. ^^±^%f^J|i -.qos cranial breadth, 19 (18.5-19.8); interorbital brea "b., Zooi. Ser. d. ^41, lyud bital constriction 13.7 (13.1-14.5) ; length of nasah ^ tooth row, 7.4 (7-7.8). - ' Weight. — Three specimens weighed, respectively. 111,. 1938] REVISION OF THE GROUND SQUIRRELS 17X Type. — Collected in San Gorgonio Pass, Kiverside County, Calif., May 16, 1885, by Frank Stephens; male adult, skin and skull, no. 186466, U. S. Natl. Mus. (-Hif , Merriam collection) (orig. no. 68). Range. — Desert regions of southeastern Oregon, southwestern Idaho, Nevada, western Utah, southeastern California, and north- eastern Baja California; north to northern Malheur County, Oreg., and the Snake Kiver Valley, Idaho ; east to the Sevier Eiver Valley, Utah; south to San Felipe Bay, Baja California; west to the Mohave Desert, Calif, (fig. 17). Zonal range: Upper and Lower Sonoran. External characters. — Similar in color to O. harrisii harrisii but upper parts and limbs paler, especially in winter pelage ; tail shorter and pure white instead of grizzled gray beneath. Cranial characters. — Skull closely similar to that of harrisii but averaging slightly smaller. Color. — Summer pelage: Head and upper parts vinaceous buff; eye ring and lateral stripes white ; front and hind limbs light pinkish cinnamon, shading to buffy white on the feet ; tail above, mixed black and white, except at the base, where it is like the body color; tail beneath, clear creamy white, with a subterminal band of black on the -sides and tip; under parts white or buffy white. 'Winter pelage (November) : Hairs on median dorsal area white at the tips, with a subterminal band of fuscous, producing the general tone effect of drab gray or pale drab gray, shading to vinaceous buff on the head and fore legs ; hind legs vinaceous cinnamon. Molt. — The spring molt may begin as early as the middle of April or be deferred until July. A specimen taken in the Panamint Moun- tains, Calif., April 16, is in much worn pelage, but shows new pelage coming in on the head and fore back ; one from Granite Creek, Nev., May 18, is in a similar condition of molt; two specimens from Cabazon, Calif., May 30 and June 2, show fresh pelage appearing in patches all over the upper parts from nose to root of tail. A female from Walker Pass, Calif., June 21, had just be^un to molt on the head and fore back; a badly worn female specmien from the San Jacinto Mountains, Calif., July 6, shows new hair coming in in patches all over the body. The fall molt takes place in September or October, commencing on the tail and hinder part of body ; a speci- men from Whitewater, Calif., September 13, shows new winter pelage covering the posterior half of the body; one from Antelope Valley, Los Angeles County, Calif., October 17, had completed the fall molt except on the head. Measuretnents. — Average of 10 adults (5 males, 5 females) from type locality: Total length, 216.3 (211-22.3) ; tail vetebrae, 67.5 (^3-71) ; hind foot, 38.3 (37- 40) ; ear from notch, 9 (8.5-10). Skull: Average of 11 adults (8 males, 3 fe- males) from type locality: Greatest length, 3S.S (.37.3^0); palatilar length, 17.6 (16.8-18.5) ; zygomatic breadth, 22.6 (21.7-23.5) ; cranial breadth, 18.4 (17.8-19.3) ; interorbital breadth, 9.7 (8.8-10.4) ; postorbital constriction, 13.9 (13.1-14.9) ; length of nasals, 11.4 (10.7-12) ; maxillary tooth row, 6.7 (6.1-7). Remarks. — Over its very extensive rancre this race shows relativelv little variation. A series from southeastern Oregon appears slightly darker than the series from the type region, but the differences are too slight for recognition by name. Intergradation with C. I. cinna- m,omeus takes place in soutJiwestern Utah and the adjacent parts of Arizona. In a series of eight specimens from St. George, Utah, some of the specimens are like typical leucurus and others almost like l'J2 NORTH AMERICAN FAUNA [No. 56 typical cinnamomeus. One from Canaan Spring, Utah, agrees in color with leucurus, but has a large skull like that of cinnamomeus. This species was confused with harrisii by all writers prior to 1889, when Merriam pointed out its characters and named it. Specimens examined. — Total number, 584, as follows: Arizona: Beaverdam ( =Littlefiel(l, Mohave County), 1; Grand Wash (8 miles south of Pakoon Spring, Mohave County), 2; Wolf Hole (6 miles north, Mohave County), 2. Baja California: San Felipe, IS;''"" San Felipe Bay, 1; San Pedro Martir Mountains, 4. California: Amedee (Lassen County), 1; Antelope Valley (Los Angeles County), 1; Argus Mountains, 6; Banning, 4; Barstow, 17; Beckvpith Pass (Lassen County), 2; Benton (Mono County), 1;" Bergmann's (25 miles east of Temecula, Riverside County), 1;''* Bishop (8 miles west), 1; Borax Flat ( San Bernardino County), 3; Cabazon (Riverside County), 29; Chucka walla Spring (Riverside County), 1; Coast Range Mountains (east base, 5 miles north of Monument no. 230), 7; Colorado Desert, 1; Colorado River (oppo- site Parker, Ariz.), 5; Coso (Inyo County), 13; Coso Mountains, 2;'" Dag- gett (San Bernardino County), 1; Darwin (Inyo County), 1;" Deep Spring Valley (Inyo County), 1; Emigrant Spring, Panamint Mountains, 1; Funeral Mountains, 1 ; Furnace Creek Ranch, Death Valley, 1 ; Goffs ( San Bernardino County), 6; Granite Wells, Mohave Desert, 2; Hesperia (San Bernardino County), 1; Hodge (San Bernardino County), 1; Independence (Inyo County), 1:^* Inyo Mountains, 7;"'^ Ivanpah (San Bernardino County), 4; Jacumba (San Diego County), 1; Kearsarge Pass, 1;'^ Keeler, 6; ■''"Kern River Valley (near Kernville), 1; Little Lake (Inyo County), 1 ;" Little Owens Lake, 1 ; Lone Pine, 8 ; Lone Willow Spring ( San Bernar- dino County), 9; Long Valley (Lassen County), 1; Lower Alkali Lake (Modoc County), 2; Ludlow (San Bernardino County), 2; Mohave, 26; Mohave Desert, 7; Mountain Spring (4 miles north of Monument no. 231, San Diego County), 14; Needles, 11; Onyx (Kern County), 20; Oro Grande (San Bernardino County), 10; Owens Valley, 6; Owens Lake, 5; Palm Springs, 5; Panamint Mountains, 42; Panamint Valley, 4; Providence Mountains, 3; Radec (12 miles east of Temecula, Riverside County), 5; Resting Springs (Inyo County), 15; Saline Valley (Inyo County), 1; Salt Wells Valley (Death Valley), 2; San Felipe River (San Diego County), 4 ; San Felipe Canyon, 1 ; San Gorgonio Pass, 7 ; San Jacinto Mountains (Oak Valley), 1; Secret Valley (Lassen County), 2; Shoshone (Inyo County), 1;" Smoke Creek (at head, Lassen County), 1; Twelve Mile Spring (12 miles north of Resting Springs), 1; Vallecito (San Diego County), 2; Victorville, 3; Walker Pass (Kern County), 4; Weldon (Kern Coimty), 1;" Whitewater (Riverside County), 4. Idaho : Glenns Ferry, 2 ; Murphy, 1. Nevada: Alamo, Lincoln County, 1;'^ Ash Spring (Pahranagat Valley), 2;'" Ash Meadows (Nye County), IS; Baker Creek (White Pine County), 2;'^^ Black Canyon, Colorado River, 3; Blair (Esmeralda County), 1; Candelaria, 5;''* Carson City, 1; Cedar Basin (Clark County), 2;^ Charleston Mountains, 4; Cloverdale (6 miles south of Golden, Nye County), 2; Desert Valley (23 miles west of Panaca, Lincoln County), 1;" Elko County, 8 miles south of Wendover, Utah, 1;" Esmeralda County, 2;™ Flowing Springs (Humboldt County), 2; Granite Creek (Washoe County), 7; Grapevine Mountains, 1; Groom Baldy (16 miles east, Lincoln County), 2;" Hot Creek Range (Nye County). 1;" Hot Creek Valley (Twin Spring), 1;^* Imlay, 2; Lehmain Cave (White Pine County), 1;^^ Little High Rock Canyon (Washoe County), 1;" Lund (White Pine County), 1:" Meadow Vallev (24 miles south of Caliente), 1;'' Millette, 3;"" Nyala (Nye County), 1;" Oasis Valley (Nye County), 6; Osobb Valley (Churchill County), 1; Pahranagat Mountains (Lincoln County), 1; Pahranagat Valley, 5;" Pahroc Spring (Lincoln County). 1; Pahrump Valley (Nye County), 10; Pyramid Lake, 14; Quinn ■^^Mus. Vert. Zool. ''*' J. H. Fleming collection. 's Field Mus. Nat. Hist. ''^Kansas Univ. Mus. ™ San Diego Soc. Nat. Hist. «« California Inst. Tech. 1938] REVISION OF THE GROUND SQUIRRELS 173 Canyon Mountains, 1 ;" Raspberry Creek (near Cosgrave, Pershing County), 1; Reese River (Nye County), 1; St. Thomas, 1;*" Sharp (Nye County), 4;" Silver Peak Mountains, 4; Spring Valley (White Pine County), 2;'" Thorp Mill (east base Grapevine Mountains), 2; Timpahute Mountains, 1; Virgin Valley (Humboldt County), 1;'^ Virginia Mountains, 2; Vegas Valley (Lin- coln County), 3; Wadsworth, 6; Washoe Lake, 1; White River Valley (Nye County ) , 1 ;'^ Winnemucca Lake, 10. Oregon: Adel (Lake County), 4; Rome (Malheur County), 1; South Warner Lake, 1; Tumtum Lake, 6; Vale, 1; Warner Valley, 1; Watson (Malheur County), 10. Utah: Canaan Spring (Washington County, near Arizona line), 1; Clear Creek (Sevier County), 1; Elberta (Utah County), 2;^" Esealante, 1;™^ Fillmore, 1; Hebron (Washington County), 4; Junction (Piute County), 1; Marysvale, 2; Monroe, 2;" Nephi, 1; Parowan, 1;''* Promontory Point (Box Elder County), 1; St. George, 9; Sevier River (10 miles south of Panguitch), 1; Toquerville, 2. CITELLUS LEUCURUS TERSUS (Goldman) Gband Canyon Antexope Squirrel AmmospermophUns Jeiicurus tersus Goldman, Jour. Wash. Acad. Sci. 19: 435, Nov. 19, 1929. Type. — Collected in Prospect Valley, Grand Canyon, Hiialpai In- dian Reservation, Ariz, (4,500 feet altitude) , October 3, 1913, by E, A. Goldman ; male subadult, skin and skull, no. 202645, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 22269). Range. — Terraces on southern side of Grand Canyon, in the Hual- pai Indian Reservation, Ariz. (fig. 17). Zonal Range: Upper Sonoran. External characters. — Similar in size to C. I. leucunts, but upper parts darker (more brownish, less grayish), especially on the rump and lower back. Compared with C. I. cinnamomeiis: Upper parts more brownish (less pinkish or cinnamon) ; size smaller. Cranial characters. — Skull similar to that of leucurus., but averag- ing slightly smaller in length and zygomatic breadth; nasals about same length, but slightly narrower. Color. — Winter pelage: Upper parts fawn color or army brown; shoulders and fore back heavily sprinkled with whitish hairs; hinder back, rump, and thighs darker; feet whitish, washed with light vina- ceous cinnamon; under parts creamy white; tail as in leucurus. Full summer pelage not seen ; in a worn specimen taken October 3 the head and fore back are pinkish cinnamon, the rest of the body in winter pelage. Molt. — The fall molt occurs in late September; a specimen taken September 26 has acquired winter pelage over the entire body except- ing the head ; others taken October 3 still retain worn summer pelage on the anterior half of the body, the rest being in full winter pelage. Measurements. — Average of 9 adults from type locality : Total length, 204 (19^214) ; tail vertebrae, 62 (54-72) ; hind foot, 39 (3S-40) ; ear from notch, 8 (7-9). Skull: Average of 10 adults (5 males, 5 females) ; Greatest length, 37.5 (37-39.1) ; palatilar length, 17 (16.5-17.5) ; zygomatic breadth, 21.9 (21.3- 22.6) ; cranial breadth, 18.5 (18-19) ; interorbital breadth, 9.3 (8.6-9.6) ; post- orbital constriction, 13.7 (13.3-14.3) ; length of nasals, 11.6 (11.2-12.5) ; maxil- lary tooth row, 6.7 (6.S-7.4). •'••' Mu.s. Vert. Zool. ■" Tltnh State Agr. College. « Cleveland Mus. Nat. Hist. »^ California Inst. Toch. •"» Brigham Young Univ. 174 NORTH AMERICAN FAUNA [No. 56 Remarks. — Goldman (1929, p. 435), has described the habitat of this race as follows: In the Grand Canyon of the Colorado River, which bisects the high plateau region of northern Arizona, antelope squirrels are restricted mainly to the broader terraces bordering the inner gorge. These terraces are cut at frequent intervals by side canyons, some of which extend with sheer walls to the nearly or quite precipitous outer rim of the main canyon. The higher parts of the Coconino Plateau along Grand Canyon are unsuited to the needs of antelope squirrels and the side canyons mentioned, while not absolute barriers at their heads, evidently tend to break the continuity of range within the main canyon. Specimens examined. — Total number, 10, from type locality. CITELLUS LEUCURUS CINNAMOMEUS (Merbiam) RusTT Antelope Squikrel Tamias leucurus cinnamomeus Merriam, North Amer. Fauna 3 : 52, Sept. 11, 1890. Anisonyx (Animosperniophilus) leucurus cinnamomeus Allen, Amer. Mus. Nat. Hist. Bull. 7: 240, 1895. [Spermopliilus leucurus] cinnamomeus Elliot, Field Columb. Mus. Pub., Zool. Ser. 2 : 86, 1901. Citellus leucurus cinnamomeus Elliot, Field Columb. Mus. Pub., Zool. Ser. 6: 97, 1905. AmmospermopMlus leucurus cinnamomeus Mearns, U. S. Natl. Mus. Bull. 56: 299, 1907. Type. — Collected at Echo Cliffs, Painted Desert, Ariz., September 22, 1889, by C, Hart Merriam and Vernon Bailey; female subadult, skin and skull, no. f||-|-, U. S. Natl. Mus. (Biological Survey collec- tion) (orig. no. 510). Range. — Northeastern Arizona, southern "Utah, and southwestern Colorado ; north to Mount Carmel, Utah and Coventry, Colo. ; south to Taylor, Ariz. (fig. 17). Zonal range: Mainly Upper Sonoran. External characters. — Similar to G. I. leucurtis., but coloration of upper parts darker and more reddish (less grayish) ; hind legs darker. Cranial characters. — Skull similar to that of leucurus but averag- ing slightly larger, with longer nasals. Color. — Winter pelage: General tone of upper parts vinaceous cinnamon, more or less darkened, especially on the hinder back and rump by mikado brown, which forms a subterminal band on most of the hairs ; many of the hairs are tipped with white, most strongly on the fore back; sides of head and neck washed with fuscous; eye ring buffy w^hite; lateral stripes creamy white; hind legs vinaceous cinnamon to army brown, the feet buffy white, washed with pinkish cinnamon ; front legs similar, but paler ; tail above, mixed black and white; tail beneath, creamy white, bordered with black; under parts white, washed with cartridge buff. Summer pelage: Upper parts nearly uniform vinaceous cinnamon ; feet light vinaceous cinnamon ; otherwise as in winter. Molt. — A specimen from the Grand Canyon, Ariz., taken May 27, shows new pelage appearing on the head and nape; one from the Navajo Indian Eeservation, June 14, had nearly completed the spring molt, new pelage covering all of the body except the rump and hind legs. Measurements. — ^Average of 12 adults (7 males, 5 females) from the Painted Desert and Keams Canyon : Total length, 225.8 (215-238) ; tail vertebrae, 73 (64-79) ; hind foot, 40 (39-43). STcull: Average of 8 adults (4 males, 4 females) from the Painted Desert: Greatest length, 89.3 (38.9-39.7); palatilar length. 1938] REVISION OF THE GROUND SQUIRRELS 175 17.3 (16.5-18) ; zygomatic breadth, 23 (22-23.7) ; cranial breadth, 19.1 (18.5- 19.7) ; interorbital breadth, 9.5 (9.3-9.8) ; postorbital constriction, 14.1 (13.6- 14.5) ; length of nasals, 12.4 (11.9-13) ; maxillary tooth row, 7.2 (7.1-7.8). Remarks. — This richly colored race has a much more restricted dis- tribution than leuGurus, occurring chiefly in the deserts of north- eastern Arizona. Specimens from Fredonia, in extreme northern Ar- izona, do not differ appreciably from those living on the south side of the Colorado River; at Kanab and Mount Carmel, Utah, however, the animals are paler and show evidence of intergradation with leucurus. The series from Bluff City and Noland Ranch, on the San Juan River, southeastern Utah, is typical. One specimen from Coventry, Colo., seems referable to cinnamorneus, although it appears to represent an intrusion into the range of C. I. pennipes. Specimens examhied. — Total number, 110, as follows : Arizona: Apache County (near Keams Canyon), 3; Aztec Tank (Coconino County), 5; Cedar Ranch Wash (Locket Tank, Coconino County), 2; Deadman Wash (Coconino County), 1; Fredonia, 4; Grand Canyon, 9 (Indian Gardens, 6; Pipe Creek, 2; Bass Camp, 1): Holbrook (fs^ivajo County), 9; Jacobs Pool (Coconino County), 4; Kayenta (Navajo Indian Reservation), 1; Keams Canyon (Navajo County), 11; Lees Ferry (north side), 3; Lukachukai (Navajo Indian Reservation), 2; O'Leary Peak (6,000 feet altitude), 1; Oraibi (Hopi Indian Reservation), 4; Painted Desert, 8; Taylor (Navajo County), 1; Tuba (Coconino County), 5; Winslow, 12; Zuni River (Apache County), 1. Colorado: Ashbaugh's Ranch (near McElmo, Montezuma County), 1; Cov- entry, 1. Utah : Bluff City (San Juan River) , 6 ; Kanab, 6 ; Mount Carmel (Kane County) , 3; Noland Ranch (San Juan River), 2; Notom (Wayne County), 2;^" Willow Tank Spring (Kane County), 3.*"" CITELLUS LEUCURUS PENNIPES (Howell) Colorado Antbxope Squierel Ammospermophilus leucurus pennipes Howell, Jour. Mammal. 12: 162, May 14, 1931. Type. — Collected at Grand Junction, Colo., November 11, 1895, by A. H. Howell; female adult, skin and skull, no. 75683, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 494). Range. — The Colorado Valley and its tributaries (except the San Juan) in western Colorado, eastern Utah, and northwestern New Mexico ; north to Vernal, Utah and Rangely, Colo. : west to Thurber, Utah; south to Socorro Mountains, N. Mex. (fig. 17). Zonal range: Upper Sonoran. External characters. — Similar to G. I. cinno/inomeus^ but upper parts in winter pelage more grayish (less vinaceous) and in summer pelage darker and more brownish. Compared with C . I. leucurus: upper parts in whiter pelage averaging more vinaceous (less gray- isli) in general tone; in summer pelage decidedly more vinaceous. Cranial characters. — Skull similar to that of cinnamorneus but averaging slightly larger; decidedly larger than that of leucurus. Color. — Winter pelage (November) : Upper parts light vinaceous cinnamon, the hairs on the median dorsal area from crown to rump extensively tipped with white; flanks and hind legs vinaceous cinna- wh Brlgham Young Univ. I'^Q NORTH AMERICAN FAUNA [No. 56 iiion, shading to pale pinkish buff on the hind feet; front feet sim- ilar ; lateral stripes creamy white ; tail above, mixed black and gray- ish white, shaded with the body color at the base, the hairs showing a broad subterminal band of black; tail beneath, creamy white, bor- dered with black ; under parts white, tinged with pale buff. Summer pelage (June) : Upper parts light pinkish cinnamon, more or less darkened on the median dorsal area by the fuscous bases of the hairs and shaded on the shoulders by a wash of white; flanks and hind legs light vinaceous cinnamon, shading to pinkish buff on the feet; under parts buffy white ; tail as in the winter pelage. AIoU. — A specimen from Huntington, Utah, taken in April, shows the summer pelage coming in on the head and fore back. Measurements. — Average of 10 adults (4 males, 6 females) from type locality: Total length, 226.6 (220-239) ; tail vertebrae, 68.8 (60-76) ; hind foot, 39 (38--41) ; ear from notch (dry), 8.7 (7-10). Skull: Average of 9 adults (5 males, 4 females) from type locality: Greatest length, 40.2 (38.9-41.8); palatilar length, 18.2 (17.8-18.6) ; zygomatic breadth, 23.2 (22.6-24.2) ; cranial breadth, 18.9 (18.4-19.5) ; interorbital breadth, 9.6 (9.3-10.1) ; postorbital constriction, 13.7 (13.1-14.5) ; length of nasals, 12.7 (12-13.7) ; maxillary tooth row, 7.1 (6.3-7.5). Remarks. — This race, apparently most closely related to cinna- momeus, differs from it in being less strongly vinaceous in color; in this respect it approaches leucurus but it has a decidedly larger skull. A series in full winter pelage from Fruitland and Shiprock, N. Mex., agrees closely with typical pennipes, and differs markedly from the series of cinnamomeus from Bluff City, Utah, lower down in the same valley. Specimens from Jemez, Rio Puerco, and Socorro Mountains, N. Mex., seem referable to pennipes and show no approach to G. in- terpres., which occurs on the eastern side of the Rio Grande Valley. Specimens examined. — Total number, 72, as follows : Colorado: Fruita, 1; Grand Junction, 22; Hotchkiss, 2; Rangely (Rio Blanco County), 1 ; White River (20 miles east of Rangely), 2. New Mexico: Albuquerque (35 miles west), 1; Fruitland (San Juan County), 12; Jemez (Sandoval County), 2; Rio Puerco (Valencia County), 1; Ship- rock (San Juan County), 2; Socorro Mountains (10 miles northwest), 1. Utah: Emery County (near Huntington), 1; Henry Mountains, 2; Jimction of Green and White Rivers, 1;*^ Lyman (Wayne County), 1; " Ouray (8 and 15 miles southwest), 11;" Thurber (Wayne County), 4; Uncompahgre Indian Reservation, 1 ; *^ Vernal, 4. CITELLUS LEUCURUS PENINSULAS (Allen) Western Peninsular Antelope SQiniREEii Tamias leucurus peninsulae Allen, Amer. Mus. Nat. Hist. Bull. 5 : 197, Aug. IS, 1893. Citellus leucurus peninsulae Elliot, Field Columb. Mus. Pub., Zool. Ser. 3 : 211, 1903. AmmospermopMlus leucurus peninsulae Mearns, U. S. Natl. Mus. Bull. 56: 299, 1907. Type. — Collected at San Telmo, Baja California, April 30, 1893, by A. W. Anthony; male adult, skin and skull, no. If-Jf, Amer. Mus. Nat. Hist. (orig. no. 8). ^ Carnegie Mus. 82 Utah State Agr. College. 88 Field Mus. Nat. Hist. 1938] REVISION OF THE GROUND SQUIRRELS 177 Range. — ^Western side of the Baja California Peninsula; east to the base of the San Pedro Martir Mountains ; south to San Fernando (fig. 17). Zonal range: Upper Sonoran. External characters. — Similar to G. I. leucurus^ but darker through- out ; the upper parts a deeper shade of vinaceous and with more black intermixed ; feet darker cinnamon ; tail more blackish above and more buffy beneath, the hairs having two black bands. Cranial characters. — Skull similar to that of leucurus, but averag- ing larger. Color. — Summer pelage (August 22) : Head and upper parts pink- ish cinnamon, more or less heavily mixed with black, the general tone near army brown; eye ring and lateral stripes creamy white; front legs and feet pinkish cinnamon or mikado brown; hind legs mikado brown or vinaceous cinnamon, shading to light pinkish cinnamon on the feet; tail above, cinnamon at base, the rest black, slightly tipped with grayish white; tail beneath, cartridge buff or buffy white, bor- dered with black and tipped with grayish white ; under parts car- tridge buff or buffy white. Variation. — One topotype (Aug. 21) has the nape and shoulders rather heavily sprinkled with grayish white. Some specimens have considerable black on the terminal portion of the tail, due to the presence of the band of black near the base of the hairs. Winter (?) pelage: Specimens taken August 21 to 23 have acquired a fresh pe- lage covering the posterior half of the body ; the general tone is near army brown, shading to vinaceous cinnamon on the legs and to light vinaceous cinnamon or pinkish buff on the feet. Molt. — An adult female taken August 21 at San Telmo shows a fresh pelage covering the posterior half of the back, similar in color to the summer pelage. An adult male from San Quintin, August 8, shows a fresh pelage appearing on the rump ; an adult female from the same locality, August 23, is in similar condition, the new i)elage covering nearly the posterior half of the body. Measurements. — Average of 5 adults (2 males, 3 females), from type locality: Total length, 224 (21J>-230) ; tail vertebrae, 74 (72-77) ; hind foot, 39.1 (38.5-40) ; ear from notch (dry), 8 (7-9). Skull: Average of 5 adults from type locality: Greatest length, 39.9 (38.&-41.4) ; palatilar length, 18 (17-19) ; zygomatic breadth, 23.2 (22.2-23.8) ; cranial breadth, 19 (18.7-19.3) ; interorbital breadth, 9.8 (9.6- 10) ; postorbital constriction, 14.8 (14-15.2) ; length of nasals, 12.2 (11.3-12.5) ; maxillary tooth row, 7.4 (7-7.7). Remarks. — This subspecies has a rather limited range on the west- ern side of the Baja California Peninsula. It is closely related to C. I. extimus, which occupies the southern end of the peninsula, but its range is separated from that of extimus by a desert area occupied by C. I. can'jleldae. Specimens examined. — Total number, 44, as follows : Baja California: Agua Escondido (near Hanson Laguna), 2;*' La Huerta (west base Hanson Laguna Mountains), 1; Rancho La Progresa, 2;" Rancho Viejo (15 miles east of Alamo), 2; Rosario, 10;'^*^ San Fernando, 2; San Quintin, 15; San Rafael Valley (20 miles east of Ojos Negros), 1; San Telmo, 8; Trinidad Valley, 1." ** Amer. Mus. Nat. Hist. ^ Mus. Comp. Zool. *« Los Angeles Museum. «7 Field ^fu8. Nat. Hist. 154970—38 12 I'Jg NORTH AMERICAN FAUNA [No. 5G CITELLUS LEUCURUS CANFIELDAE (Huey) MiD-PENINSULAB AnTELOPE SQUIEREL Ammospermophilus leucurus canfieldae Huey, San Diego Soc. Nat. Hist. Trans. 5 : 243, Feb. 27, 1929. Type. — Collected at Piinta Prieta, Baja California, Mexico (lat. 28°56' north; long. 114°12' west) , February 14, 1928, by Laurence M. Huey ; male adult, skin and skull, no. 6783, San Diego Soc, Nat. Hist. Range. — Desert region of central Baja California, from about lati- tude 30° southward over the Vizcaino Desert to about latitude 28° (fig, 17), Zonal range: Lower Sonoran, External characters. — Similar in color to C. I. leucurus but darker on body and limbs; under side of tail with more black, due to the presence of an additional black band on some of the hairs. Compared with G. I. peninsulae and O. I. exthnus^ the color is paler. Cranial characters. — Skull closely similar to that of leucurus., but with relatively wider interpterygoid fossa; smaller than that of peninsulae. Color. — 'Winter pelage (February) : Nose and front of face cinna- mon ; sides of head grayish white, shaded with fuscous ; hairs on up- per parts, from crown to rump, fuscous subterminally, tipped with grayish white on fore back and with light pinkish cinnamon on middle and hinder back (the general tone near cinnamon drab) ; lateral stripes clear white; flanks and hind legs, shoulders, and fore legs, vinaceous cinnamon, shading to light pinkish cinnamon on the feet; tail above, like the back for about one-third of its length, then mixed black and grayish white; tail beneath, creamy white in the center, somewhat darkened by the presence of a narrow band of black on the middle portion of some of the hairs; all the hairs having a broad subterminal band of black, tipped with white; mider parts creamy white. 'Worn summer pelage (September) : Upper parts and feet nearly uniform pinkish cinnamon or light pinkish cinnamon. Young (Sept, 9) : Similar to summer adults, but shoulders and fore back heavily sprinkled with white. Molt. — A much worn young individual taken September 16 at Cala- mahue shows new pelage covering the head; an adult from Santa Domingo, September 27, had acquired the winter pelage over the posterior half of the body. Measurements.- — Average of 5 adults (2 males, 3 females) : Total length, 220.6 (215-226) ; tail vertebrae, 70.8 (66-78) ; hind foot, 36 (35-38) ; ear from notch (dry), 8.2 (8-8.5). Skull: Average of 6 adults (3 males, 3 females) : Greatest length, 38.5 (37.5-39) ; palatilar length, 17.2 (17-17.5) ; zygomatic breadth, 22.8 (21.9-22.7) ; cranial breadth, 18.3 (18-19) ; interorbital breadth, 9.3 (8.9-10) ; postorbital constriction, 13.6 (12.9-14.3) ; length of nasals, 11.7 (11-12.6) ; max- illary tooth row, 6.9 (6.5-7.1). RemarTts. — This race, occupying a desert area in the middle of the Baja California Peninsula, is intermediate between leucurus on the north and extimus on the south, with both of which it intergrades where their ranges meet. Specimens examined. — Total number, 15, as follows : Baja California: Calamahue, 4; Campo Los Angeles, 2;^ Jaraguay (58 miles southeast of San Fernando), 2; Mesquital, 1;*^ Punta Prieta, 2;^ San An- dres, 1;*° Santo Domingo, 2; Yubay (30 miles southeast of Calamahue), 1. «8 San Diego Soc. Nat. Hist, *^Mus. Comp. Zool. 1938] REVISION OF THE GROUND SQUIRRELS 179 CITELLUS LEUCURUS EXTIMUS (Nelson and Goldman) SoLTHEKN Peninsular Antelope Squirrel Ammospermophilus leucurus evtimus Nelson and Goldman, Jour. Wash. Acad. Sci. 19: 281, July 19, 1929. Type. — Collected at Saccaton (15 miles north of Cape San Lucas), Baja California, Mexico, December 29, 1905, by E. W. Nelson and E. A. Goldman; female adult, skin and skull, no. 146587, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 18805). Range. — Southern part of the Baja California Peninsula, from Cape San Lucas north to about latitude 28° (except the Vizcaino Desert) ; ranging from sea level to about 1,000 feet altitude on the slopes of the mountains (fig. 17). Zonal range: Lower Sonoran and Tropical. External characters. — Similar to C. I. canfleJdae., but larger, and darker (more brownish), especially on the head, rump, and thighs. Similar to G. I. peninsulae in color, but slightly paler, the rump and thighs more vinaceous in tone rather than ochraceous. Vranial characters. — Skull larger than that of canfieldae and 0. I. leucurus., with relatively smaller bullae; closely similar to that of peninsulae., the bullae averaging slightly broader (less wheel shaped). Color. — Winter pelage: Top of head vinaceous cinnamon, shaded with fuscous ; sides of head grayish white, shaded with fuscous ; eye ring white; upper parts light vinaceous cinnamon, shaded with gray- ish white on shoulders and fore back and heavily mixed with fuscous on middle and hinder back; lateral stripes creamy white; hips and thighs vinaceous cinnamon; fore and hind feet light vinaceous cin- namon ; tail above, mixed black and buflfy white ; tail beneath, grayish white or cartridge buff, bordered with black and tipped with buffy white; under parts buffy white. Summer pelage (September) : Up- per parts vinaceous cinnamon, darkest on the head and rump, be- coming light vinaceous cinnamon on the shoulders and fore legs. Molt. — No specimens are available to show the progress of the spring molt; the fall molt begins in October on the hinder part of the body; a specimen from El Potrero, October 31, has acquired new pelage over the whole body excepting the head ; one from Comondu, November 7, is in the same condition, the head retaining old worn pelage. Measurements. — Average of 10 adults from southern Baja California (Co- mondti to Cape San Lucas) : Total length, 219.8 (208-237) ; tail vertebrae, 79 (70-87) ; hind foot, 37.2 (3;5-38) ; ear from notch, 8.9 (8-10). SJcull: Average of 11 adults from Saccaton and Cape San Lucas : Greatest length, 40.3 (39- 41.6) ; palatilar length, 19 (17.5-20) ; zygomatic breadth, 23 (22.5-23.8) ; cranial breadth, 18.6 (18.2-19) ; interorbital breadth, 9.9 (9.2-10.3) ; postorbital con- striction. 13.5 (12.7-14.9) ; length of nasals, 12.9 (11.5-13.7) ; maxillary tooth row, 7 (6.3-7.6). Remarks. — This race, occupying the southern end of the peninsula of Baja California, is most nearly related to peninsulae of the north- west coast region ; their ranges are separated, however, by the range of canfieldae, a smaller and paler race occupying the desert region in the middle of the peninsula. IgQ NORTH AMERICAN FAUNA [No. 56 SpeciTnens examined. — Total number, 70, as follows: Baja California: Aguaje de San Estaban, 1; Cape San Lucas, 24; Comondii, 9; El Potrero, 2; La Paz, 4; Matancita, 1; Saccaton (15 miles north of Cape San Lucas), 4; San Bruno, 1; San Ignacio, 6; San Jose (30 miles north of La Purisima), 2; San Jose del Cabo, 5; San Juanico Bay, 2;"° San Pablo, 6; Santana, 3." CITELLUS INTERPRES (Mebbiam) Texas Antelopb Sqxjirkel TamicCs interpres Merriam, North Amer. Fauna 4 : 21, Oct. 8, 1890. SpermopMlus interpres Bryant, Zoe 3 : 208, October 1892. Witellus] interpres Elliot, Field Columb. Mus. Pub., Zool. Ser. 4: 143, 1904. Ammospermophilus interpres Bailey, North Amer. Fauna 25 : 81, 1905. Ammospermophilus leucurus interpres Mearns, U. S. Natl. Mus. Bull. 56 : 301, 1907. Type. — Collected at El Paso, Tex., December 10, 1889, by Vernon Bailey; female adult, skin and skull, no. |f^^, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 762). Range. — ^Western Texas and south-central New Mexico, north to the Manzano Mountains; east to the Pecos Eiver Valley and the Castle Mountains, Tex.; west to the eastern side of the Rio Grande Valley in New Mexico; south to Jaral, Coahuila (fig. 17). Zoned range: Lower Sonoran. ^External characters. — Closely similar in winter pelage to G . leucurus leucurus.^ but differing from it in having an additional black band on the tail hairs ; coloration much paler and more grayish (less red- dish) than in G. I. cinnamomeus. Granial characters. — Skull similar to that of cinnamomeus but with superior outline flatter and brain case shallower ; nasals broader at posterior end, truncated squarely on a line with the ends of the premaxillae ; upper tooth row shorter. Golor. — Winter pelage: Upper parts light drab or drab gray (the tips of the hairs white, with a subterminal band of fuscous) ; nose and front of face washed with pinkish cinnamon; eye ring white; front and hind legs, and hips, pinkish cinnamon or light pinkish cin- namon; feet light pinkish cinnamon, shaded with buffy white 5 tail above, mixed black and white, with a patch of light pinkish cinna- mon at the proximal end ; tail beneath, creamy white, bordered with black and with a free black band on the middle portion of some of the hairs ; under parts white. Variation. — Two specimens from the Manzano Mountains, N. Mex., are slightly darker (pale fawn color) on the rump and hind legs. Molt. — A specimen taken at Boquillas, Tex., May 23, is in a badly worn pelage, and shows new hair coming in on the head and fore back. Measurements. — Average of 10 adults (8 males, 2 females) from El Paso, Tex. : Total length, 226 (220-235) ; tail vertebrae, 74.2 (68-84) ; hind foot, 37.8 (36-40); ear from notch (dry), 9.8 (8-11). Skull: Average of 14 adults (8 males, 6 females) from El Paso: Greatest length, 39.3 (37.7-^0.5); palatilar length, 17.3 (16-18.2) ; zygomatic breadth, 22.7 (21.5-23.8) ; cranial breadth, 18.9 (lS-19.6) ; interorbital breadth, 9.9 (9.4-10.5) ; postorbital constriction, 14.5 (13.8-15.3) ; length of nasals, 12.6 (11.8-13.8) ; maxillary tooth row, 6.6 (6.4^6.9), »oAmer. Mus. Nat. Hist. ^ Mus. Comp. Zool. 1938] REVISION OF THE GROUND SQUIRRELS Igl Remarks. — The range of this species seems to be restricted to the region east and north of the Rio Grande. There is no evidence of intergradation with cinnamomeus ; the latter is known from speci- mens taken in the Socorro Mountains, a few miles west of the Rio Grande, whereas inferpres is known from the eastern side of the river, at a point nearly opposite. /Specimens examined. — Total number, 62, as follows : Coahuila: Jaral, l.°^ New Mexico: Manzano Mountains (east foothills), 2; Organ Mountains, 1;*' San Andres Mountains, 11 ; Socorro (10 miles northeast), 1. Texas: Boquillas, 3; Castle Mountains (Crockett County), 1; El Paso, 32; Fort Lancaster (near Sheffield, Crockett County), 1; Franklin Mountains (10 miles north of El Paso), 6; Guadalupe Mountains (south end), 1; High Bridge, Pecos River (mouth), 1; Sierra Blanca, 1. CITELLUS INSULARIS (Nelson and Goldman) EspiKiTU Santo Antelope Squirrel Ammospermophilus leucuriis insularis Nelson and Goldman, Biol. Soc. Wash. Proc. 22 : 24, Mar. 10, 1909. Citellus leucurus insularis Elliot, Sup. Check-list Mammals North Amer., p. 28, 1917. Type. — Collected on Espiritu Santo Island, Gulf of California, Baja California, Mexico, February 7, 1906, by E. W. Nelson and E. A. Goldman ; female adult, skin and skull, no. 146783, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 19072). Range. — Espiritu Santo Island, Baja California (fig. 17). Zonal range: Tropical. External characters. — Closely similar to C. leucurus extimus in color, but larger, and slightly darker on flanks and hind legs; tail about same length. Cranial characters. — Skull similar to that of extimus but larger in all dimensions except the maxillary tooth row, in which the ante- rior premolar {pm^) is lacking entirely in about half the specimens and very rudimentary in the rest. Color. — In worn winter pelage practically as in extimus., except on the flanks and hind legs, which are light pinkish cinnamon. The fresh pelage is not represented in the series examined. Measurements. — Average of 7 adults from type locality : Total length, 229 (210-240) ; tail vertebrae, 78 (71-83) ; hind foot, 38.3 (36-40) ; ear from notch, 9.1 (8-11). Skull: Average of 5 adults from type locality: Greatest length, 41.8 (40.3^^2.4) ; palatilar length, 18.4 (18-19) ; zygomatic breadth, 24.2 (23.9-24.7) ; cranial breadth, 18.9 (18.7-19) ; interorbital breadth, 10.1 (9.8-10.6) ; postorbital constriction, 13.8 (13.4-14) ; length of nasals, 13.6 (12.3-14.3) ; maxillary tooth row, 6.5 (6.4-6.7). Remarks. — Although resembling the mainland race (extimus) very closely in color this island species has developed pronounced cranial and size characters. Specimens examined. — Total number, 14, from type locality. »2 Field Mus. Nat. Hist. »» State College, N. Mex. ]^32 NORTH AMERICAN FAUNA [No. 56 GITELLUS NBLSONI (Mereiam) San Joaquin Antelope Squirrel Spermophilus nelsoni Merriam, Biol. Soc. Wash. Proc. 8 : 129, Dec. 28, 1893. Citellus nelsoni Elliot, Field Columb. Mus. Pub., Zool. Ser. 3 : 290, 1904. Ammospermophilus nelsoni Lyon and Osgood, U. S. Natl. Mus. Bull. 62 : 172, 1909. AmmospermopMlus nelsoni a,mplus Taylor, Calif. Univ. Pubs'., Zool. 17 : 15, 1916 (20 miles south of Los Banos, Merced County, Calif.). r?/^e.— Collected at Tipton, Tulare County, Calif., June 24, 1893, by C. P. Streator • male adult, skin and skull, no. 54651, U. S. Natl. Mus. (Biological ourvey collection) (orig. no. 2968). Range. — San Joaquin Valley, Calif., from Los Banos south to Fort Tejon; west to the Carriso Plain and Cuyama Valley (fig. 17). Zonal range: Lower Sonoran. External characters. — Similar to G. leucurus leucurus but colors more buffy (less grayish) in both winter and summer pelage. Cranial characters. — Skull similar to those of leucurus and G. I. cinnamomeus.^ but larger, with heavier and more wide spreading zy- gomata and larger audital bullae, Golor. — Summer pelage; Upper parts uniform pinkish buff or pale pinkish buff; a narrow stripe of creamy white on either side of the dorsal area, from the shoulders to the rump ; fore and hind limbs light pinkish cinnamon, the feet pinkish buff; tail like the back for the basal third above^ the remainder black or fuscous black, edged with creamy white; tail beneath, creamy w^hite, with a subterminal band of blackish; under parts creamy white. Winter felage (October) : General tone of upper parts varying from wood brown to light drab, the hairs with a subterminal band of fuscous and tipped with pinkish buff or buffy white ; front legs light pinkish cinnamon next the body, shading to pinkish buff on the feet ; hind legs and thighs pinkish cin- namon or sayal brown. Molt. — The spring molt occurs in late April or early May. Speci- mens taken April 15 are still in worn winter pelage; a female from Carriso Plain, April 27, has nearly completed the molt, there being a patch of winter pelage still remaining on the head and another patch on the hinder back; another female taken at Bakersfield, May 6, shows new pelage coming in irregularly on the head, sides, and middle of the back. The fall molt occurs in September and progresses from the rump forward ; a specimen taken at Mendota, September 28, had acquired fresh winter pelage over the posterior half of the back and sides; another taken at Alila, October 8, has the fresh pelage covering all but the head and face. Measurements. — Average of 10 adult males from type locality : Total length, 231.2 (218-240) ; tail vertebrae, 70 (68-79) ; hind foot, 41.2 (40-43) ; ear from notch (dry), 8.2 (8-9). Average of 10 adult females from type locality: Total length, 229.9 (221-237) ; tail vertebrae, 67.4 (62^72) ; hind foot, 39.7 (39^1) ; ear from notch, 8.5 (8-9.5). Skull: Average of 12 adults (3 males, 9 females) from type locality: Greatest length, 41.1 (40-41.9) ; palatilar length, 18.9 (18-19) ; zygomatic breadth, 24.5 (23.5-25.7) ; cranial breadth, 19.6 (18.8-20.6) ; interorbital breadth, 10.1 (9.6-10.5) ; postorbital constriction, 13.8 (13.5-14.3) ; length of nasals, 12.4 (11.2-13) ; maxillary tooth row, 7.7 (7.2^8.5). Remarks. — This species is quite distinct from leucurus.^ and the ranges of the two do not overlap, so far as known. Its habits are bimilar to those of the other members of the subgenus Ammospermo- philus. 1938] REVISION OF THE GROUND SQUIRRELS 183 Comparison of a typical series of '■'■amplus'''' with typical nelsoni shows the differences to be too slight to warrant recognition in nomen- clature. The skulls average slightly larger — about one millimeter in iength and in zygomatic breadth. No appreciable difference in color can be detected. Specimens examined. — Total number, 210, as follows : California: Adobe Station (near Keru Lake), 1; Alcalde (Fresno County), 7; Alila (= Earlimart), 8; Bakersfield (8 miles northeast and 20 miles south), 37 ; " Buena Vista Lake, 3 ; Carriso Plain, 11 ; Coalinga, 3 ; Cuyama Valley, 10 ; Dos Falos, 2; Firebaugh (Fresno County), 1 ; ** Five Willow Springs (23 miles southeast of Simmler), 4; Huron (Fresno County), 8; Los Banos, 30;*" Lerdo (Kern County), 2; Maricopa, 4; "' McKittrick, 5; Mendota (Fresno County), 7; Panoche Creek (10^15 miles southwest of Mendota), 2;°° Panoche Pass (Fresno County), 1;"' Poso (=Famoso, Kern County), 3; Rose Station (4 miles north of Fort Tejon), 5; ^ Santa Maria Springs (7 miles southwest of McKittrick), 1 : Simmler (8 miles east, on Carriso Plain), 11; Stanley (=Turk, Fresno County), 1; Sunset (= Hazelton, Kern County), 5; Temploa Mountains, 2; Tipton (Tulare County), 36. Subgenus XEROSPERMOPHILUS Merriam [Characters on p. 45] Key to Species and Subspecies a\ Under side of tail white mohavensis (p. 1S3) a'. Under side of tail not white. &\ Upper parts drab. c\ Darker tereUcaudus{^. 185) y. Paler (light drab) clilorus (p. 188) b". Upper parts vinaceous cinnamon or cinnamon drab. c\ Paler (light vinaceous cinnamon) tercticaudus (p. 185) c\ Darker (vinaceous cinnamon or cinnamon drab). d\ Habitat Arizona and Sonora neglectus (p. 187) d^. Habitat Baja California uijricus (p- 190) CITELLUS MOHAVENSIS (Merriam) Mohave Ground Squirrel Spermopkiliis moluivcnsis Merriam, North Amer. Fauna 2:15, Oct. 30, 1889, [Citcllus]mohuvvnsis Trouessart, Cat. Mamm., Sup., p. 341, 19U4. [Citellus] tercticaudus mohavensis Elliot, Field Columb. Mus. Pub., Zool. Ser. 3: 291, 1904. Type. — Collected near Rabbit Springs, about 15 miles east of Hes- peria, San Bernardino County, Calif., June 29, 1886, by Frank Ste- phens (Grinnell and Dixon, 1918, p. 667) ; male adult, skin and skull, no. 186469, U. S. Natl. J\lus. (no. -ffH, Merriam collection) (orig. no. 315). Range. — Mohave Desert, Calif., west to Palmdale, Los Angeles County; north to Haiwee Meadows, Inyo County, south to Rabbit Springs, San Bernardino County (fig. 18). Zonal range: Lower Sonoran. External characters. — Similar in external appearance to C. town- sendii mollis but general tone of upper parts more pinkish (less gray- ish) without trace of mottling; imder side of tail clear whitish instead of cinnamon. »<]Mus. Vert. /ool. ^^ W. T. Shaw collection. »8 Field Mus. Nat. Hist. 184 NORTH AMERICAN FAUNA [No. 56 Cranial characters. — Skull similar to that of C. tereticaudus but averaging larger; slightly larger than that of O. townsendii mollis and differing from it in the characters distinguishing the subgenus Xerospermophilus ; brain case short and broad; rostrum short, the nasals ending nearly on a line with the premaxillae ; zygomata heavy, widely expanded, and twisted so that they occupy a position about midway between ver- tical and horizontal; postorbital processes broad at base, nar- rowing rapidly to slender tip, which is depressed ; incisors moderately short and stout, slightly re- curved; audital bul- lae broad and evenly rounded, consider- ably inflated. Color. — Unworn •winter pelage (March) : Upper parts uniform light drab, with a tinge of light vinaceous cin- namon, strongest on the forehead ; front feet light pinkish cinnamon; hind feet pale buff, washed with light pinkish cinnamon or pinkish buff; tail above fus- cous, overlaid with creamy white; tail beneath, clear creamy white; under parts creamy white. Summer pelage (May) : Upper parts drab or avellaneous. Molt. — A female specimen taken May 12 shows a new pelage cover- ing the head, shoulders, and most of the back. Measurements. — ^Average of 11 adults from Mohave Desert, Salt Wells Valley, and Palmdale: Total length, 222.5 (210-230) ; tail vertebrae, 65.5 (57-72) ; hind foot, 35.5 (32^38). Skull: Average of 11 adults from Mohave Desert, Salt Wells Valley, and Little Lake: Greatest length, 38.7 (38.1-40) ; zygomatic breadth, 24.3 (23.5-25.3) ; breadth of cranium, 18.2 (17.6-19.3) ; interorbital breadth, 8.7 (7.1-9.6); postorbital constriction, 12.7 (11.8-13.3); length of nasals, 12.9 (12.2-13.5) ; maxillary tooth row, 7.8 (7.6-8). Remarks. — The Mohave ground squirrel is remarkable for the lim- ited extent of its range and for the fact that it has no near relatives. It is readily distinguished from the other unspotted ground squirrels by the white under surface of the tail. Its range apparently meets but does not overlap that of tereticaudus. The latter occupies the eastern side of the Mohave Desert as far west as Daggett (Elliot's record of C. mohavensis at Daggett (1904, p. 291) is an error, all the specimens taken there being C. fereticaudics) , while mohavensis occurs on the western side, along the Mohave River. Figure 18. — Distribution of Citellus mohaven»is. 1938] REVISION OF THE GROUND SQUIRRELS 185 Specimens examined. — Total number, 23, as follows: California: Haiwee Meadow (10 miles south of Owens Lake), 1; Hesperia (San Bernardino County), 1;"' Little Lake (Inyo County), 2;** Mohave, 1; Mohave Desert, 2; "Mohave River" (=Rabbit Springs, 15 miles east of Hesperia), 6; Oro Grande (San Bernardino County), 1; Palmdale, 1; Salt Wells Valley (=north end Mohave Desert), 7; Victorville, 1." CITELLUS TERETICAUDUS (Baied) [Synonymy under subspedes] Speciftc characters. — Similar in general external appearance to C. toiunsendii mollis, but never with any traces of dappling ; tail longer and less bushy ; ears a mere rim ; hind foot, 32-40 mm ; tail, 60-102 ; skull length, 34.3-39.3. Skull closely similar to that of C. mohavensis. Upper parts vinaceous cinnamon, pinkish cinnamon, light drab, cin- namon drab, or ecru drab; tail beneath, drab or buff (never white). CITELLUS TERETICAUDUS TERETICAUDUS (Baird) ROTJND-TAILED GEOUND SQITIBREL (Pis. 27, C; 32, C) Spermophilus tereticaudiis Baird, Pacific R. R. Rept. 8:315, 1857. Citellus tereticaudus Elliot, Field Columb. Mus. Pub., Zool. Ser. 3 : 211, 1903. Citellus eremonomus Elliot, Field Columb. Mus. Pub., Zool. Ser. 3: 243, 1903. (Furnace Creek, Death Valley, Calif.) Citellus tereticaudus mohavensis Elliot, Ibid, p. 291, 1904 (not Spermophilus mohavensis Merriam). Citellus tereticaudus vociferans Huey, Biol. Soc. Wash. Proc. 39: 29, 1926 (San Felipe, Baja California). Ootypes. — Collected at Old Fort Yuma, Imperial County, Calif., by Maj. G. H. Thomas; male subadult, skin and skull, no. Hit; female immature, in alcohol, no. 2490, U. S. Natl. Mus. Range. — Deserts of southern California and northeastern Baja California; north to Death Valley, Calif., and Ash Meadows, Nev.; east to Bunkerville, Nev., and extreme northwestern Arizona; south to San Felipe Bay, Baja California; west to Kramer on the Mohave Desert (Grinnell and Dixon, 1918, p. 669) and to La Puerta, San Diego County, on the Colorado Desert (fig. 19). Zonal range: Lower Sonoran. External characters. — Similar to C. toirnsendii mollis but tail much longer; coloration more pinkish (less grayish); under parts white instead of buff. Compared with C. tnohavensis : Tail longer, less bushy, and nearly unicolor (not white beneath). Cranial characters. — Skull similar to that of mohavensis^ but aver- aging slightly smaller. Color. — Cinnamon phase (unworn winter pelage) : Upper parts light vinaceous cinnamon, the hairs with narrow whitish bands; sides of nose and face washed with dull white or pale smoke gray ; eye ring whitish; feet white or cartridge buff; basal half of tail above^ like back; terminal half shaded with fuscous and edged with whitish; tail beneath, cartridge buff; under parts white. Drah phase: Upper parts drab, some individuals shaded witli cinnamon. In summer the pelage is thinner and slightly paler. "' lios Angeles Museum. ••Mus. Vert. Zool. "E. T. Seton collection. 186 NORTH AMERICAN FAUNA [No. 56 Molt. — The spring molt occurs from the middle of March to the middle of May, varying with the locality. There is no clear evidence of a fall molt, but judging from the full, silky pelage of winter specimens, it seems probable that there is a renewal of the pelage in Measurements.- — Average of 11 adults from Fort Yuma and- Pilot Knob, Calif. : Total length, 249.5 (235-266) ; tail vertebrae, 91.1 (81-102) ; hind foot, 36.2 (33-38). Skull: Average of 16 adults from same region: Greatest length, 36.5 (34.9-38.3) ; palatilar length, 16.9 (16-18.3) ; zygomatic breadth, 23 (21.8-24) ; breadth of cranium, 17.5 (16.8-18.5) ; interorbital breadth, 8.9 (8.2-10.3) ; postorbital constriction, 12.4 (11.7-13.1) ; length of nasals, 11.7 (10.3^12.8) ; maxillary tooth row, 7.2 (6.7-7.8). Remarks. — The round-tailed ground squirrel has a wide range on the deserts of California and Baja California, and a closely related form {C. t. neglectus) occupies a large part of western Arizona and northern S o n o r a. Although closeljT- re- lated to G. mohaven- sis it is quite distinct from that species and apparently their ranges do not over- lap/ Its r e s e m- blance in color to mollis does not of course indicate close relationship. '"''Gitellus er&mono- 'mus^'' of Elliot was based on a small series from Death Valley ta,ken in late April. There is now available from this valley a series of over 30 specimens, representing all the pelage variations, and showing that there are two color phases with numer- o u s intermediate specimens. The cin- namon phase is rep- resented in both summer and winter pelage and shows no appreciable differences from typical tereticaudus from the Colorado Valley. The drab phase is likewise represented in both pelages. A consider- able series from Daggett, Calif., contains specimens representative of both color phases and some intermediates. Comparison of a series of 30 topotypes of '■''CiteTlus vociferans'^'' Huey with large series of typical tereticaudus shows that the alleged 1 Elliot's assignment (1904, p. 291) of mohavensis as a subspecies of tereticaudus is based on a misidentification of specimens from Daggett, Calif., these being typical tereticaudus. Figure 19. — Distribution of the subspecies of Citellus tere- ticaudus: 1, G. t. tereticaudus ; 2, C. t. chlorus; 3, C. t. neglectus; 4, C. t. apricus. 1938] REVISION OF THE GROUND SQUIRRELS 187 characters of '"'■'vociferans''' are covered by individual and seasonal variation in tereticmidus. Specimens examined. — Total number, 231, as follows: Baja California: Gardner's Laguna, Salton River, 1; Mexicali, 4;* San Felipe, 24 ; - " San Felipe Bay, 12. California: Amargosa Valley, 1; Bard (Imperial County), 17; =" Baregas Springs (=Borego, San Diego County), 1; Barstow, 2;*° Blythe Junction (Riverside County), 4;^ Brawley, 1; Calexico, 1; Colorado Desert (Carrizo Creek and Salt Creek), 5; Colorado River (opposite Parker, Ariz), 1; Coyote Well (Imperial County), 4;* Daggett, 34; '« Death Valley, 51;'*" Fort Yuma, 6; Indian Well, New River (San Diego County), 1; Ivanpah (San Bernardino County), 1 ; Laguna Dam (Imperial County), 4 ; La Puerta (San Diego County), 4 ; ^ * ^ Needles, 29; Pilot Knob (Imperial County), 6;' Riverside County (25 miles southwest of Ehrenburg, Ariz.), 1; Salton Lake, 6.* Nevada: Ash Meadows (Nye County), 4; Bunkerville (Clark County), 1; Las Vegas, 1;" Muddy River (Clark County), 2;' Pahrump Valley, 1; St. Thomas, 1.' CITELLUS TERETICAUDUS NEGLECTUS (Mereiam) Arizona Round-tailed Ground Squibkel SpermophiJus neglcctus Merriam, North Amer. Fauna 2 : 17, Oct. 30, 1889. Spermophilus sonorietisis Ward, Amer. Nat. 25 : 158, 1891 (Hermosillo, Sonora, Mexico ) . Anisonyx (Ictidomys) tereticaudus Allen, Amer. Mus. Nat. Hist. Bull. 7: 238, 1895. [Citellus] negJectus Trouessart, Cat. Mamm., Sup., p. 341, 1904. Citelliis tereticandtis arizonae Grinnell, Biol. Soc. Wash. Proc, 31 : 105, 1918 (Tempe, Ariz.). Type. — Collected at Dolan Spring, 12 miles northwest .of Chloride, Mohave County, Ariz., Februarv 9, 1889, by Vernon Bailey; male adult, skin and skull, no. 186470, U. S. Natl. Mus. (no. ||^, Merriam collection) (orig. no. 566). Range. — Western Arizona and western Sonora; north to Detrital Valley, Mohave County, Ariz.; east to Mountain Spring, Pima County; south to Camoa, Sonora; west to the Colorado River and Gulf of California (fig. 19). Zonal range: Lower Sonoran. External characters. — Similar to C. t. tereticaudus but darker, with shorter tail and hind foot. Cranial characters. — Skull similar to that of tereticaudus but aver- aging slightly larger, with narrower rostrum and interorbital region ; nasals longer. Color. — Winter pelage (February) : Upper parts cinnamon drab or vinaceous cinnamon, the hairs with short whitish tips; tail above, same color as back, tipped with fuscous and edged with buffy white; otherwise as in tereticaudus. Summer 'pelage: Similar to the winter pelage, but shorter, harsher, and averagmg more pinkish. Molt. — ^A specimen ( $ adult) from Fort Mohave, Ariz., March 11, is in a much worn pelage, with new hair covering the head; an adult male from Gadsden, Ariz,, April 10, shows about the same condi- tion; an adult female from Texas Hill, Ariz., April 24, has acquired a new pelage over most of the body, excepting the rump; several " San Diego Soc. Nat. Hist. ' D. R. Diclcey collection. * MuR. Vert. Zool. ■• Univ. Michigan Mus. Zool. "Field Mus. Nat. Hist. ''California Inst. Tech. 2gg NORTH AMERICAN FAUNA [No. 56 specimens from Ortiz, Sonora, taken May 12, are in badly worn pelage, with new hair appearing on the head. Measurements. — Average of 10 adults (7 males, 3 females) from Dolan Spring, Mellen, and Fort Mohave, Ariz.: Total length, 227 (204-247); tail vertebrae. 72 (60-84); hind foot, 34.4 (32-37). Average of 5 adult males from Parker, Ariz.: Total length, 233 (225-243) ; tail vertebrae, 85.8 (77-95) ; hind foot, 35.5 (34.5-37). Skull: Average of 10 adults (6 males, 4 females) from Dolan Spring, Fort Mohave, and Mellen. Ariz. : Greatest length, 37.1 (35.3-39.3) ; zygomatic breadth, 23.2 (22.2-23.8) ; breadth of cranium, 17.9 (17.3-18.3) ; interorbital breadth, 8.3 (7.8-9) ; postorbital constriction, 12.3 (12-12.7) ; length of nasals, 12.6 (11.8-13.7) ; maxillary tooth row, 7.6 (7.3-8). Weight. — Two specimens, taken by Vernon Bailey, near Tucson, weighed, respectively, 116 and 133 g. Remarks. — This ground squirrel, originally described as a distinct species, now proves to be a closely related race of tereticaudus. It has been redescribed twice, under the names Spennophilus sonoriensis and Citellus tereticaudus '•''arizonae''\ both Ward and Grinnell ap- parently having overlooked Merriam's description of neglectus in their comparisons. Large series of specimens from the type locality of '•'' sonoriensis^'' and from various points in central Arizona show no important differences from typical neglectus from northwestern Ari- zona. The Sonoran series apparently has slightly shorter nasals (average, 11.6 mm) but in the absence of any color characters, it seems best not to recognize this form by name. Specimens examined. — Total number, 292, as follows : Arizona: Adonde (Yuma County), 4; Ajo 1; Cibola (Yuma County), 2;* Colorado River, at Monument no. 204, 10; Colorado River, 5 miles north- east of Laguna, 3;° Congress Junction, 4; Continental (Pima County), 1; Coyote Mountains (Pima County), 1; Dolan Spring (Mohave County), 3; Dome (Yuma County), 2; Fort Lowell (near Tucson), 16;"" Fort Mohave, 8; Gadsden, 4; Gunsight (Pima County), 1; Hackberry (Mohave County), 1; Little Meadows (east side Black Mountains, Mohave County), 1; Maricopa (Pinal County), 1; Mellen (=Topock, Mohave County), 5;* Mineral Park (Mohave County), 1; New River (30 miles northwest of Phoenix), 1; Parker, 7; Phoenix, 10; Picachio Reservoir (17 miles south- west of Florence), 1; Quartzsite (Yuma County), 2; Quitobaquito (Pima Coimty), 4- Rillito (10 miles north, Pima County), 2;" Rillito Creek (5 miles north of Tucson), 1; Sabinos Canyon (Pima County), 3;" Santa Rita Range Reserve, 6; Santa Rita Mountains (west base), 1;® Tempe, 3;' Texas Hill (Yuma Coimty), 3; Tinajas Desert (Yuma County), 1; Tucson, 19; Vicksburg (Yuma County), 2; Well ton (Yuma County), 5; Wickenburg, 2; Yuma, 60. Sonora: Altar (20 miles north), 1;" Batamotal, 6; Camoa (Rio Mayo), 2; Cienega Well (30 miles south of Monument no. 204), 1; Costa Rica Ranch, 1; Bl Doctor, 7;" Guaymas, 2;" Hermosillo, 15; Libertad (50 miles north- east), 2;" Obregon, 1;" Ortiz, 48; Pitiquito, 1;" Querobabi, 1;" Rancho Oarrizo, 2." CITELLUS TERETICAUDUS CHLORUS ErxiOT Palm Springs Ground Squirrel Citellus cMorus Elliot, Field Columb. Mus. Pub., Zool. Ser. 3 : 242, 1903. Citellus tereticaudus chlorus Grinnell, Calif. Acad. Sci. Proc. (4) 3:347, 1913. Type. — Collected at Palm Springs, Riverside County, Calif., Febru- ary 16, 1903, by Edmund Heller; male adult, skin and skull, no. 12861, Field Museum of Natural History. ' Mus. Vert. Zool. 8 Field Mus. Nat. Hist. 1" D. R. Dickey collection. 11 Univ. Michigan Mus. Zool. 12 California Inst. Tech. lyss] REVISION OF THE GROUND SQUIRRELS 189 Range. — Northwestern arm of the Colorado Desert, specifically, the Coachella Valley from Mecca northwest to Cabazon (Grinnell and Dixon, 1918, p. 674) (fig. 19). Zonal range: Lower Sonoran. External characters. — Similar to G . t. tereticaudus but coloration more drabby (less pinkish). Cranial charaxiters. — Practically the same as in tereticaudus. Color. — Winter pelage (September 27-April) : Upper parts uni- form light drab, sometimes with a slight tinge of pinkish cinnamon ; under parts white or creamy white ; sides of nose grayish white ; front feet buffy white; hind feet white; tail above, like back on proximal half, the distal half shaded with fuscous and edged with grayish white; tail beneath, light drab. Summer pelage: Upper parts near- est to ecru drab of Ridgway ; this pelage is short and much harsher than the winter pelage, which is soft and silky. Molt. — The summer pelage is acquired usually in March or April ; a specimen from Agua Caliente, taken April 11, 1894 is in badly worn condition, and shows the new pelage covering the head and throat, an irregular patch on the rump, and smaller patches on the belly ; one from Whitewater, April 21, 1894, shows new pelage cover- ing the entire under parts and the anterior two-thirds of the upper parts. A breeding female from the same locality, June 3, 1908, is in a moderately worn drab pelage, apparently the left-over winter pelage. Other specimens taken April 3 and 10 are in complete sum- mer pelage. The tail is renewed last ; specimens taken at Mecca, April 24, show the new hair on the basal portion of the tail, while others taken at the same dates have the entire tail renewed. Winter pelage is apparently acquired in September ; a specimen from Palm Springs September 27, is in complete fresh winter pelage. Measurements. — Average of 10 adults (7 males, 3 females) from Palm Springs and Whitewater: Total length, 243.3 (232-255) ; tail vertebrae, 93.2 (84-100) ; hind foot, 36.4 (35-40). Ulcull: Average of 11 adults (8 males, 3 females) from type locality: Greatest length, 36 (35.1-37); zygomatic breadth, 22.2 21.4-23.9) ; breadth of cranium, 17.6 (17.2-18.2) ; interorbital breadth, 8.6 (8.1-9.5) ; postorbital constriction, 12.7 (12.2-13.3) ; length of nasals, 11.2 (10.7-11.7) ; maxillary tooth row, 7.3 (7.2-7.6). Remarks. — The color characters separating this race from typical tereticaudus are slight, but fairly constant. Writing of this form, Grinnell and Dixon (1918, p. 674) say: The slight features by which this subspecies is distinguishable from the Yuma Round-tailed Ground Squirrel of the Imperial Valley southeast of Salton Sea may be inferred to have arisen as a result of the action of the body of water which formerly filled the Salton Sink to sea level in cutting off or isolat- ing the animals in the northwestern arm of the Colorado Desert and thus giv- ing them a chance to develop peculiarities of their own. Specimens examined. — ^Total number, 91, as follows: California: Agua Caliente (Riverside County), 10; Andreas Canyon, San Jacinto Mountains, 1; Cabazon (Riverside County), 1; Coachella (Riverside County), 1;" Mecca (Riverside County), 18;"'' Palm Spring.s, 38;""" 18 17 18 Whitewater Station (Riverside County), 22."" "D. R. Dickey collection. "Mus. Vert. Zool. " Univ. Michigan Mus. Zool. '"Acad. Nat. Sci. Philadelphia. " Field Mus. Nat. Hist. ^^ Los Angeles Mus. 190 NORTH AMERICAN FAUNA [No. 56 CITBLLUS TERETIOAUDUS APRICUS Huey Tkinidad Valley Geound Sqtjibeel Citellus tereticaudus apricus Huey, San Diego Soc. Nat. Hist. Trans. 5 : 85, Oct. 10, 1927. Type. — Collected in Valle de la Trinidad, Baja California, Mexico (lat. 31°20' north; long. 115°40' west), by L. M. Huey, July 13, 1927 ; male adult, skin and skull, no. 6308, San Diego Soc. Nat. Hist. Range. — Known only from the type locality, Trinidad Valley, Baja California (fig. 19). Zonal range: Lower Sonoran. External characters — Similar to C. t. tereticaudus but slightly darker (more brownish). Cranial characters. — Skull similar to that of tereticaudus but averaging longer, with relatively longer nasals. Color (July specimens). — Upper parts nearly uniform cinnamon drab ; sides of nose and face washed with fuscous ; feet buffy white ; tail above, cinnamon drab at base, the distal half fuscous tipped with pale buff; tail beneath, pale pinkish buff; under parts white. Measurements. — Average of 7 adults and 3 subadults {fide Huey) : Total length, 244.4 (240-260); tail vertebrae, 90.3 (83-98); hind foot, 37 (35-39). Skull: Average of 17 adults (7 males, 10 females) : Greatest length 37.5 (36.3-38.5) ; palatilar length, 17.2 (17-18) ; zygomatic breadth, 22.9 (21.8-23.9) ; cranial breadth, 17.9 (17.3-18.5) ; interorbital breadth, 8.7 (8-9.3) ; postorbital constriction,, 13 (11.7-13.6) ; length of nasals, 12.6 (11.9-13.2) ; maxillary tooth row, 7.8 (7.2-8.2). Remarhs. — This subspecies is a slightly differentiated form living in a narrow valley at the north end of the San Pedro Martir Range, at an elevation of about 2,500 feet, on the Pacific slope (Huey, 1. c.) ; the limits of its range are not known. Specimens examined. — Total number, 28, from type locality.^^ Subgenus CALLOSPERMOPHILUS Merriam [Characters on p. 45] COLOR PATTERN In most forms of this gToup the color pattern consists of a longi- tudinal white stripe on each side of the back, bordered on each side by a black stripe ; in some races the inner black stripes are absent or much reduced in extent and the outer black stripes may also be re- duced. Most of the races, in summer pelage, have a more or less dis- tinct "mantle" covering the head and shoulders, varying in color from cinnamon buff to tawny or russet; the median dorsal area is some shade of gray, buff, cinnamon, or fawn. PELAGE AND MOLT The pelage is dense and soft, the bases of the hairs plumbeous. Apparently there is but one molt annually, occurring usually dur- ing June or the first half of July, but in some cases not until the mid- dle of August. By the following spring, the pelage often shows a considerable amount of wear and the rich colors of the head and shoulders often have faded to a much paler shade, so that specimens 19 Twentj'-six in collection San Diego Soc. Nat. Hist. 1938] REVISION OF THE GROUND SQUIRRELS 191 in this condition present a very different appearance from those in fresh pelage. No evidence of a molt in the fall has been discovered. Key to Species and Subspecies (Based on typical adults in summer pelage) o\ Median pair of dark dorsal stripes prominent. b\ Under side of tail paler (cinnamon buff or pinkish cinnamon). c\ Mantle darker and more extensive tescorum (p. 199) c^. Mantle paler and less extensive cinerascens (p. 198) b^. Under side of tail darker (tawny or russet), c^. Mantle darker (russet). (Z\ Rump darker (natal brown) trinitatis (p. 211) d^ Rump paler (army brown or fawn color). e\ Color of mantle extending to the fore back. f. Dorsal area smoke gray mitratus (p. 210) f. Dorsal area fawn color cormectens (p. 205) e^. Color of mantle not extending to the fore back — caslanurus (p. 201) (f. Mantle paler (ochraceous tawny or mikado brown). d\ Hind feet huffy. e\ Under parts huffy chrysodeirus (p. 203) e^. Under parts whitish bernardmvs (p. 209) d^. Hind feet whitish. e^. Tail paler beneath (tawny). f. Head darker (hazel) trepidus (p. 206) H Head paler (mikado brown) caryi (p. 197) e^. Tail darker beneath (russet) certus (p. 208) a'. Median pair of dark dorsal stripes absent or much reduced. 6^. Tail more than 70 mm. c^. Size larger (hind foot, 43-40 mm) ; under parts darker saturatus (p. 212) Squirrex Tamias cinerascens Merriam, North Amer. Fauna 4 : 20, Oct. 8, 1890. Tamias lateralis cinerascens Tliompson [Seton], Recreation 8: 365, May 1898. [SpermopMlus] cinerascens Elliot, Field Columb. Mus. Pub., Zool. Ser. 2: 106, 1901. Citellus cinerascens Elliot, Field Columb. Mus. Pub., Zool. Ser. 6 : 106, 1905. C [allospermophilus] cinerascens Warren, Mamm. Colorado, p. 168, 1910. Type. — Collected at Helena, Mont., August 13, 1888, by C. Hart Merriam; female adult, skin and skull, no. 186465, U. S. Natl. Mus. (fi-7T5 Merriam collection) (orig. no. 4). Range. — Outlying ranges in south-central Montana and north- western Wyoming, from Helena south to Yellowstone Park and east to the Beartooth Mountains (fig. 20). Zonal range: Canadian and Hudsonian. External characters. — Similar to C. I. castanurus.^ but general tone of upper parts more grayish (less vinaceous) ; mantle similar in color but sides of face and neck more ochraceous; tail much paler beneath (less tawny) ; hind foot longer. Compared with C. I. later- alis: Upper parts more grayish (less vinaceous) ; mantle darker (more tawny) ; median pair of black stripes always present and equaling the outer pair in width; under side of tail paler. Com- pared with C. I. tescorum: Mantle paler and less extensive; tail averaging longer, and paler beneath. Cranial characters. — Skull similar to that of lateralis in size and proportions, nasals shorter, reaching but little beyond posterior bor- der of premaxillae ; decidedly larger than the skull of castanurus or G . I. chrysodeirus. Color. — Summer pelage (topotypes, August) : Top of head, nape, and sides of neck below and behind the ears hazel, bordered next the throat with ochraceous buff or ochraceous tawny; sides of nose, cheeks, and eye ring pale pinkish buff; dorsal area smoke gray, shaded on rump and thighs with mikado brown ; lower sides pinkish buff ; under parts warm buff varying to pale pinkish buff ; feet pink- ish buff or creamy white; tail above, fuscous black, edged with cin- namon buff; tail beneath, pinkish buff or pale cinnamon buff, bor- dered on sides and tip with fuscous black, and edged with cinna- mon buff or buffy white. Winter pelage (adult female topotype, Au- gust 13) : Mantle absent; entire head, nape, back, and rump, smoke gray; dorsal stripes as usual, sides ivory yellow; tail much as in summer, but usually more mixed with blackish, and lacking the clear pinkish buff of the summer pelage. 1938] REVISION OF THE GROUND SQUIRRELS IQQ Molt. — The molt evidently occurs in late summer, as indicated by the presence of adult females in winter pelage on August 13 at Helena; a female from Pahaska Tepee, Wyo., August 3, shows new summer pelage covering the head to a line a short distance back of the ears. Measurements. — Average of 4 adults (1 male, 3 females) from Yellowstone Park and vicinity: Total length, 286 (270-297) ; tail vertebrae, 107 (95-118) ; hind foot, 43.6 (41-46) ; ear from notch (dry), 14.9 (14-10). Skull: One adult male from Helena, Mont.: Greatest length, 45.6; palatilar length, 21; zygomatic breadth, 28.2 ; cranial breadth, 20.4 ; interorbital breadth, 11 ; postorbital con- striction, 12.7 ; length of nasals, 15.6 ; maxillary tooth row, 8.2. Average of 4 adult females from Helena and Emigrant Gulch, Mont., and Yellowstone Park, Wyo.: Greatest length, 43.9 (42.0^5) ; palatilar length, 20.1 (19.3-21) ; zygo- matic breadth, 27.5 (26.3-29.3) ; cranial breadth, 20.1 (19.3-20.8) ; interorbital breadth, 105 (10.2-11) ; postorbital constriction, 13.3 (12.9-13.7) ; length of nasals, 14.9 (14.5-15.5); maxillary tooth row, 8.9 (8.7-9.2). Reinarhs. — This race is most nearly related to tescorum^ but differs from it in the paler color of the mantle and in the slightly longer tail, which is clearer yellow beneath. The series available from the type locality is inadec{uate to show the range of variation in summer pelage and the exact limits of range of the subspecies are still to be worked out after more thorough collecting in Montana. Specimens examined. — Total number 28, as follows : Montana: Beartooth Mountains, 2; Butte (12 miles east), 0; Deer Lodge County, 3;^" Emigrant Gulch (near Emigrant Peak, Park County), 1; Helena, 8. Wyoming: Pahaska Tepee (Whirlwind Peak), 3; I'ellowstone Park, 5. CITELLUS LATERALIS TESCORUM (Hollisteb) HoLLISTEIl'S IMANTLED GkOUND SQTJIRREa:. Citellus iCallospennophilus) ciucrascens Preble, North Amer. Fauna 27: 166, 1908 (not of IMerriam). Callospennophilus lateralis tescorum Hollister, Smithsn. Misc. Collect. 50 (26) : 2, Dec. 5, 1911. C Hell us lateralis tescorum Elliot, Check-list Mamm. North Amer. Sup., p. 29, 1917. Type. — Collected at head of Moose Pass Branch of the Smoky River, All)erta (near Moose Pass, British Columbia), at 7,000 feet altitude, August 2, 1911, by N, Hollister; male adult, skin and skull, no. 1741G5, U. S. Natl. Mus.; original number, 3863. Range. — Northern Rocky Mountain region in western Alberta, eastern British Columbia, nortliern and central Idaho, and western Montana; north to Mount Selwyn, British Columbia; south to Edna and Ketclium, Idaho; west to the Columbia River Valley, southeast- ern British Columbia (fig. 20). Zonal range: Canadian and Hud- soiiian. Extei'nal characters. — Similar to G. I. cinerascens^ but mantle darker and more extensive, reaching over the shoulders and in some specimens nearly to the middle of the back ; under side of tail averag- ing darker. Cranial characters. — Skull closely similar to that of cinerascens; much larger than that of 0. I. castaiiurus. "" Kansas Univ. Mus. 200 NORTH AMERICAN FAUNA [No. 56 Color. — Head, neck, and shoulders russet, varying to mars brown; median dorsal area smoke gray, shaded on the rump with dull mars brown or Vandyke brown, this color nearly solid on the thighs; eye ring creamy white; light dorsal stripes creamy white, shaded with pale pinkish buff ; inner pair of black stripes nearly as wide as outer pair, but not reaching quite so far back ; sides pinkish buff or warm buff ; under parts pinkish buff ; front feet pinkish buff ; hind feet pale pinkish buff or buffy white; tail above, black, bordered with cin- namon buff; tail beneath, cinnamon buff or pinkish cinnamon, with a subterminal band of black. Winter pelage (Ptarmigan Lake, Alberta, July 9, and St. Mary Lake, Mont., June 5) : Head, neck, and median dorsal area smoke gray ; ears russet, edged with pinkish buff ; sides, under parts, and feet pale pinkish buff; under side of tail pink- ish buff or cinnamon buff. Variation. — While the topotype series is quite uniform in the color of the under surface of the tail, the series from northwestern Mon- tana shows more variation, some specimens having a paler tail (about as in cinerascens) and others a slightly darker tail, with some admix- ture of black. Molt. — A male specimen from Canadian National Park, Alberta, July 5, shows fresh summer pelage on the shoulders and crown ; two female specimens from Teton County, Mont., June 14 and 19, show new pelage in irregular patches on the head and shoulders; a breed- ing female from Thompson Falls, Mont., July 27, shows fresh pelage covering the head and ears, the rest of the pelage being in worn con- dition. A breeding female from Canadian National Park, Alberta, July 12, shows fresh summer pelage covering the head and part of the shoulders ; another fem.ale from Rocky River, Alberta, August 12, had just begun to molt, the new summer pelage covering only the head and face. Measurements. — Average of 16 adults from near type locality: Total length, 292.5 (264-308) ; tail vertebrae, 103.5 (94-112) ; hind foot, 43.1 (40-46) ; ear from notch, 13.5 (12-15). Skull: Average of 10 adult males from near type locality: Greatest length, 44.1 (42.1-46.6); palatilar length, 20.6 (20-21.5); zygomatic breadth, 27.4 (26.2-28.9) ; cranial breadth, 19.9 (19.2-20.4) ; interor- bital breadth, 10.7 (9.9-12) ; postorbital constriction, 13.2 (12.5-14) ; length of nasals, 15.5 (14.7-16.1) ; maxillary tooth row, 8.6 (8-9.1). Average of 7 adult females: Greatest length, 43.3 (42.3-44.6); palatilar length, 20.2 (20- 20.5) ; zygomatic breadth, 26.9 (26.1-27.3) ; cranial breadth, 19.4 (19-19.6) ; interorbital breadth, 10.4 (10-10.7) ; postorbital constriction, 12.7 (12.3-13) ; length of nasals, 14.9 (14.3-15.9) ; maxillary tooth row, 8.4 (8.1-8.7). Weight. — ^A female from Lost River Mountains, Idaho, weighed 12 ounces. Remarks. — This wide-ranging form was for a long time confused with cinerascens until separated by Hollister in 1911. It is one of the largest and most richly colored of all the races. It undoubtedly intergrades vv^ith cinerascens, but there is no material available to prove such intergradation. It is not strongly differentiated from cinerascens., but may be distinguished by its darker and more exten- sive mantle in summer pelage, and by its darker tail. Specimens examined. — Total number, 279, as follows : Alberta: Banff, 5;''''' Burmis, 3;'' Canadian National Park, 5;'' Canmore, 3; Grand Cache River (60-70 miles north of Jasper House), 4; Hay River (near head), 1; Henry House (15 miles south), 9; Jasper House, 2; »>Nat. Mus. Canada. '^Amer. Mus. Nat. Hist. 1938] REVISION OF THE GROUND SQUIRRELS 201 Jasper Park, 17 ; ^ Moose Mountain, 3 ; ^ Moose Pass, 2 ; Mountain Park, 2 ; '^ Pobokton River, 1 ; Ptarmigan Lake, 2 ; ^ Laggan, 2 ; Rocky River (east branch), 3;^' Smoky River (head), 9; Southesk River, 2;^ Sulphur River, 2 ; Waterton Lake Park, 11.'^ British Coliimbia : Barkerville, 11 ; Glacier, 1 ; ^ Golden City, 1 ; " Green Moun- tain (near Rossland), 1 ;'^ Indian Point Lake, S ;*' Indian Point Moun- tain, 2;^ Jarvis Pass, 1; Jubilee Creek (head, near Barkersville), 1 ; ^^ Moose Pass, 6; Moose River, 4; Mount Old Glory (near Rossland), 5;*^ Mount Selwyn, 8; Parsnip River (head), 3; Rossland, 1;^ Sukunka River, 5; Trail, 2;^ Wapiti River (head), 1; Yahk, 4;^ Yellowhead Lake, 1; Yellowhead Pass, 1. Idaho: Birch Creek (mountains west), 6; Bitterroot Mountains, 1;^^ Edna, 11; Elk Summit (Valley County), 2; Goldburg (10 miles west), 2; Ketchum, 6 ; Lakeview, 2 ; "" Lost River IMountains, 28 ; Mullan, 16 ; Patterson, 1 : Red- fish Lake, 2; "Salmon River Mountains" (=Lemhi Mountains), 7; Summit (at Trail Creek, Blaine County), 2; Warren, 1; Wood River (head, Blaine County), 2. Montana: Bass Creek (near Stevensville), 1; Bear Creek (Great Northern R. R., Flathead County), 1; Florence, 4:^^ "Horse Plains" (=Plains), 10; Lake Como (Ravalli County), 1; Lolo Hot Springs, 1; Nyack (Flathead County), 2; Prospect Creek (near Thompson Falls), 3; St. Mary Lake, 3; Summit (Great Northern R. R., Flathead County), 1; Thompson Falls, 11; Thompson Pass, 2. CITELLUS LATERALIS CASTANURUS (Mekriam) Wasatoh Mantled Ground Squirrel Manilas castanunis Merriam, North Amer. Fauna 4 : 19, Oct. 8, 1890. [SpcnuopJiilns] castanurtis Elliot, Field Columb. Mus. Pub., Zool. Ser. 2: 84, 1901. Citellus castanurus Elliot, Field Columb. Mus. Pub., Zool. Ser. 6: 106, 1905. Callospermophilus castanurus Lyon and Osgood, U. S. Natl. Mus. Bull. 62: 173, 1909. Type. — Collected at Park City, Wasatch Mountains, Summit County, Utah, July 3, 1890, by Vernon Bailey ; female adult, skin and skull, no. |-|tM) U. S. Natl. Mus. (Biological SurA^ey collection) (orig. no. 1383), Range. — Mountains of extreme westei'n W^yoming, southeastern Idaho, and north-central Utah; north to the Teton Range, Wyo. ; east to the Gros Ventre and Salt River Ranges, Wyo.; south in the Wasatch Range to Wasatch County, Utah (and probably farther); west to mountains east of Inkom, Idaho (fig. 20). Zonal range: Canadian and Hudsonian. External character,^. — Compared with C. I. lateralis: Head and mantle darker; black dorsal stripes nuich more prominent, the inner pair ahvays present and e(|ual in breadth to outer pair; under side of tail darker (more tawny). Compared witli C. I. cinera^scc/u: General tone of upper parts more vinaceous (less grayish) ; sides of face and neck less ochraceous; tail nmch darker. Similar to C. I. connectens and 0. I. trepidus, but sides of face and neck darker (more broAvn- ish) ; tail darker beneath. Cranial characters. — Skull similar to that of trepidus but averag- ing slightly smaller, and relatively narrower across z3'gomata; de- cidedly smaller than that of cinerascens or of lateralis. 31 Nat. Mus. Canada. ^ Am<.T. Mus. Nat. Hist. "Mus. Vort. Zool. ** Piovincial Mus., Victoria, Biitish Columbia. '^ Montana Stale College. ^^ Carnegie Mus. 202 NORTH AMERICAN FAUNA [No. 56 Color. — Fresh summer pelage : Head, nape, ears, shoulders, and sides of neck mikado brown, shaded with cinnamon and bordered on the throat with cinnamon buff; median dorsal area and rump fawn color, sprinkled with grayish white ; light dorsal stripes pinkish buff ; sides light ochraceous buff ; fore feet and legs pinkish buff or cinna- mon buff; hind legs and thighs mikado brown, the feet pale pinkish buff; tail above, black, bordered with cinnamon buff; tail beneath, russet, the hairs edged with cinnamon buff and with a subterminal band of black ; under parts pinkish buff or buffy white. Molt. — An adult female from Park City, Utah, July 4, was ac- quiring fresh pelage on the head, shoulders, and middle of the back ; another from the Salt River Mountains, V/yo., August 21, was still carrying old, moderately worn pelage over most of the body except- ing the head, w^here new pelage is appearing. Measurements. — Average of 8 adult males from type locality : Total length, 272 (25&-293) ; tail vertebrae, 97.1 (85-110) ; hind foot, 41.5 (39-44). Average of 10 adult females from type locality: 271 (256-280); 95.7 (91-101); 40.4 (38.5-42) ; ear from notch (dry), 15 (14-17). Sk^iU: Average of 10 adult males from type locality: Greatest length, 42.3 (40.2-44.2); palatilar length, 19.8 (19-21) ; zygomatic breadth, 26.3 (25.4-27.3) ; cranial breadth, 39.4 (18.8-20.1) ; interorbital breadth, 9.7 (8.9-10.2) ; postorbital constriction, 12.5 (11.8-13.1) ; length of nasals, 14.6 (13.5-16) ; maxillary tooth row, 8.1 (7.3-8.7). Average of 10 adult females from type locality : Greatest length, 41.9 (40.4-42.8) ; palatilar length, 19.5 (18.5-20) ; zygomatic breadth, 25.8 (25.4-26.8) ; cranial breadth, 19.1 (18.5-19.8) ; interorbital breadth, 9.8 (9-10.9) ; postorbital constriction, 12.7 (12.1-13.7) ; length of nasals, 14.5 (13.6-15.3) ; maxillary tooth row, 7.9 (7.1-8.4). Remarks. — This race clearly belongs in the chrysodeirus group, intergrading with subspecies trejndus in southern Idaho. A series of 11 specimens from Rabbit Creek, 8 miles northeast of Inkom, are paler than typical castanurus., although their tails are about as dark; one specimen from the Bannock Range, west of Swan Lake, has a paler tail and is best referred to trepidus. G. I. castanurus is widely different from lateralis and although their ranges nearly meet in northern Utah, no evidence of intergradation has been found. It iiitergrades, however, with C. I. caryi in the Gros Ventre Range and probably with cinet'ascens at the northern end of the Teton Range, Wyo. An immature specimen from Moose Creek, in that range, differs from typical castanurus in having the under side of the tail a paler shade of red, perhaps indicating an approach to cinerascens. Nine specimens from near the head of Twin Creek, in the Gros Ventre Range, Wyo., taken by Arthur B. Fuller and W. P. Bole, Jr., of the Cleveland Museum, are typical castanurus.^ whereas a single speci- men taken by H. E. Anthony, 12 miles northwest of Kendall — and thus in practically the same region — shows approach to caryi in its paler tail. Specimens examined. — Total number, 112, as follows : Idaho: Big Hole Mountains, 1; Crow Creek (Preuss Mountains), 2; Inkom (8 miles northeast), 11. Utah: Barclay (Salt Lake County), 11; Blacksmiths Fork (Cache County), 2; Bear Lake (east side), 4; Logan Canyon (Cache County), 3;" Park City (Summit County), 47; Sardine Canyon (Cache County), 1." Wyoming: Cokeville, 1; Flat Creek (at head, Teton County), 1; Gros Ventre Mountains (head of Twin Creek), 10;^^ Jackson, 5; Kendall (12 miles " Utah state Agr. College. « Cleveland Mus. Nat. Hist. 1938] REVISION OF THE GROUND SQUIRRELS 203 northwest, Sublette County), 1; La Barge Creek (9,000 feet altitude), 2; Merna (Sublette County), 1; Salt River Mountains, 4; Smiths Fork (head, Lincoln County), 3; Stanley (=MidclIe Finey Lake), 1; Teton Mountains (south of Moose Creek), 1. CITELLUS LATERALIS CHRYSODEIRUS (Mekriam) Golden-mantled Gkound Squirrel (PL 11) Tamias chrysodcirus Merriam, North Amer. Fauna 4 : 10, Oct. 8, 1890. Callospermophilus chrysodcirus Merriam, North Amer. Fauna 16 : 90, 1899. iSpermophilus'\ chrysodcirus Elliot, Field Columb. Mus, Pub., Zool. Sor. 2: 84, 1901. CitcUits chrysodcirus Elliot, Field Columb. Mus. Pub., Zool. Ser. 3 : 288, 19(^)4. Type. — Collected at Fort Klamath, Oreg., July 31, 1888, by Samuel Parker; male adult, skin and skull, no. 186164, U. S. Natl. Mus. (no. ff4t> Merriam collection) (orig. no. 143). Range. — Interior Oregon and eastern California north to the Co- lumbia River; east to the foothills of the Blue Mountains; south (in the Sierra Nevada) to Tulare County, Calif.; west to and including the Cascades in Oregon, and Mount Shasta, Calif, (fig. 20). Zonal range: Transition, Canadian, and Hudsonian. External characters. — Compared with C. saturatus and C. I. later- alis: Head darker; mantle more extensive and brighter colored; black dorsal stripes broader and more extensive, the inner pair equal in width to outer pair; under side of tail darker (more tawny). Compared with C. I. castanurus: Mantle lighter (more yellowish); light dorsal stripes clearer white; under side of tail paler; external measurements averaging smaller. Cranial characters. — Skull similar to that of lateralis, but smaller, with relatively shorter rostrum and nasals; postorbital constriction relatively greater. Compared with saturatus: Much smaller, but post- orbital constriction relatively greater. Color. — Summer pelage: Top of head mikado brown; sides of head and neck, ears, and shoulders briglit ochraceous tawny; sides of nose and lower cheeks warm buff; median dorsal area vinaceous buff or tilleul IjufF, shading to fawn color or army brown on the rump; light dorsal stripes creamy white or sometimes ochraceous buff; inner pair of black strii)es equal in length and breadth to outer pair; lower sides and feet pinkish buff; tail above, black, sprinkled with pinkish buff or ochraceous buff; tail beneath, tawny or ochraceous tawny bordered with black and edged with pinkish buff or ochraceous buff; under parts pinkish l)uff or buffy white. Winter pelage (October-April) : General tone of upper parts more grayish; mantle poorly defined; head fawn color or mikado brown; sides of head and neck cinnamon buff; median dorsal area liglit drab, shading to fawn color on the rump; under side of tail clay color; feet buffy wdiite. Molt. — An adult male from Beech Creek, Oreg., July 2, had nearly (■om])leted the molt, new |)elage covering most of the body except the hinder back and hind legs, which are in old, worn pelage. An adult female from Diamond Lake, Oreg., August 12, and another from Mount Shasta, Calif., August 21, had just begun to acquire new pelage on the head and the middle of the back. 204 NORTH AMERICAN FAUNA [No. 56 Measurements. — Average of 10 adult males from Fort Klamath and Crater Lake, Oreg. : Total length, 259 (242-275) ; tail vertebrae, 89.6 (83-94) ; hind foot. 39.7 (39^1) ; ear from notch (dry), 15.2 (14-16). Average of 10 adult females from same localities: 253.5 (235-278); 88.1 (82-102) ; 39.1 (37^1) ; 15.2 (14- 16.5). Skull: Average of 10 adult males from same localities: Greatest length, 42.3 (41^4) ; palatilar length, 19.5 (18.5-21) ; zygomatic breadth, 26.3 (24.8-28) ; cranial breadth, 19.5 (19.1-20) ; interorbital breadth, 10.2 (9.3-11.2) ; postorbital constriction, 13.2 (12.5-13.9) ; length of nasals, 14.4 (13.3-15.8) ; maxiUary tooth row, 8.2 (7.6-8.6). Average of 10 adult females from same localities: Greatest length, 41.1 (39.6-42.7) ; palatilar length, 18.7 (18-19.5) ; zygomatic breadth, 25.5 (23.8-26.4) ; cranial breadth, 19.3 (18.1-19.9) ; interorbital breadth, 9.5 (9.1-10) ; postorbital constriction, 12.7 (11.2-14) ; length of nasals, 14.4 (13.2-15.4) ; max- illary tooth row, 8 (7.4-8.7). Weight.— Average of 10 males, 181 g (155-218) ; of 10 females, 199 g (136-245) (Grinnell and Dixon, 1918, p. 676). Remarhs. — Over its very wide range, this subspecies intergrades with several other races. Specimens from Four Mile Lake, Oreg., a short distance southwest of Fort Klamath, have darker and more ex- tensive mantles than typical specimens ; in Siskiyou and Trinity Coun- ties, Calif., intergradation with the subspecies G. I. niitratus takes place, the large series from there being referred to the latter form. At the southern end of the Sierra Nevada (Sequoia National Park, Mount Wliitney, etc.) the animals differ from typical chin/so- deirus in having slightly darker mantles, thus approaching G. I. her- nardinus in color; their skulls are also closely similar to those of 'bernardinus^ being longer and relatively narrower than typical chrysodeirus ; the tails, however, are fully as long as in chrysodeh-^s. Some individuals from Mount Whitney, Bishop Creek, and head of San Joaquin River have whitish feet and bellies, thus showing ap- proach to G . I. trepidns. Several specimens from East Fork of Kaweali River have very dark tails, darker even than those of G. I. certus. jSpeci7ne7is examined. — Total number, 543, as follows : California: Alta Peak (Kaweah River, Sequoia National Park), 4; Aspen Meadow (Tuolumne County), 7; Bald Moiuitain (8 miles west, Shasta County), 1; Bartle (McCloud River), 5; Bieber (Lassen County), 1; Big Valley Mountains, 11; Bishop Creek (9,000-10,000 feet altitude, Inyo County), 4; Bear Creek Valley (west of Dana, Shasta County), 1; Beswick (Siskiyou County), 1; Bullfrog Lake (Fresno County), 6;^^ Buck's Ranch (Plumas County), 1; Bunch Grass Spring (Madeline Plains), 2; Carberry Ranch (12 miles west of Burney, Shasta County), 6; Chaparral, 3;^ Cisco (Placer County), 1; Cottonwood Lakes (Inyo County), 1;^ Crown Valley (Middle Fork, Kings River, Fresno County), 1 ; *" Cutts Meadow (near Hunt- ington Lake, Fresno County ) , 2 : ^'' Dinkey Creek ( North Fork, Kings River, Fresno County), 1 ; Donner, 20; Eagle Lake, 1 ; Eureka Mill (Shasta County), 1 ; Evolution Lake (head South Fork, San .Joaquin River), 1 ; *" Foster Ridge (near Huntington Lake, Fresno County), 1;*° Goose Lake, 2; Goose Nest Mountain (Siskiyou County), 6; Greenville (8 miles northwest), 13; Hay- den Llill (Lassen County), 3; Horse Corral Meadows (north of Mount Silli- man, Fresno Coimty), 4; Hope Valley (Alpine County), 1; Huntington Lake (Fresno County), 1;" Ice Caves (6 miles southwest of Tule Lake), 2; Kaweah River (East Fork, Sequoia National Park), 7; Kearsarge Pass (Fresno County, 5;'* Lassen County, 6; Lassen Creek (east side of Goose Lake), 7; Lassen Peak, 15; Letter Box (Plumas County), 2; Little Onion Valley, 1;^° Little Pete Meadow (Kings River, Fresno County), 1;** Long Valley (Mono Comity), 1;^° Madeline Divide, 1; Madeline Plains, 1; Marie Lake (Selden Pass, Fresno County), 1;^° Markleeville (Alpine County), 2; s^Miis. Vert. Zool. ^"Cleveland Mus. Nat. Hist. *i Wm. T. Shaw collection. « Field Mus. Nat. Hist. 1938] REVISION OF THE GIIOUND SQUIRRELS 205 McCloud (Siskiyou County), 2; McClure Meadow (head South Fork, San Joaquin River), 1;*" McKinneys (Lake Tahoe), 2; Merced River (near head), 1; Merced River (Fish Camp, on South Fork), 1; Mohawk (Pluiuas County), 1; Mono Lake, 5;^" Mono Pass, 1; Mount Dana, 1; Mount Shasta, 55 ; Mount Tallac, 5 ; Mount Unicorn, 1 ; Mount Whitney, 27 ; Mulkey Mead- ows (15 miles south of Mount Whitney), 5; Onion Valley (Inyo County), 4;^* Owens River (head), 2; Petes Valley (Lassen County), 1; Picard (Siskiyou County), 1 ; Quincy, 1 ; San Joaquin River (near head), 1 ; Sequoia National Park, 4; Shingletown (Shasta County), 1; Sierra Valley (Plumas County), 1; Sisson (Siskiyou County), 1; Summit Meadow (Tulare County), 1; Susan River (Lassen County), 1; Susanville (12 miles west), 2; Tahoe (Placer County), 1; Tenaya Lake, 1; Tuolumne Meadows, 3; Whit- ney Meadows (10 miles south of Mount Whitney), 1. Nevada: Glenbrook (Lake Tahoe), 6; Lake Tahoe, 2. Oregon: Antelope (Wasco County), 2; Arnold Ice Cave (Deschutes County), 1; Austin (Grant County), 1; Beech Creek (Grant County), 1; Bend, 7; Chiloquin (Klamath County), 1; Crater Lake, 28; Crooked River (20 miles southeast of Prineville), 1; Diamond Lake (Douglas County), 5; Drew Creek Valley (Lake County), 2; Fort Klamath, 74; Four-mile Lake (Klam- ath County), 12; Francisville (Wheeler County), 1 ; Fremont (Lake County), 4; Friend (Wasco County), 2; Gateway (Jefferson County), 2; Goose Lake Mountains, 1; Hay Creek (12 miles east, Jefferson County), 2; Heppner, 1; Howard (Crook County), 3; John Day River (Crown Rock), 3; Kamela (Union County), 1; Lone Rock (Gilliam County), 10; Maupiu (Wasco County), 2; McKenzie Bridge, 1; Meacham (Umatilla County), 1; Mill Creek (20 miles west of Warmsprings), G; Miller (mouth of Deschutes River), 6; Mount Hood, 7; Mount Mazama (Anna Creek, Crater Lake Na- tional Forest), 4; Naylox (Klamath Lake), 3; Ochoco National Forest (Crook County), 2 ; O'Leary Mountain (10 miles south of McKenzie Bridge), 1; Paulina Lake, 4; Rock Creek (Baker County), 1; Silver Lake (10 miles southwest), 2; Sisters (Deschutes County), 4; Strawl)erry Mountains, 10; Three Sisters, 5; AVapinitia (Wasco County), 9; Warm Springs River (mountains north), 1; Willows (Gilliam County), 1. CITELLUS LATERALIS CONNECTENS (Howei.l) Blue Mountains Mantled Gkound Squibkei^ CallospermophiJuii chrysodeirus conncctcns Howell, Jour. Mammal. 12 : 1(51, May 14, 1931. Type. — Collected at Hoinestead, Oro^^., June 1, 1916, by H. H. Sheldon; male adult, skin and skull, no. 212461, U. S. Natl. Mus. (Biological Survey collection^ (orig. no. 535). Range. — The Blue Mountains region of nortlieastern Oregon and southeastern Washington (fig. 20). Zonal range: Transition and Canadian. External characters. — Similar in sunnner pelage to C. I. chryso- deirus^ but head and mantle darker; shoulders and fore back more vinaceous (less ochraceous) ; under side of tail paler. Similar in color to C. I. castanurus but under side of tail paler; sides of face and neck paler (more ochraceous). Cranial characters. — Skull closely similar to that of chrysodeirus^ averaging slightly larger. Color. — Summer pelage (June 1) : Head, ears, shoulders, and sides of neck russet, shaded on sides of neck and around ears with ochra- ceous buff and ochraceous tawny, and bordered next the throat with cinnamon buff ; nape and foreback, between shoulders, cacao brown ; median dorsal area fawn color, shading to army brow^n on rump and thighs; sides of body and feet pinkish buff; light dorsal stripes aoMuH. Vert. Zoo). "Clevelaud Mus. Nat. Hist. 206 NORTH AMERICAN FAUNA [No. 56 creamy white, tinged with pinkish buff; tail above, black, bordered with cinnamon buff; tail beneath, cinnamon or tawny, edged with cinnamon buff, and with a subterminal band of black; under parts pale pinkish buff or buffy white. Winter pelage (May 8) : Mantle not well defined ; top of head pinkish cinnamon ; median dorsal area cinnamon drab, shading to fawn color on rump and to army brown on thighs ; light dorsal stripes clear white, reaching to the ears ; sides of neck washed with cinnamon buff ; sides of body pale pinkish buff. Molt. — An adult female from Homestead, Oreg., June 9, and an- other from Paradise, Oreg., June 10, were acquiring fresh pelage on the head and shoulders, the pelage on the rest of the body being con- siderably worn and faded. Measurements. — Average of 7 adult males from type region : Total length, 266 (257-280) ; tail vertebrae, 92 (80-98) ; hind foot, 41.7 (40-43) ; ear from notch (dry), 14.8 (14-16). Average of 9 adult females from type region: Total length, 266 (255-280) ; tail vertebrae, 91.5 (80-100) ; hind foot, 40.9 (40-43) ; ear from notch (dry), 14.1 (13.5-15). Skull: Average of 9 adult males from type region; Greatest length, 42.7 (41.5-44.6) ; palatilar length, 19.7 (19-20.5) ; zygomatic breadth, 26.5 (25.8-27.5) ; cranial breadth, 19.4 (18.5-20.3) ; interor- bital breadth, 9.6 (9-10.4) ; postorbital constriction, 12.3 (11-12.8) ; length of nasals, 14.9 (14-15.6) ; maxillary tooth row, 8.2 (7.2-8.8). Average of 8 adult females from type region: Greatest length, 42.4 (41.6-43.1) ; palatilar length, 19.5 (19-20.5) ; zygomatic breadth, 26.1 (24.6-27) ; cranial breadth, 19.3 (18.8- 19.9) ; interorbital breadth, 9.4 (8.9-9.7) ; postorbital constriction, 12.6 (11.6- 13.4) ; length of nasals, 14.5 (13.9-15.3) ; maxillary tooth row, 8.5 (7.9-8.9). Bemarks. — This subspecies is most nearly related to chrysodeirus, with which it intergrades in the foothill region of the Blue Moun- tains. It is very distinct from C. I. tescorum of central Idaho, and their ranges apparently do not meet. Specimens examined. — Total number, 40, as follows : Oregon: Anthony (Baker County), 1 ; *^ Cornucopia (Baker County), 6 ; *^ Home- stead (Baker County), 7; Joseph, 1;*' Paradise (15 miles northeast, Wal- lowa County), 1; Troy (Wallowa County), 4; Wallowa, 1; Wallowa Can- yon, 2 ; Wallowa Lake, 3. Washington: Anatone (Asotin County), 2; Dayton, 2;^° Godman Springs (Co- lumbia County), 6;^^ Grand Ronde River (6 miles south of Anatone), 2; Humpeg Falls (Columbia County), 2.*^^* CITELLUS LATERALIS TREPIDUS (Taylor) Nevada Mantled Ground Squirrel Callospermopliihis trepidus Taylor, Calif. Univ. Pubs., Zool. 5: 283, Feb. 12, 1910. Citellus trepidus Elliot, Check-list Mamm. North Amer. Sup., p. 29, 1917. Callospermophilus clrrysodeirus perpallklus Grinnell, Calif. Univ. Pubs., Zool. 17: 429, 1918 (White Mountains, Calif.). Type. — Collected at head of Big Creek, Pine Forest Mountains, Humboldt County, Nev. (8,000 feet altitude), June 27, 1909, by W. P. Taylor and C. H. Richardson, Jr.; male adult, skin and skull, no. 8240, Mils. Vert. Zool. (orig. no. 768). Range. — Southeastern Oregon, southern Idaho, northern and cen- tral Nevada, and northwestern Utah; north in the Snake River Val- ley to southern Baker County, Oreg. (Home P. O.) ; west to Mount Warner, Oreg., and the Granite Range, Nev.; south to the Toyabe Mountains, Nev. and the AVhite and Inyo Mountains, Calif.; east to Bannock County, Idaho (Swan Lake) and the Snake Range, eastern *^ S. G. Jewett collection, Portland, Oreg. *^ Univ. Michigan Mus. Zool. ■"iMus. Vert. Zool. *' Carnegie Mus. 1938] REVISION OF THE GROUND SQUIRRELS 207 Nevada (fig. 20). Zonal range: Upper Sonoran, Transition, and Canadian. External chaTacters. — Similar to G. I. chrysodei7nis^ but tail longer and coloration paler; upper parts more grayish (less brownish), es- pecially on the rump; under parts and feet more whitish (less buffy). Compared with C. I. castanuru^H : Upper parts paler (less brownish) ; mantle paler (more ochraceous) ; tail paler beneath. Cranial characters. — Skull closely similar to that of chrysodeirus ; interi^terygoid fossa and nasals averaging slightly narrower. Color. — Summer felage (June-July) : Top of head hazel; sides of head and face, and shoulders, ochraceous tawny, shaded with cinnamon buff; ears cinnamon buff; median dorsal area vinaceous fawn, more or less shaded with grayish white, becoming fawn color or army brown on the rump and thighs; light dorsal stripes creamy white or pinkish buff; both pairs of black stripes of equal width, reaching from shoulders to hips; lower sides pinkish buff or pale pinkish buff; hind feet creamy white or pale pinkish butt'; front feet pinkish butt'; tail above, black, mixed with warm buff and bor- dered with the same; tail beneath, tavrny or cinnamon, bordered with black and edged with warm buff; under parts creamy white, faintly shaded with pale pinkish buff. Winter felage (Ruby Moun- tains, Nev., June 20) : Median dorsal area nearly uniform pale smoke gray, shaded with vinaceous cinnamon on nose and head; mantle nearly obsolete, the shoulders and sides of neck washed with cin- namon butt'. Molt. — In two females from Wliite Pine County, Nev., June 18 and 23, new summer pelage is coming in on the top of the head. Measurementfi. — Average of 10 adults (4 males, 6 females) from type locality: 'I'otal lensth, 208.6 (2r)2-28S) ; tail vertebrae, 101.2 (90-108) ; hind foot. 40.5 (39-44); ear from notch (dry), 13.9 (13-10). Skull: AvcniKe of 7 adults (2 males, 5 females) from type locality: Greatest length, 42.8 (41.8-14) : palatilar length, 19.8 (19-20.2) ; zygomatic breadth, 26.9 (25.6-27.7) ; cranial breadth, 19.8 (19.3-20.S) ; interorbital breadth, 9.5 (9.1-9.8) ; postorbital constriction, V2.2 (11.4-14) ; length of nasals, 14.9 (14.4-15.4) ; maxillary tooth row, 8.4 (8.1- 9.3). Weight. — Average of 10 males from White Mountains, Calif., 182 g (166.5- 199.5) ; of 10 females, 160 g (141-209.1) (Grinnell and Dixon, 1918, p. 682). Remarks. — This race is only slightly different from typical chrysodeirus, being chiefly distinguished by its more whitish feet and under parts. Occasional specimens from within the range of frepidus are difficult to distinguish from chrysodeirus. A large series of ^''perpallidus^^ (topotypes) proves on comparison to be practically identical w^ith trep/dic^. Specimens examined. — Total number, 260, as follows: California: Glass Mountain (Mono Hills, Mono County), 3;** Inyo Mountains, 12; Mammoth (Mono County), 1;^ Mammoth Lakes, 1;'° Sherwin Hill, Round Valley (Mono County), 4;-"* White Mountains, 02.™ Idaho: Albion (Cassia County), 3; Bannock Mountains (8 miles west of Swan Lake), 1 ; Silver City, 10. Nevada: Arc Dome (Toyabe Mountains), 3; Badger (20 miles northwest of Summit Lake, Humboldt County), 2; Baker Creek (White Pine County), 9;" Bull Run Mountaiiis, 1; Carlin, 1;^" Cottonwood Range, 3: Edgewood (Douglas County), 1;" Granite Creek, 5; Lehman Creek (White Pine 4a ripvel.Tnrt I\[us. Nat. Hist. ^8 Univ. MidiiRan Mus. Zool. "> Forty in Mus. Vevt. Zool. ; six in Cleveland Mus. Nat. TTist. " Mus. Vfirt. Zool. ''' Amer. Mus. Nat. Hist. 208 NORTH AMERICAN FAUNA [No. 56 County), 1;^ Little Owyhee River, 9; Monitor Mountains (25 miles south- west of Eureka), 6; Mount Siegel (Douglas County), 4;°" Palisade, 1; Pine Forest Mountains, 37;^^ Reese River (head), 3; Ruby Mountains, 5; Ruby Valley, 1; Stella Lake, Snake Mountains (White Pine County), 11;^' Toyabe Mountains, 4; Virgin Valley, 1;^ Willard Creek (White Pine County), 5". Oregon: Barren Valley (Steens Mountain region), 1; Beulah, 1; Buchanan (Harney County), 7; Burns, 2; Cedar Mountains, -3 ; Cow Creek Lake, 1; Disaster Peak (Malheur Comity), 1; Drewsey (Harney County), 3; Harney (Harney County), 2; Home (Baker County), 2; Huntington, 5: McDermitt Creek (8 miles northeast of McDermitt, Nev.), 3; Mount Warner {— Hart Mountain, Lake County), 1; Riverside (Malheur County), 7; Shirk (6 miles southeast of Blitzen, Harney County), 2; Steens Moun- tains, 2; Westfall (Malheur County), 5. Utah: Raft River Mountains (17 miles northwest of Kelton), 2.°* CITBLLUS LATERALIS CERTUS (Goldman) Charleston Mountains Mantled Ground Squirrel Callospermopliilus lateralis certus Goldman, Jour. Mammal. 2 : 232, Nov. 29, 1921. Type. — Collected at north base of Charleston Peak, Charleston Mountains, Nev., June 29, 1915, by L. J. Goldman; male adult, skin and skull, no. 208891, U. S. Natl Mus. (Biological Survey collection) (orig. no. 2270). Range. — Charleston Mountains, Nev. (fig. 20), Zonal range: Transition. External characters. — Similar to C . I. trepidus, but tail shorter and darker beneath; coloration paler and more grayish (less brownish) ; black dorsal stripes shorter, the inner pair narrower. Compared with 0. I. chrysodeirus : Coloration much paler and more grayish; under parts and feet white instead of buff; tail shorter and darker. Cranial characters. — Skull similar to that of trepidus, but averag- ing slightly narrower across the zygomata; nasals shorter, and narrower posteriorly. Color. — Sicmmer pelage : Head, nape, and shoulders mikado brown, bordered next the throat with warm buff; throat warm buff in some specimens; middle of back and rump smoke gray, mixed with cin- namon drab; light dorsal stripes white, narrowing posteriorly; dark dorsal stripes reduced, the outer pair scarcely reaching the hips, the inner pair narrovrer and still shorter; hind legs washed with mikado brown; hind feet creamy white or pale pinkish buff; front feet pinkish buff or pale pinkish buff; tail above, black, edged with ochraceous buff'; tail beneath, russet or tawny, bordered with black and edged with ochraceous buff; under parts creamy white. 'Winter pelage: Not seen, but a specimen in changing pelage (June 29) in- dicates that the head is drab gray and the mantle mostly obsolete. Molt. — Specimens taken at the type locality, June 29 and 30 and July 2 are in process of molting ; on some, the heads still retain some of the old winter pelage, the new hair coming in in patches ; a male taken July 6 has the entire mantle in summer pelage, the rest of the body in winter pelage. Measurements. — Average of 18 adults (7 males, 11 females) from type locality: Total length, 249 (280-258) : tail vertebrae, 77.4 (70-90) ; hind foot, 38.5 (35-41) ; ear from notch (dry), 15.1 (14-16.5). Skull: Average of 6 males (adult and subadult) from type locality: Greatest length, 42.5 (41—43.4); palatilar length, 19.9 (19-20.5) ; zygomatic breadth, 26 (25-27.2) ; cranial breadth, 19.9 (19.3-20.3) ; interorbital breadth, 9.8 (9.2-10.4) ; postorbital con- ^ Mus. Vert. Zool. ^=Amer. Mus. Nat. Hist. 1938] REVISION OF THE GROUND SQUIRRELS 209 striction, 13.2 (12.S-13.8) ; length of nasals, 13.8 (13.3-14.2) ; maxillary tooth row, 8.1 (7.8-8.6). Average of 7 adult females; Greatest length, 41.7 (41-42.8) ; palatilar length, 19 (18-20) ; zygomatic breadth, 25.2 (24.4-25.7) ; cranial breadth, 19.5 (19-20) ; interorbital breadth, 9.4 (8.9-9.6), postorbital constric- tion, 12.9 (12.2-13.5) ; length of nasals, 13.7 (12.8-14.4) ; maxillary tooth row, 8.3 (7.7-8.7). Remarks. — Isolated on the Charleston Mountains, this short-tailed pale race is nearest to treindus of the region to the northward ; al- though in general coloration it is among the palest of the races, its tail is as dark as in any of the subspecies. Specimens examined. — Total number, 21,°^ from type locality. CITELLUS LATERALIS BERNARDINUS (MEauoAM) San Bebnakdino Mantled Ground Squirrel SpermopJiiliis chrysodcirus brevicaudns Merriam, Biol. Soc. Wash. Proc. 8: 134, 1893 (not Bpermopliilus hrcvicauda Brandt, 1884). Spcrmophilus (Callospennopliilus) hcrnardinus Merriam, Science (n. s.) 8: 782, Dec. 2, 1898 (substitute for Irevicaudus) . Callospermophilus hernardinus Mearns, U. S. Natl. Mus. Bull. 56: 313, 1907. Citellus chrysodeirus 'hernardinus Elliot, Field Columb. Mus. Pub., Zool. Ser. 6: 107, 1905. Type. — Collected on San Bernardino Peak, Calif., October 9, 1893, by J. E. McLellan; female subadult, skin and skull, no. 56661, U. S. Natl, Mus. (Biological Survey collection) (orig. no. 274). Range. — San Bernardino Mountains (6,700-11,485 feet, fide Grin- nell) (fig. 20). Zonal range: Canadian and Hudsonian. External characters. — Closely similar in summer pelage to C. I. clirysodevnis., but mantle averaging slightly darker, especially on the nape; in winter pelage upper parts more grayish (less vinaceous) ; under parts slightly paler (less buffy) ; tail shorter; hind foot longer. Cranial characters. — Skull similar to that of chrysodeirus, but averaging slightly larger, with longer nasals. Color. — Summer pelage: Top of head and face pecan brown or mikado brown, this color reaching on to the back between the shoul- ders; sides of head and neck ochraceous tawny; median dorsal area fawn color or smoke gray; chin and throat pale pinkish buflf; belly creamy white; tail beneath, tawny. Winter pelage (June) : General, tone grayish (decidedly different from the summer pelage) ; mantle only faintly indicated and much paler; top of head and face cinna- mon; sides of head, neck, and shoulders ochraceous buff; dorsal area smoke gray, shaded with cinnamon drab; sides grayish white; feet grayish white, faintly washed with pale pinkish buff; tail as in summer. Molt. — A male taken June 19 shows fresh summer pelage covering the head and neck, tlie rest of the body being in worn winter pelage ; a female taken June 28 shows new pelage covering the nose and face, reaching to the ears. Measurements. — Average of 7 adult males from San Bernardino Mountains : Total length, 255 (240-205) ; tail vertebrae, 77.3 (70-84) ; hind foot, 42 (40- 45) ; ear from notch (dry), 15.4 (15-16). Average of 10 adult females: Total length, 249.5 (239-272) ; tail vertebrae, 71.1 (03-80) ; hind foot, 40.2 (.3&-42) ; ear from notch, 15.6 (14-16.5). Skull: Average of 9 adult males: Greatest length, 42.8 (41.8-43.7) ; palatilar length, 19.5 (19-20) ; zygomatic breadth, 26.0 (26-27.8) ; cranial breadth, 19.2 (18.7-19.5) ; interorbital breadth, 10.7 (10.1- " Seventeen in D. R. Dickey collection. 154970—38 14 210 NORTH AMERICAN FAUNA [No. 56 11.6) ; postorbital constriction, 12.9 (12.5-13.7) ; length of nasals, 15.7 (14.8- 16.7); maxillary tooth row, 8.3 (7.9-8.8). Average of 10 adnlt females: Greatest length, 42 (40.4-44) ; palatilar length, 19.1 (18.5-20) ; zygomatic breadth, 25.8 (24.9-26.8) ; cranial breadth, 19 (18.6-19.7) ; interorbital breadth, 10.2 (9.4-10.8) ; postorbital constriction, 12.8 (11.9-13.7) ; length of nasals, 15.4 (14.1-16.3) ; maxillary tooth row, 8.1 (7.5-8.5). Remarks. — Altliough geographically isolated from chrysodeirus^ this race is so close to the latter in characters that a subspecific desig- nation seems best to express its relationship. As pointed out under chrysodeirus, specimens of that race from the southern Sierra Nevada approach herna^rdinus in certain characters. Specimens examined. — Total number, 49, as follows : California: Big Bear Lake (San Bernardino County), 1; San Bernardino Mountains, 48. CITELLUS LATERALIS MITRATUS (Howell) YoixA BoiXY Mantled Ground Squirrel (Pis., 27, A; 32, A) Callospermophihis chrysodeirus mitratus Howell, Jour. Mammal. 12 : 161, May 14, 1931. Type. — Collected on South Yolla Bolly Mountain, Calif., July 30, 1905, by J. F. Ferry; male adult, skin and skull, no. 138125, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 13). Range. — Coast ranges of northern California, from Glenn County north to southern Siskiyou County (fig. 20). Zonal range: Canadian and Transition, External characters. — Similar to C. I. chrysodeirus., but upper parts paler and more grayish (less brownish), especially on the rump ; mantle darker, especially on sides of head and on shoulders ; tail averaging longer and darker beneath; hind feet longer. Com- pared with C. I. trinitatis: Upper parts much paler; mantle deeper colored and more extensive ; external measurements smaller. Cranial characters. — Skull larger than that of chrysodeiriis., with longer nasals. Compared with trinitatis: Skull about same length, but zygomata more widely expanded posteriorly and nasals longer. Color. — Summer pelage : Head and mantle russet, this color extend- ing on to the shoulders and fore back, shaded on sides with ochra- ceous tawny ; throat and sides of nose Avarm buff ; ears russet, shaded with ochraceous tawny; eye ring buffy white; median dorsal area smoke gray, shading in some specimens to army brown on rump and thighs ; light dorsal stripes creamy white ; sides of body pinkish buff ; feet cinnamon buff; tail above, black or fuscous black, mixed with warm buff; tail beneath, taAvny, bordered with fuscous black and edged with warm buff; under parts pinkish buff, shading to warm buff. Winter pelage (September 26) : Head sayal brown or mikado brown ; mantle nearly obsolete ; sides of neck clay color, washed with dull tawny; otherwise as in sununer. Molt. — Two adult females from Canyon Creek, Calif., taken August 21, show new pelage coming in on the head and the middle of the back. Measurements.— ANQVBige of 10 adults (5 males, 5 females) from type locality (including 2 from Grindstone Creek, northern Glenn County) : Total length, 269 (254-283) ; tail vertebrae, 94.1 (81-110) ; hind foot, 41.4 (40-43) ; ear from notch, 14.5 (13-10). Skull: Average of 8 adults (5 males, 3 females) from 1938] REVISION OF THE GROUND SQUIRRELS 211 same localities: Greatest length, 43.5 (42^44.4) ; palatilar lengtli, 20.3 (19.8- 20.5) ; zygomatic breadth, 27.5 (26.8-28.4) ; cranial breadth, 19.9 (19.3-20.8) ; interorbital breadth, 10.1 (10-10.9) ; postorbital constriction, 12.7 (12.4-13.2) ; length of nasals, 15.7 (15.3-16.6) ; maxiUary tooth row, 8.1 (7.6-8.7). Remarks. — This race is most strongly developed in the vicinity of South Yolla Bolly Mountain. The specimens from northern Trinity and southern Siskiyou Counties agree in size with typical mitra- tus but are slightly darker; the skulls average a little longer, and narrower across the zygomata, thus showing approach to trinitatis. Specimens from Bear Creek in the northeastern corner of Trinity County show approach to chrysodeirus in small average size of the skulls. Specimens examined. — Total number, 83, as follows: California: Bear Creek (head. Trinity County), 11;" Canyon Creek (Trinity County), 4; Castle Lake (Siskiyou County), 2;^ Coast Range (17 miles west of Paskenta, Tehama County), 1; Coffee Creek (North Fork, Trinity County), 3;"* Grindstone Creek (Tehama County), 2; Grizzly Creek (head. Trinity County), 5;" Jackson Lake (Siskiyou County), 5;" Kangaroo Creek (Siskiyou County), 1;^ Rush Creek (head, Siskiyou County), 6;" Salmon Mountains (near Etna Mills), 11; Salmon River (South Fork, Siskiyou Mountains), 8;" Saloon Creek Divide (Si.skiyou County), 11;^* South Yolla Bolly Mountain, 10; Wildcat Peak (Siskiyou County), 3.=' CITELLUS LATERALIS TRINITATIS (Merriam) Trinity Mountains Mantleh) Ground Squirrel Callospermophiliis chrysodeirus trhiitutis Merriam, Biol. Soc. Wash. Proc. 14: 126, July 19, 1901. Citellus chrysodeirus trinitatis Elliot, Field Columb. Mus. Pub., Zool. Ser. 6: 107, 1905. Type. — Collected at 5,700 feet altitude in the Trinity Mountains, east of Hoopa Valley, Calif., September 10, 1898, by Vernon Bailey; female adult, skin and skidl, no. 95531, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 6693). Range. — Trinity Mountains in northern Humboldt County, north through the Siskiyou Mountains to southwestern Oregon (fig. 20). Zonal range: Canadian and Transition. Exteimal characters. — Similar to G . I. chrysodeinis but darker and more brownish above, particularly on the rump; mantle averaging slightly darker; sides of head and neck darker; tail averaging darker beneath; external measurements greater. Cranial characters. — Skull similar to that of chrysodeirus but aver- aging longer and relatively narrower, the zygomata less expanded posteriorly. Color. — Summer pelage (September 10) : Top of head russet, this color reaching over the crown and middle of tlie nape, and on sides of head from the eyes to the shoulders, bordered next the throat with cinnamon buff or clay color; shoulders more or less shaded with ochraceous tawny; ears russet to ochraceous tawny; light dorsal stripes ochraceous buff on the shoulders, creamy wliite for the rest of their length, reaching to the hips but not on to the rump; median dorsal area fawn color, shading to natal brown on rump and thighs; both pairs of black stripes equal in width and nearly equal in length to white stripes; lower sides and under parts pinkish buff or warm "Mus. Vert. Zool. 212 - NORTH AMERICAN FAUNA [No. 56 buff; feet cinnamon buff; tail above, black mixed with ochraceous tawny ; tail beneath, tawny or bay edged with black and ochraceous tawny. Measurements. — Average of 6 adults (3 males, 3 females) from type locality: Total length, 2S1.3 (26{>-295) ; tail vertebrae, 90.7 (91-109) ; hind foot, 43.2 (41-44) ; ear from notch, 15.2 (14.5^16.5). Skull: Average of 9 adults (5 males, 4 females) from type locality and (3 females) from Siskiyou Mountains : Great- est length, 43.1 (41.2-44.8) ; paJatilar length, 19.8 (19'-21) ; zygomatic breadth, 25.8 (24.8-27.5) ; cranial breadth, 19.4 (19.1-19.9) ; interorbital breadth, 9.9 (8.8^11) ; postorbital constriction, 12.9 (12.2-14.4) ; length of nasals, 14.9 (14.- 15.8) ; maxillary tooth row, 8 (7.6-8.7). Remarks. — This, the darkest race of the chi^ysodeims group, occu- pies a rather limited range in the coast mountains of northwestern California, intergrading with C. I. iiiitratus to the eastward. Specimens examined. — Total number, 30, as follows : California: Preston Peak, 3; Siskiyou Moimtains, 15; Trinity Mountains (east of Hoopa Valley), 10. Oregon: Briggs Creek (13 miles southwest of Galice), 1; Siskiyou, 1. CITELLUS SATURATUS (Rhoads) Cascade Mantled Ground Squirrel Tamias lateralis satnratus Rhoads, Acad. Nat. Sci. Phila. Proc. 1895: 43, April 9. [Spermophilus lateralis] satnratus Elliot, Field Colunib. Mus. Pub., Zool. Ser. 2 : 83, 1901. Cltellus lateralis satnratus Elliot, Field Culumb. Mus. Pub., Zool. Ser. 6: 106, 1905. C alios permophilus lateralis satnratus Miller, U. S. Natl. Mus. Bull. 79: 316, 1912. Type. — Collected at Lake Kichelos [=Keeclielus], Kittitas County, Wash. (8,000 feet altitude), September 1893, by Allan Rupert; male adult, skin and skull, no. 8365, Acad. Nat. Sci. Phila. (no. 1365, Ehoads collection). Range. — The Cascade Mountain region of western Washington and southern British Columbia; north to Tulameen, British Columbia; south to the Columbia River Valley, southern Washington; east to the Similkameen River, British Coliunbia (fig. 20). Zonal range: Canadian. External characters. — Size largest of the subgenus ; coloration very similar to that of C. lateralis loMralis., but slightly darker, especially on the head, rimip, and thighs ; mantle not Avell defined ; under parts more buffy (less whitish) ; median pair of dark stripes obsolete or much reduced and outer pair reduced in length and obscurely defined. Cranial characters. — Skull similar to that of lateralis but decidedly larger in all measurements except the nasals, which are practically the same length. Compared with G . I. chrysodeirus and G . I. tesco- rum: Size much larger with longer rostrum and nasals. Golor. — Fresh summer pelage: Top and sides of head russet or mikado brown, bordered next the throat with cinnamon buff; shoul- ders russet, shaded with ochraceous tawny; ears tawny, shading to pinkish buff on posterior margin; eye ring pinkish buff; median dorsal area fawn color or hair brown; hips and thighs army brown; light dorsal stripes dull buffy white; outer pair of dark stripes black or fuscous black, washed with tawny; inner pair absent or faintly indicated; sides Avarm buff; front feet cinnamon buff; hind feet pinkish buff; tail above, black, mixed with cinnamon buff; tail be- 1938] REVISION OF THE GROUND PQUIRRELS 213 reath, cinnamon or cinnamon buff, more or less mixed with black; imder parts cinnamon buff. Molt. — The annual molt takes place in June or July; four speci- mens from Trout Lake, Wash., June 27 and 28, show fresh pelage covering the head and shoulders, the remaining parts of the body being in a worn and faded pelage. Measurements. — Average of 10 adult males from the Cascade Moimtaius, Wash.: Total length, 305 (2S7-315) ; tail vertebrae, 110.9 (100-118) ; hind foot, 46.5 (44-49) ; ear from notch (dry), 17 (1&-18). Average of 10 adult females from same localities: Total length, 300 (286-312); tail vertebrae, 106.5 (92- 116); hind foot, 45.4 (43-48); ear from notch (dry), 17.8 (17-18.5). Skull: Average of 10 adult males from the Cascades : Greatest length, 46.4 (44-48.3) ; palatilar length. 21.4 (20-22.5) ; zygomatic breadth, 28.9 (27.7-30.4) ; cranial breadth, 20.4 (19.5-20.9) ; interorbital breadth, 11.5 (10.9-12.3) ; postorbital constriction, 13.4 (12.9-14.2) ; length of nasals, 16.8 (15.8-17.7) ; maxillary tooth row, 8.9 (8.1-9.5) ; average of 10 adult females from same localities: Greatest length, 45.2 (43.9-46.3) ; palatilar length, 20.8 (20-21.3) ; zygomatic breadth, 28.1 (27.2-28.6) ; cranial breadth, 19.9 (19.5-20.2) ; interorbital breadth, 11 (10.6-11.6) : postorbital constriction, 13.3 (12.4-14) ; length of nasals, 16 (15.6- 16.6) ; maxillary tooth row, 9 (8.6-9.6). Remarks. — The Cascade mantled ground squirrel differs so mark- edly from the other members of the subgenus that it seems necessary to regard it as a full species. It resembles O. lateralis lateralis of Colorado more nearly than any of the other races, but is widely separated from it geographically. It is very different from chryso- deirus., whose range it nearly meets but from which it is separated by the Columbia River. So far as known, there is a wide gap in British Columbia between the range of saturatus and that of tes- cor^im and the two forms are very dissimilar in their characters. Specimens examined. — Total number, 111, as follows: British Columbia: Hedley, 5;" Hope-Princeton Summit, 3;" Keremeos (Ash- nola Creek), 2;^^ Lightning Lakes (near Boundary Momunent 77, Yale District), 1; Second Summit (west of Skagit River), 5;" Skagit River, 1;'° Tulameen, 1;^ Whipsaw Creek (branch of Similkameon River), 1." Washington: Bald Mountain (Okanogan County), 1; Barron (Whatcom Coun- ty), 5; Bauerman Ridge (Okanogan County), 1; Bmnping Lake (Yakima County), 1; Cleveland (Klickitat County), 1; Easton, 18; (JoUleiulalo, 4; Hannegan Pass (Wliatcom County), 1; Hart Lake (Chelan County), 1; Keechelus (Kittitas County), 3; Keechelus Lake, 1; Lake Cli(>lan, 1; Ma- zama (Okanogan County), 1; Mount Adams, 2; Mount Aix, 1; Mount Rainier, 10: Mount St. Helens, 3; Rainier Fork Ridge, 4; Spray Park (Pierce County), 1;" Stehekin (head of Lake Chelan), 2; "Tannum River" (=Bumping River), 1: Trout Lake (Klickitat County), 13; Wenatcbce, 3; Wenatchee i[jake, 1; Whipsaw Creek (branch of Similkameen River), 1 ;'^'' Yakima Indian Reservation (Signal Peak), 5. CITELLUS MADRENSIS (Mbrriam) SiFRRA Madre Ma nixed Ground Squirket, (Pis. 27, B; Z2, B) Callnspermophiltis madrensis Merriam, Wash. Acad. Sci. Proc. 3 : 563, Nov. 29, 1901. [Citrllus] madrensis Elliot, Field Columb. Mus. I'ub., Zool. Ser. 4: 147, 1904. Type. — Collected in the Sierra Madre, near Guadalupe y Calvo, Chiiiuahua, Mexico (7,000 feet altitude), August 27, 1898, by E. W. '•'' Natl. Mus. Canada. B» Provincial Mu.s., Victoria, British Columbia. *^ Univ. IMicliiKiUi Mu.s. /ool. 214 NORTH AMERICAN FAUNA [No. 56 Nelson and E. A. Goldman; female adult, skin and skull, no. 95363, U. S. Natl. Mus. (Biological Survey collection) (orig. no. 12923), Range. — Sierre Madre, Mexico, from northwestern Durango north to latitude 27°, west of Batopilas, Chihuahua; limits of range not known (fig. 20). Zonal range: Transition. External characters. — Similar to C . lateralis lateralis and G. I. arizonensis., but smaller, with much shorter tail ; colors much duller, with scarcely any trace of a mantle; black stripes short and poorly defined, tending to become obsolete ; white stripes reaching nearly to the root of the tail. Cranial characters. — Skull similar to that of lateralis but smaller and relatively narrower; zygomata more appressed; brain case nar- rower and more highly arched. Color. — Worn simimer pelage (August 26-September 3) ; Head and face hazel or sayal brown; eye ring buffy white; lower cheeks, sides of lips, and fore legs warm buff ; sides of neck and shoulders rather faintly washed with cinnamon buff and ochraceous tawny; ears thinly clothed on outer surface with cinnamon hairs; general tone of upper parts cinnamon drab or fawn color, darkest and purest on rump and thighs; light dorsal stripes dull whitish or pinkish buff; dark stripes blackish, often very faintly indicated; sides of body cinnamon buff or buffy white ; tail above, fuscous black, mixed with warm buff ; tail beneath, warm buff, tipped with blackish ; hind feet pinkish buff; under parts pinkish buff or buffy white. Measurements. — Average of 10 adults (3 males, 7 females) from type local- ity: Total length, 227.8 (215-243) ; tail vertebrae, 58.8 (52-66) ; hind foot, 38.7 (37-40) ; ear from notch (dry), 16.4 (15-18). ^kull: Average of 7 adults (2 males, 5 females) : Greatest length, 42.3 (41.1-44.1) ; palatilar length, 20.1 (19.5-20.5) ; zygomatic breadth, 25.6 (24.8-26.5) ; cranial breadth, 18.9 (18.5- 19.3) ; interorbital breadth, 10.2 (9.9-10.5) ; postorbital constriction, 12.3 (11.9- 12.7) ; length of nasals, 15.8 (15.1-17) ; maxillary tooth row, 8.5 (8.3-8.7). Remarhs. — The Sierra Madre ground squirrel, although clearly derived from the C. I. lateralis stock, has become so strongly differ- entiated that it must be treated as a distinct species. The known range of tnadrensis is separated from that of arizonensis by a gap of about 500 miles, though further collecting in the Sierra Madre may somewhat extend the range of the present form northward. E. W. Nelson, who discovered the species, writes of its habits at the type locality as follows : Very abundant in the pine woods about the base of Mohinora and reaches the extreme summit of the moimtains. We saw them all along our route from above Guanacevi In Durango to Guadalupe y Calvo. Their range extends only a little below 7,000 feet and does not enter the pinyou belt. Specimens examined. — Total number, 21, from type locality. FOSSIL SPECIES Eight fossil forms in the genus Citellus have been described from North America. Of these, two are from Miocene formations, two from the Pliocene, and four from the Pleistocene. The most primitive species at present known is Citellus {Protosper- mophilus) quatalensis Gazin (1930, p. 64), from Quatal Canyon, 8 1938] REVISION OF THE GROUND SQUIRRELS 215 miles east of Cuyama Valley, Calif. Of this Miocene form the de- scriber says : On the basis of available material, Citellus (Protospcnuophilus) quatalcnsis appears to resemble the Recent genus or subgenus OtospermopMlus more nearly than it does any of the other sciurids. Moreover, the new form presents an association of primitive characters which suggests that the dentition possessed by the modern otospermophilids is more primitive than that exhibited by the typical citellids. This is also indicated by the development of the premolars, which in the case of typical CiteUiis appear to have taken on more completely the characters of the molar teeth. From this consideration it seems probable that species of Citellus may have been derived from an Otospermophilus-like ancestor, probably later than the stage represented by C. (P.) quatalensis, assuming this form to be in or near the line of descent of the ground squirrels. Citellus 7'idgirayi Gazin (1932, p. 61), from the Skiill Spring Miocene beds, Malheur County, Oreg., is about the size of Citellus {Callosper?nophilus) chrysodeirus and resembles that species perhaps as nearly as it does any living form. It, shows conspicuous differ- ences, however, and cannot with certainty be assigned to any of the modern subgenera. Compared with CaUosiyermophilus the skull of C. ridgwayi is flatter on the superior surface and wider between the orbits. "The outer and anterior margin of the zygoma . . . con- tinues forward on the side of the muzzle as a small ridge, following the contour of the incisor to the alveolus" (Gazin). The molars are low-crowned, as in CallospermopMlus ; ;;»*, 7;i\ and w- are broader than long, and differ from the teeth of CallospermopMlus in having a much less prominent i^arastyle. On m ^ and m - the protoloph and metaloph are not parallel as in C alios permophiluJi^ but converge toward the inner side as they join the protocone. ]\P has a reduced parastyle, a prominent protoloph, and a slight ridge in the basin of the tooth running toward the metacone. OtospermopMlus gidleyl Morriam, Stock, and INIoody (1925, p. 68), from the Kattlcsnake Pliocene, John Day Valley, Oreg., is thus char- acterized by the descri))prs: It is clearly distinguished from the other sciurids by the combined char- acters of the relatively shorter anteroposterior extent of all the cheek teeth. ... A charnctcr which seems to distinguish the fossil distinctly from the living species of the citellid group is the much greater relative depth aud apparently shorter proportions of the lower jaw. Citellus hensoni Gidley (1922, p. 122), from the San Pedro Valley, Ariz. (Pliocene), was described from the molars only; as stated by Gidley, these teeth seem most nearly like those of OtospermopMlus ; the u])per molars are relatively narrow in the transverse diameter, and the posterior loph is "broken up into two distinct but slightly joined cuspules, the inner one of which is a rounded cone entirely disconnected from the protocone." Citellus tuitus Hay (1921, p. 627), from Val Verde Mine, Ariz. (Pleistocene), Avas compared by the describer with C, franJdinii, but it seems to be nearer to C. mexicanus ; the tooth rows converge pos- teriorly about as in that species; the molars are higher-crowned on the inner side; mi' is longer llian broad (nearly quadrate in mexi- ca.'ims). Except for the more hypsodont molars, (his species might be referred to the subgenus Ictidomys. Citellus coeMj, OALLOSPERMOPHILUS, WITH A NOTE ON ITS ANAL GLAND. Jour. Morph. and Physiol. 42: 441-451. 1927. NOTES ON THE GROUND SQUIRREL, CALLOSPERMOPHILUS. Mich. Univ., MuS. Zool. 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MOISTURE AND ALTITUDE AS FACTORS IN DETEIRMINING THE SEASONAL ACTIVITIES OF THE TOWNSEND GROUND SQUIRREL IN WASHINGTON. Ecology 2 : 189-192, illus. 1924. THE HOME LIFE OF THE COLUMBIAN GROUND SQUIRREL. Cauad. Field Nat. 38: 128-130, 151-153, illus. 1925a. DURATION OF THE AESTIVATION AND HIBERNATION OF THE COLUMBIAN GROUND SQUIRREL (CITEILLU& COLUMBIANUS) AND SEX RBXATION TO THE SAME. Ecology 6: 75-81, illus. 1925b. THE HIBERNATION OF THE COLUMBIAN GROUND SQUIRREL. Caiiad. Field Nat. 39: 56-61, 79-82, illus. 1925c. THE SEASONAL DIFFERENCES OF NORTH AND SOUTH SLOPES IN CONTROL- LING THE ACTIVITIES OF THE COLUMBIAN GROUND SQUIRREL. EcOlOgy 6: 157-162, illus. 1925d. BREEDING AND DEVELOPMENT OF THE COLUMBIAN GROUND SQUIRREL. Jour. Mammal. 6: 106-113. illus. 1925e. THE COLUMBIAN GROUND SQUIRREL AS A HANDLER OF EARTH. Sci. Monthly 20: 483-490, illus. 1925f. TRACKING THE COLUMBIAN GROUND SQUIRREL TO ITS BURROW. Natl. Geogr. Mag. 47: 587-596, illus. 1925g. THE FOOD OF GROUND SQUIRRELS. Amcr. Nat. 59 : 250-264, illus. 1925h. A LIFE HISTORY PROBLEM AND A MEANS FOR THE SOLUTION. Jour. Mammal. 6: 157-162, illus. 19251. OBSERVATIONS ON THE HIBERNATION OF GROUND SQUIRRELS. JOUr. Agr. Research 31 : 761-769, illus. 1926a. A SHORT 8E.\S0N AND ITS EFFECT UPON THE PREPARATION FOR REPRODUC- TION BY THE COLUMBIAN GROUND SQUIRREL. ECOlOgy 7 : 136-139, illus. 1926b. AGE OF THE ANIMAL AND SLOPE OF THE GROUND SURFACE. FACTORS MODI- FYING THE STRUCTURE OF HIBERNATION DENS OF GROUND SQUIRRELS. Jour. Mammal. 7 : 91-96, illus. 1926c. THE STORING HABITS OF THE COLUMBIAN GROUND SQUIRREL. Anier. Nat. 60: 367-373. Slack, J. H. 1861. DESCRIPTION OF A NEW SPECIES OF RODENT OF THE GENUS SPERMOPHILUS. Acad. Nat. Sci. Phila. Proc. 1861 : 314. Sleogs, Geokgb Frederick. 1026. the adult anatomy and histology of the anal glands of the rich- ardson ground squirrel, citkllus richardsonii sabine. auat. rec. 32: 1-43. Stephens, Frank. 1906. CALIFORNIA MAMMALS. 351 pp., iUus. Sau Diego. Stonex Witmek. 1908. THE MAAfMALS OF NEW JERSEY. N. J. State Mus. Auu. Rept. 1907, 211 pp., illus. Storer, Tracy Irwin. 1029. SXTMMER and autumn breeding OF the CATJFORNIA GROUND SQIHRREX, Jour. Manuunl. 10: 2.3.")-23(!. 226 NORTH AMERICAN FAUNA [No. 56 Strong, Richabd Peabson. 1923. kesearch in some aspects of disease associated with the fields of GEiOLOGY, ENTOMOLOGY, AND PAKAsiTOLOGY. Science (n. s. ) 57: 507-520. SUBBEB, THADDEUS. 1932. THE MAMMALS OF MINNESOTA. 84 pp. illus. St. Paul. (Bull. Minn. Dept. Conserv., Div. of Game and Fish). SVIHLA, AbTHTJB. 1931. oallospebmophilus climbing tbees. Murrelet 12 : 80'. 1933. OCCUBBENCEI OF A COLONY OF ALBINO GBOUND SQUIRREILS NEAR PULLMAN, WASHINGTON. Murrclct 14 : 78. SWABTH, HaBEY SCHEXWALD. 1929. THE FAXJNAL AREIAS OF SOUTHERN ABIZONA : A STUDY IN ANIMAL DISTRI- BUTION. Calif. Acad. Sci. Proc. (4) 18 : 267-383, illus. Taylob, Walter Penn. 1910. TWO NEW RODENTS FROM NEivADA. Calif. Univ. Pubs., Zool, 5 : 283-302, illus. 1911. MAMMALS OF THE ALEXANDER NEVADA EXPEDITION OF 1909. Calif. UniV. Pubs., Zool. 7 : 205-307. 1916. A NEW SPERMOPHILE FROM THE SAN JOAQUIN VALLEY, CALIFORNIA, WITH NOTES ON AMMOSPEEMOPHILUS NELSONI MEBRIAM. Calif. UniV. Pubs., Zool. 17: 15-20, illus. Thomas, Oldfiesld. 1915. THE PENIS-BONE, OR "BACULUM", AS A GUIDE TO THE CLASSIFICATION OP CERTAIN SQUIRRELS. Ann. and Mag. Nat. Hist. (8) 15:383-387. 1927. A SELECTION OF LEICTOTTPES OF AMERICAN BODENTS IN THE COLLEiCTION OF THE BBiTisH MUSEUM. Ann. and Mag. Nat. Hist. (9) 19: 545-554. Town SEND, John Kirk. 1839. NARRATIVE OF A JOURNEY ACROSS THE ROCKY MOUNTAINS TO THE COLUM- BIA BIVEB, AND A VISIT TO THE SANDWICH ISLANDS, CHILI, &C. WITH A sciENTTFic APPENDIX. 352 pp. Philadelphia. Wade, Otis. 1927. breeding habits and eably life of the thirteen-striped ground SQUIRREL, CITELLUS TBIDECEMUNEATUS (MITCHILL) . JOUT. Mammal. 8: 269^276. 1980. THE BEHAVIOR OF CERTAIN SPEBMOPHILES WITH SPECIAL EEFEBENCE TO AESTIVATION AND HiBEatNATiON. Jour. Mammal. 11 : 160-188. Ward, Henry L. 1891. DESCRIPTION OF TWO NEW SPECIES OF BODENTS FBOM MEXICO. Amer. Nat. 25: 158-161. Warren, Edward Royal. 1910. THE MAMMALS OF COLORADO. 300 pp., illus. New York. 1924. GROUND SQUIRRELS AND WEASELS. JouT. Mammal. 5 : 265. Wood, Frank Elmer. 1910. a study of the mammals of champaign county, illinois. 111. state Lab. Nat. Hist. Bull. 8 : 501-613, illus. Plate 14 (Natural size) A. Citellus (CaUospermophilus) saturatus. B. Citellus {Poliocitelliis) franklinii. C. Citellus (Ictidomys) tridecemlineatus. D. Citellus (Xerospennophilus) mohavensis. E. Citellus {Citellus) citellus. F. Citellus (Citellus) fulvus. G. Cynomys (Cynomys) ludovicianus. H. Citellus {Citellus) parryii. 228 North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey Plate 14 Skulls of citellus and cynomys. North American Fauna No. 56, U. S. Dept. of Agriculture. Biological Survey PLATE 15 Skulls of Glaucomys. tamias. Eutamias. Sciurus, Microsciurus and ClTELLUS. Plate 15 (Natural size) A. Olaucomys volans volans. B. Tamias striatus. C. Eutamias (Neotamias) dorsaUs. D. Microsciurtis browni. E. Citellus {AmiHOspennophilus} harrisii. F. Citellus iOtoftpermophilus) variegatus grammurus. G. Seiurus ( HeHprrosriuni-s)grixrux. H. Sciurus (Neosciurus) carolinensis. 229 Plate 16 (Natural size) A. Syntheosciunis brochns. B. Sciurus (GuerlingMetus) aestuans cMriquensis. C. Sciurus (Parasciurus) niger limitis. D. Tamiasciurus douglasii. E. Sciurus (Otosciurus) aberti. F. Sciurus (Sciurus) vulgaris. 230 North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey PLATE 16 Skulls of Sciurus, Tamiasciurus, and Syntheosciurus. North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey PLATE 17 Skulls of citellus and cynomys Plate 17 (Natural size) A. Citellus (CalJosprrDiopJiiltis) saturatus- B. CitvUu.'i iPoliofitcllKs) fnmkUiiii. C. Citellus (Ictidonn/s) tritlecemliiicatus. D. Citcllua ( Xcrosprrniopli ilus) mohavensis. E. Citellus iCitrllii.s) citrlhis. F. Citellus {Citellus) fulrus. G. Cynomys (Cytioinys) ludorieiainis. H. Citellus {Citellus) pnrryii. 231 Plate IS (Natural size) A. Glaucomys voians volaiis. B. Tamias striatus. C. Eutaniias (Neotamias) dorsalis. D. Microsciurtis hrowni. E. Citellus {Aminospermopliilus) harrisii. F. Citellus (OtospermopJiilus) variegatus grammnrus. G. Sciiirus (Hesperosciurus) griseus. H. Sckirus (Neosciiirus) carolinensis. 232 North American Fauna No. 56, U. S. Dept. of Agriculture. Biological Survey PLATE 18 Skulls of Glaucomys. tamias. eutamias. Sciurus, Microsciurus, and ClTELLUS. North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey PLATE 19 SKULLS OF SCIURUS. TAM I ASCI URUS, AND SYNTHEOSCI U RUS. Plate 19 (Natural size) A. Synthcosciuriis brochus. B. Sciurus {G-uerlinguetus) aestuans chiriquensis. C. Sciurus (Parasciurus) niger limitis. D. Tamiasciurus douylasii. E. Sciurus {Otosciurus) abcrti. F. Sciurus (Sciurus) vulgaris. 233 Plate 20 (Natural size* A. Cynomys (Ci/noniys) ludoviciantis. B. Citellus {Xerospermophiliis) mohavensis. C. Citellus (CallospermophUus) saturatiis. D. Citelhis {Citellus) citellus. E. Citellus (Poliocitellus) franklinii. F. Citellus (Citellus) parryii. G. Citellus (Citellus) fulvus. H. Citellus (Ictidomys) tridecemlineatus. 234 North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey Plate 20 ^^^^^^m '* ^^^^1 ^^^^^^r "* fl ^^^^^^^^^^^^^r ^^1 ^r ^ 1 ^^^V '-'^ fl H^^^^^B I^^^H M ^^^^^m ^%*3^^B ^^^1 ^^^H ^^v "* .^^H H UJ 1 North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey Plate 21 Plate 21 (Natural size) A. Sciiirus (Hcipcrosci lints) grincuH. B. Microsci lints hroinii. V. Glaiicomys volans. D. Citellits (AniiiiospennopJiilus) han-isii. E. Tamias stiiaiiix. F. i^ciitrus (Xcoxciiinis) caroJiurnsis. G. CltelluH {Otoxiicniiit/jhiliis) ritrietjatita ijnniuininis. H. Eutaniias (NvotumiiDi) dorsalis. 235 Plate 22 (Natural size) A. Bciurus (Otosciunis) aberti. B. Sciurus (Parasciiirtis) niger. C. Syntheoscmrus hrochus. D. Sciurus (Sciurus) rulgaris. E. Tamiasciurus dougJasii. F. Sciurus (Guerlinguetiis) aestuaus. 236 North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey PLATE 22 North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey PLATE 23 Skulls of citellus. Plate 23 (Natural size) 'A. Citelhis toinisevdii niolli.'i. S ad., Fairfield, Utah (no. 30144, U. S. Natl. Mus., Biological Survey collection ) . B. Citcllus idahoriisi.s. $ ad.. Nanipa. Idaho (no. lG8r.ll, IT. S. Natl. Mus., Biological Survey collection). C. Citcllus va.fhiii!/t()iii inixhiiKjtoiii. S ad.. Wallnla. Wa.'^h. (no. Li:>r)732, U. S. Natl. Mu.s., Biological Survey collection). D. Citcllus hruinicus, S ad., Weiser, Idaho (no. 201725. U. S. Natl. Mu.x., Bi- ological Survey collection). E. Citcllus bcldin(/i htltliii(/i. S ad., Mannuoth Pass, Calif, (no. 42025. U. S. Natl. Mus., Biological Survey collection). F. Citcllus avmatus. 6 ad., Barclay, Utah (no. 87791, U. S. Natl. Mu.>^., Bi- ological Survey collection). 237 Plate 24 (Natural size) A. Citcllus colunibknms coJumhianus, $ ad., Nelson, British Columbia (no. 66670, U. S. Natl. Mus., Biological Survey collection). B. Citellus parryii li/iatiis, S ad., St. Lawrence Island, Bering Sea (no. 57312, Mus. Vert. Zool.). C. Citellus osgoodi, S ad., Circle. Alaska (no. 128269, U. S. Natl. Mus., Bi- ological Survey collection). D. Citellus parryii t)lesius, S ad.. Head of Coal Creek, Yukon (no. 134954, U. S. Natl. Mus., Biological Survey collection). 238 North American Fauna No. 56. U. S. Dept. of Agriculture, Biological Survey Plate 24 SKULLS OF CITELLUS. North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey Plate 25 SKULLS OF CITELLUS. Plate 25 (Natural size) A. CifellKX spilosoDW npilosonxi. $ ad.. Chicalote. Agnasoalientes, Mexico (no. 78!t97, U. S. Natl. Mus., Biological Survey collection). B. Citellii-s spUosomn prattiisi.s, 3 sul)adult, Flagstaff, Ariz. (no. 202123, U. S. Natl. Miis., liioldgical Survey collection). C. CitcUiis mcrirdiitis m644. U. S. Natl. Mus., Biological Survey coll<>etion). 239 Plate 26 (Natural size) A. Citelhts ieecheiji parvidus, $ subadult. Loue Pine, Calif, (no. 32553, U. S. Natl. Mus., Biological Survey collection). B. Citelliis beechei/i douglasii, $ acL, Forest Grove, Oreg. (no. 30887, U. S. Natl. Mus., Biological Survey collection). C. Citellus varleyatus rupestris, 2 ad. (type), Rio Sestin. Durango (no. 21231, Amer. Mus. Nat. Hist.). D. Citellus cumulatus atnndatus, $ ad., Manzanillo, Colima. Mexico (no. 44596, U. S. Natl. Mus., Biological Survey collection). 240 North American Fauna No. 56. U. S. Dept. of Agriculture. Biological Survey Plate 25 SKULLS OF CITELLUS. North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey PLATE 27 SKULLS OF CITELLUS. F'late 27 (Natural size) A. CitcUiis lateralis mitratus, S ad., South YoUa Bolly Mountain, Calif, (no. 138124, U. S. Natl. Mus., Biological Survey collection). B. Citellus ntadrciisis, S ad., Sierra Madre. near Guadalupe y Calvo. Chihuahua. Mexico (no. 95357, U. S. Natl. Mus.. Biological Survey collection). C. Citellus tercticaiulus tcrcticaiidiis, $ ad.. Fort Yuma, Calif, (no. 99507, U. S. Natl. Mus., Biological Survey collection). D. Citellus lateralis lateralis, S ad., Hahn.s Peak. Colo. (no. 168865, U. S. Natl. Mu8., Biological Survey collection). E. Citellus adocefus, $ ad.," La Salada. Michoacan. Mexico (no. 126140, U. S. Natl. Mus., Biological Survey collection). F. Citellus leueurus leuvurns, $ ad., Caltazon. Calif, (no. 54010, U. S. Natl. Mus., Biological Survey collection). 241 Plate 28 (Natural size) A. CiteUiis toinisendii mollis, S ad., Fairfield, Utah, (uo. 30144, U. S. Natl. Mus., Biological Survey collection). B. Citellus, idalioeiisis, $ ad.. Nampa, Idaho (no. 168511, U. S. Natl. Mus., Biological Survey collection). C. Citellus icashiuytoni ivashiufftoni, $ ad., Wallula, Wash. (no. 235732, U. S. Natl.- i\Ius., Biological Survey collection). D. Citellus bruiiHeus, $ ad., Weiser, Idaho (no. 201725, U. S. Natl. Mus., Bi- ological Survey collection). E. Citellus heldiufii heldiiigi, $ ad.. Mammoth Pass, Calif, (no. 42025, U. S. Natl. Mus., Biological Survey collection). F. Citellus armatus, $ ad., Barclay, Utah (no. 87791, U. S. Natl. Mus., Biologi- cal Survey collection). 242 North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey PLATE 28 SKULLS OF CITELLUS. N orth American Fauna No. 56. U. S. Dept. of Agriculture, Biological Survey PLATE 29 SKULLS OF ClTELLUS. Plate 29 (Natural size) 4. Citellus columbianus coliiiiihiniiitx. $ ad.. Nelson. British Columbia (no. 66670, U. S. Natl. Mas., Biological Survey collection). B. Citellus parry a lyratiis, $ ad., St. Lawrence Island, Bering Sea (no. 57312, Mus. Vert. Zool.). C. Citellus osffoodi, S ad., Circle, Alaska ( no. 128369, U. S. Natl. Mus.. Biological Survey collection). D. Citellus parry a plesius, $ ad.. Head of Coal Creek. Yukon (no. 134954, U. S. Natl. Mus., Biological Survey collection). 243 Plate 30 (Natural size) A. CiteUiis spilosoma spilosoma, $ ad., Chicalote. Agiiascalientes, Mexico (no. 78997, U. S. Natl. Mus., Biological Survey collection). B. Citelltis spilosoma pratensis, S subadult, Flagstaff, Ariz. (no. 202123, U. S. Natl. Mus., Biological Survey collection). C. Citelltis mejcicanus mexicanus, S ad., Silao, Guanajuato, Mexico (no. 79108, U. S. Natl. Mus.. Biological Survey collection). D. Citellus perotensis, $ ad., Perote, Vera Cruz (no. 54265, U. S. Natl. Mus., Biological Survey collection). E. Citellus richardsonii elegans, S ad., Piuedale, Wyo. (no. 176905, U. S. Natl. Mus., Biological Survey collection). F. Citellus richardsonii richardsonii, $ ad., Wingard. Saskatchewan (no. 73644, U. S. Natl. Mus., Biological Survey collection). 244 North American Fauna No. 56. U. S. Dept. of Agriculture, Biological Survey Plate 30 A B c A . & D %^ ^ry A ■^"^1 ^ ^ -^ '■**' ^^^^^^H SKULLS OF CITELLUS. North American Fauna No. 56, U. S. Dept. of Agriculture, Biological Survey PLATE 3t SKULLS OF CITELLUS. Plate 31 (Natural size) A. Citc1lii.<< hecrhciii iKirnilii-s. £ subadiilt. Lone Pine. Calif, (no. 32o5?), U. S. Natl. Mn.s., Biological Survey collection). B. Citellus beech fiji doiiijlaaii, S ad., Forest Grove, Oreg. (no. 30S87, U. S. Natl. Mus., Biological Survey collection ) . C. Citellus rarief/otiix rupeHtriH, $ ad. (type), Rio Sestin. Durango (no. 21231, Amer. Mus. Nat. Hist.). D. Citellus animhitus aiiuiilatus. S ad., Manzanillo, Colinia. Mexico (no. 44-596, U. S. Natl. :Mus., Biological Survey collection). 245 Plate 32 (Natural size) A. Citellus lateralis mitratus, $ ad., South YoUa Bollv Mountain, Calif, (no. 138124, U. S. Natl. Mus., Biological Survey collection). B. Citellus madrensis, $ ad., Sierra Madre, near Guadalupe y Calvo, Chihuahua, Mexico (no. 95357, U. S. Natl. Mus., Biological Survey collection). C. Citellus tereticaudus tereticaudus, $ ad., Fort Yuma, Calif, (no. 99507, TJ. S. Natl. Mus., Biological Survey collection). D. Citellus lateralis lateralis, $ ad., Hahus Peak, Colo. (no. 168865, U. S. Natl. Mus., Biological Survey collection). E. Citellus adocctus, $ ad.. La Salada, Michoacan, Mexico (no. 126140, U. S. Natl. Mus., Biological Survey collection). F. Citellus leucurus leucurus, $ ad., Cabazon, Calif, (no. 54010, U. S. Natl. Mus., Biological Survey collection). 246 North American Fauna No. 56. U. S. Dept. of Agriculture, Biological Survey PLATE 32 SKULLS OF CITELLUS. INDEX [New names and principal page references to a species in boldface; synonyms in italic] aberti, Sciurus, 49, 50. ablusus, Citellus parrvii, 17, 54, 95, 97, 98, 100, 101, 102, 103. Citellus plesius, 98. Acknowledgments, 2. adocetus, Citellus, 29 (habits), 44, 164, 165. Otospermophilus, 165. adolphei, Sciurus, 49. aestuans, Sciurus, 50. albertae, Citellus columhianus, 85, 88. alfari, Microsciurus, 51. Sciurus, 51. alleni, Citellus tridecemlineatus, 113, 114, 115, 116, 117, 118. Sciurus, 50. Spermophilus tridecemlinentus, 114. Ainmospermophilus, 5, 29 (habits), 30, 35, 39, 44, 45, 53, 54, 166, 182. amplus, 182, 183. canfieldae, 178. cinnamomeus, 174. extimus, 179. harrisii, 167. insularis, 181. interpres, 180. kinoensis, 169. leucurus, 170. nelsoni, 182. peninsulae, 176. pennipes, 175. saxicola, 169. tersus, 173. amplus, Ammospermophilns nelsoni, 182, 183. Anisonyx, 53. brachinra, 53, 55, 85. canescens, 125. cinnamomeus, 174. cryptospilotus, 130. grammurus, 142. harrisii, 167. macros pilotus, 125. tereticaudus, 187. annectens, Citellus spilosoma, 128. S pernio philus spilosoma, 128. annulatuK, Citellus, 28 (habits), 29, 39, 46, 55, 162. Citellus annulatus, 163, 164, 165. Notocitellus, 46. Otospermophilus, 163. Spermophilus, 44, 55, 163. Antelope scjuirrel, 5, 29 (liabits), 35, 39, 54. Colorado, 175. Espiritu Santo, 181. Antelope squirrel — Continued. Grand Canyon, 173. gray-tailed, 167. mid-peninsular, 178. rusty, 174. San Joaquin, 182. southern peninsular, 179. Texas, 180. western peninsular, 176. white-tailed, 170. Yuma, 169. See also Ground squirrel. Rock squirrel. apache, Sciurus, 50. apricus, Citellus tereticaudus, 190. Araeosciurus, 50. Arctomys, 53, 55. beecheyi, 55, 148. brachyura, 85. brachyurus, 85. columbianns, 53, 55, 85. douglasii, 55, 150. erytkrogluteia, 55, 85, 88, 97. franklinii, 42, 133. hoodii, 55, 107. kennicottii, 55, 91, 94. lateralis, 191. parryi, 88, 91. phaeognatha, 55, 91. richardsonii, 73. tridecemlineata, 107. arenicola, Citellus tridecemlineatus, 111, 113, 116, 118. arens, Spermophilus spilosoma, 125. arizonae, Citellus tereticaudus, 187, 188. arizonensis, Callospermophilus lateralis^ 196. ■ Citellus lateralis, 191, 193, 196, 214. Sciurus, 50. armatus, Citellus, 10 (habits), 54, 78, 82, 83, 85. Spermophilus, 55, 56, 78. artemesiae, Citellus mollis, 63, 65. Citellus townsendii, 64, 65. asiaticus, Eutamias, 47. Sciurus striatus, 47. atricapillus, Citellus, 160, 161. Citellus variegatus, 161. Otospermophilus grammurus, 161. Spermophilus grammurus, 161. aureogaster, Sciurus, 49. badius, Ictidomys tridecemlineatus, 110. Spermophilus tridecemlineatus, 110, 111. Baiosciurus, 49. 247 248 NORTH AMERICAN FAUNA [No. 56 barrowensis, Citellus parryii, 94, 95, 99. Sper^nophilus, 95. beecheyi, Arctomys, 55, 148. Citellus, 5, 26, 43, 44, 133. Citellus beecheyi, 23 (habits), 28, 148, 151, 152, 153, 154, 155, 157, 158, 159, 160, 161, 162. Citellus grammurus, 148. Citellus variegatus, 148. Otospermophilus, 44, 148. Otospermophilus grammurus, 148. Spermophilus, 148. Spermophilus grammurus, 148. beldingi, Citellus, 40, 54, 81. Citellus beldingi, 11 (habits), 81, 83, 84. Spermophilus, 56, 81. bensoni, Citellus, 215. beringensis, Citellus parryii, 96. Spermophilus, 95. bernardinus, Callospermophilus, 209. Citellus chrysodeirus, 209. Citellus lateralis, 204, 209. Spermophilus, 209. boothiae, Sciurus, 49. boquetensis, Microsciurus, 51. hrachiura, Anisonyx, 53, 55, 85. hrachyura, Arctomys, 85. brachyurus, Arctomys, 85. brevicaudus, Spermophilus chrysodei- rus, 209. brochus, Syntheosciurus, 52. brunneus, Citellus, 71, 72. Citellus townsendii, 72. Bubonic plague, 10, 11, 13, 16, 26. buccatus, Sciurus, 136. buckleyi, Citellus variegatus, 43, 141, 144. Otospermophilus grammurus, 141. Spermophilus, 55, 141. Spermophilus grammurus, 141. buxtoni, Citellus, 3, 100, 102. Citellus parryii, 100. Callospermophilus, 5, 31 (habits), 35, 39, 45, 53, 54, 190, 215. arizonensis, 196. bernardinus, 209. caryi, 197. castanurus, 201. certus, 208. chrysodeirus, 203, 215, 216. cinerascens, 198, 199. connectens, 205. lateralis, 43, 192. madrensis, 213. mitratus, 210. perpallidus, 206, 207. saturatus, 212. tescorum, 199. trepidus, 206. trinitatis, 211. wortmani, 195. canescens, Anisonyx, 125. Citellus spilosoma, 124, 125, 126, 129. Spermophilus, 125. Xerospermophilus, 125. canfieldae, Ammospermophilus leucurus, 178. Citellus leucurus, 177, 178, 179. canus, Citellus mollis, 67. Citellus townsendii, 61, 64, 66, 67, 71. Spermophilus mollis, 67. captus, Citellus beecheyi, 216. carolinensis, Neosciurus, 51. Sciurus, 48, 49, 50, 51. caryi, Callospermophilus lateralis, 197. Citellus lateraUs, 193, 195, 197, 202. castanurus, Callospermophilus, 201. Citellus, 201. Citellus lateralis, 192, 193, 197, 198, 199, 201, 203, 205, 207. Spermophilus, 201. Tamias, 201. certus, Callospermophilus lateralis, 208. Citellus laterahs, 204, 208. Chickaree, 51. Chipmunk, 35, 52. eastern, 46, 47. western, 47. chlorus, Citellus, 188. Citellus tereticaudus, 188. chrysodeirus, Callospermophilus, 203, 215, 216. Citellus, 203, 215, 216. Citellus lateralis, 194, 198, 203, 205, 207, 208, 209, 210, 211, 212, 213. Spermophilus, 203. Tamias, 203. cinerascens, Callospermophilus, 198, 199. Citellus, 198, 199. Citellus laterahs, 192. 197. 198. 190. 200, 201, 202. Spermophilus, 198. Tamias, 198. Tamias lateralis, 198. cinereicollis, Eutamias, 48. cinnamomeus, Amm,ospermophilus leu- curus, 174. Anisonyx leucurus, 174. Citellus leucurus, 167, 168, 171, 172, 173, 174, 175, 176, 180, 181, 182. Spermophilus leucurus, 174 Tamias leucurus, 174. citellus, Citellus, 2, 40, 54. Mus, 39, 40, 53. Citellus, 39 (genus), 40 (subgenus). ablusus, 17, 54, 95, 97, 98, 100, 101, 102, 103. adocetus, 29 (habits), 44, 164, 165. albertae, 85, 88. alleni, 113, 114, 115, 116, 117, 118. annectens, 128. annulatus, 28 (habits), 29, 39, 46. 55, 162, 163, 164, 165. apricus, 190. arenicola, 111, 113, 116, 118. arizonae, 187, 188. arizonensis, 191, 193, 196, 214. armatus, 10 (habits), 54, 78, 82, 83, 85. artemesiae, 63, 64, 65. atricapillus, 160, 161. barrowensis, 94, 95, 99. 1938] REVISION OF THE GROUND SQUIRRELS 249 Citellus — Continued. beecheyi, 5, 23 (habits), 26, 28, 43, 44, 133, 148, 151, 152, 153, 154, 155, 157, 158, 159, 160, 161, 162. beldingi, 11 (habits), 40, 54, 81, 83, 84. bensoni, 215. beringensis, 96. bernardinus, 204, 209. brunneus, 71, 72. bucklevi, 43, 141, 144. buxtoni, 3, 100, 102. canescens, 124, 125, 126, 129. canfieldae, 177, 178, 179. canus, 61, 64, 66, 67, 71. captus, 216. carvi, 193, 195, 197, 202. castanurus, 192, 193, 197, 198, 199, 201, 203, 205, 207. certus, 204, 208, chlorus, 188. chrvsodeirus, 194, 198, 203, 205, 207, 208, 209, 210, 211, 212, 213, 215, 216. cinerascens, 192, 197, 198, 199, 200, 201, 202. cinnamomeus, 167, 168, 171, 172, 173, 174, 175, 176, 180, 181, 182. citellus, 2, 40, 54. cochisei, 215. columbianus, 5, 13 (habits), 54, 85, 89, 90, 98. connectens, 201, 205. couchi, 140. couchii, 137, 138, 139, 141, 143. cryptospilotus, 129, 130. douglasi, 150. douglasii, 27 (habits), 148, 150, 155, 216. elegans, 5, 10 (habits), 11, 68, 74, 75, 76, 77, 79, 80, 81, 82, 83, 132. eremonomus, 185, 186. erythrogluteius, 97, 98. eversmanni, 54. extimus, 177, 178, 179, 181. fisheri, 28, 150, 151, 152, 153, 154, 156, 157, 158, 216. franklini, 133. franklinii, 3, 5, 21 (habits), 41, 42, 43, 44, 133, 215. fulvus, 54. goldmani, 164. grammurus, 23, 43, 45, 55, 137, 139, 140, 141, 142, 146, 147, 148. guttatus, 71. harrisi, 167. harrisii, 167, 170, 171, 172. hollisteri, 115, 117. idahoensis, 6 (habits), 54, 63, 68, 69, 72. insularis, 164, 181. interpres, 169, 176, 180. juglans, 142, 144. kadiacensis, 103. kennicotti, 91. kennicottii, 91. Citellus — Continued. kodiacensis, 97, 99, 100, 103. laterahs, 43, 55, 191, 195, 196, 197, 198, 201, 202, 203, 212, 213, 214. leucurus, 168, 169, 170, 173, 174, 175, 176, 177, 178, 179, 180, 182. leurodon, 63, 64. loringi, 71. lyratus, 97, 99, 101, 103. macrospilotus, 125. madrensis, 46, 191, 213. major, 126, 128, 129, 130, 131. mexicanus, 5, 20 (habits), 41, 42,43, 54, 119, 121, 122,215, 216. microspilotiis, 125. mitratus, 204, 210, 212. mohavensis, 30 (habits), 183, 185. mollis, 5, 6, 7, 45, 54, 63, 65, 66, 67, 68, 72, 106, 183, 184, 185, 186. monticola, 116, 118. nebulicola, 100, 102. neglectus, 186, 187. nelsoni, 182. nesioticus, 160. nevadensis, 77, 79. nudipes, 150, 157, 158, 160. obsoletus, 127, 130. oregonus, 5, 12 (habits), 41, 43, 77, 79 80 82 83. osgoodi', 17 (habits), 54, 92, 98, 104. pallescens, 124, 125, 126, 132. pallidus, 109, 111, 112, 115, 118. parry i, 91. parrvii, 3, 16 (habits), 38, 39, 54, 5o, 90, 91, 95, 96, 97, 98, 99, 100, 104, 105, 136. parvidens, 119, 121. parvulus, 150, 155, 156, 158, 159, 160. parvus. 113, 115, 117. peninsulae, 166, 176, 178, 179. pennipes, 175. perotensis, 21, 41, 42, 132. pessitnus, 65. plesius, 16, 17, 86, 87, 88, 92, 97, 99, 100, 105, 133. pratensis, 128, 130. quatalensis, 214, 215. richardsoni, 73. richardsonii, 5, 8 (habits), 54, 73, 76, 77, 78, 79, 81, 85, 86. ridgwayi, 215. ruficaudus, 88, 89. rupestris, 137, 138, 140, 141, 144. rupinaruni, 159. saturatus, 191, 203, 212. saxicola, 169. sierrae, 153, 155. spilosoma, 5, 20 (habits), 31, 41, 42, 55, 70, 120, 122, 124, 126, 131, 132. stejnegeri, 3. slonei, 98, 100. taylori, 216. tereticaudus, 30 (habits), 41, 45, 184, 185, 187, 189, 190. 250 NORTH AMERICAN FAUNA [No. 56 Citellus — Continued. tersus, 173. tescoriim, 198, 199, 206, 212, 213. texensis, 107, 109, 110, 111, 122. townsendi, 216. townsendii, 5 (habits), 55, 60, 69, 70 71 73 trepi'dus,' 201, 202, 204, 206, 208. tridecemlineatus, 3, 5, 18 (habits), 21, 31, 41, 42, 54, 106, 107, 110, 113, 115, 118, 119, 216. trinitatis, 210, 211. tuitus, 215. tularosae, 145. Utah, 144, 146. variegatus, 22 (habits), 54, 55, 136, 138, 140, 146. vigilis, 61, 66, 67, 68. vinnulus, 170. vociferans, 185, 186. Washington!, 5, 6, 7 (habits), 54, 62, 63, 69, 71, 72, 73, 106, 107, 216. washoensis, 63, 64. wortmani, 191, 193, 195. yakimensis, 60, 63. Citillus, 53. mexicanus, 119. citillus, Mus, 53. cochisei, Citellus, 215. coUiaei, Sciurus, 49. Colobates, 53. Colobotis, 53, 54. columbianus, 85. franklinii, 54. hoodii, 54. kennicotti, 91. parry i, 91. richardsonii, 54. tridecemlineatus, 54. Colored plates, explanation of, 2. columbianus, Arctomys, 53, 55, 85. Citellus, 5, 13 (habits), 54, 85, 98. Citellus columbianus, 85, 89, 90. Colobotis, 85. Spermophilus, 85. concolor, Sciurus, 50. connectens, Callospermophilus chryso- deirus, 205. Citellus lateralis, 201, 205. couchi, Citellus variegatus, 140. couchii, Citellus variegatus, 137, 138, 139, 141, 143. Otospermophilus, grammurus, 140. Spermophilus, 55, 139. Spermophilus grammurus, 139. Cranial measurements, explanation of, 59. cryptospilotus, Anisonyx, 130. Citellus spilosoma, 129, 130. Spermophilus, 130. Xerospermophilus, 130. Cynomys, 35, 38, 39. gunnisoni, 55, 88. ludovicianus, 38. socialis, 38. deppei, Sciurus, 49. Diseases — Bubonic plague, 10, 11, 13, 16, 26. Rocky Mountain spotted fever, 16. Tularemia, 6, 26, 27. dorsalis, Eutamias, 48. douglasi, Citellus beecheyi, 150. Citellus variegatus, 150. douglasii, Arctomys, 55, 150. Citellus, 216. Citellus beecheyi, 27 (habits), 148, 150, 155. Otospermophilus grammurus, 151. Spermophilus, 150. douglassi, Spermophilus grammurus, 150. durangi, Sciurus, 50. Echinosciurus, 48, 49. elegans, Citellus, 10, 11, 76. Citellus richardsonii, 5, 10 (habits), 68, 74, 75, 76, 77, 79, 80, 81, 82- 83, 132. Spermophilus, 55, 56, 62, 76. Spermophilus richardsoni, 76. empetra, Mus, 91. Spermophilus, 56, 91. eremonomus, Citellus, 185, 186. erythroglutaeus, Spermophilus empetra, 85. erythrogluteia, Arctomys, 55. Arctomys parryi, 85, 88, 97. Spermophilus parryi, 85. erythrogluteius, Citellus, 97, 98. Eutamias, 35, 39, 44, 46, 47, 52. asiaticus, 47. cinereicollis, 48. dorsalis, 48. frater, 48. sonomae, 48. eversmanni, Citellus, 54. Spermophilus, 53. extimus, Ammospermophilus leucurus, 179. Citellus leucurus, 177, 178, 179, 181. Fever, Rocky Mountain spotted, 16. fisheri, Citellus beecheyi, 28, 150, 151, 152, 153, 154, 156, 157, 158, 216. Citellus variegatus, 154. Otospermophilus grammurus, 154. Spermophilus beecheyi, 154. Spermophilus grammurus, 154. Flying squirrel, 35, 52. Fossil species, 214. Fox squirrel, 34, 50. franklini, Spermophilus, 133. franklinii, Arctomys, 42, 133. Citellus, 3, 5, 21 (habits), 41, 42, 43, 44, 133, 215. Colobotis, 54. Poliocitellus, 43, 44. Spermophilus, 133. frater, Eutamias quadrivittatus, 48. 1938] REVISION OF THE GROUND SQUIRRELS 251 fulvus, Citellus, 54. Spermophilus, 53, 54. Geographic distribution, 2. gerrardi, Sciurus, 51. gidleyi, Otospermophilus, 215. Glaucomys, 35, 52. goldmani, Citellus annulatus, 164. Otospermophilus annulatus, 164. Sciurus, 49. Spermophilus annulatus, 164. grammurus, Anisonyx, 142. Citellus, 43, 45, 55. Citellus grammurus, 142. Citellus variegatus, 23, 43, 137, 139, 140, 141, 142, 146, 147, 148. Otospermophilus, 142. Otospermophilus grammurus, 142. Sciurus, 43, 53, 142. Spermophilus grammurus, 142. Gray gopher, 21. Gray squirrel, eastern, 34. western, 34. griseoflavus, Sciurus, 49. griseus, Sciurus, 49, 50. Ground hog, 37. Ground squirrel, Aleutian, 98. antelope, 5, 29 (habits), 54. Apache spotted, 125. Arizona mantled, 196. Arizona round-tailed, 187. Arizona striped, 116. Barrow, 95. Belding's, 11 (habits), 81. Bennett's spotted, 122. Bighorn striped, 114. Blue Mountains, 89. Blue Mountains mantled, 205. California, 4, 5, 23 (habits), 148. Gary's mantled, 197. Cascade mantled, 212. Catalina, 160. Catavina, 159. Charleston Mountains mantled, 208. Columbian, 4, 5, 13 (habits), 55, 85. desert spotted, 130. Douglas's, 5, 27 (habits), 150. Fisher's, 154. Franklin's, 5, 21 (habits), 39, 55, 133. golden-mantled, 203. Goldman's, 28 (habits), 164. gray, 3, 67. Hoilister's mantled, 199. HoUister's striped, 115. Idaho spotted, 72. Jaurez, 158. Kennicott's spotted, 130. Kodiak, 103. least Idaho, 65. least striped, 117. lesser California, 156. lesser tropical, 29 (habits), 165. Ground squirrel — -Continued. Loring's, 71. Malheur Vallev, 66. mantled, 5, 31 (habits), 35, 39, 54. Merriam's mantled, 198. Mexican, 20 (habits), 119. Mexican spotted, 55. Mohave, 30 (habits), 183. Nevada, 77. Nevada mantled, 206. New Mexico spotted, 126. Oregon, 4, 5, 12 (habits), 83. Padre Island, 128. pallid spotted, 124. pallid striped, 112. Palm Springs, 188. park spotted, 128. Parrv's, 16 (habits), 88, 91. Perote, 21, 132. Piute, 63. Richardson's, 4, 5, 8 (habits), 55, 73. ring-tailed, 28 (habits), 39, 163. Rio Grande. 121. round-tailed, 5, 30 (habits), 185. St. Lawrence Island, 101. San Bernardino mantled, 209. sandhill striped, 111. Say's mantled, 191. Shumagin, 100. Sierra, 153. Sierra Madre mantled, 213. Snake Vallev, 6 (habits), 68. spotted, 5, 20 (halnts), 39. striped, 5, 18 (habits), 39, 55. Texas striped. 110. thirteen-lined, 107. Townsend's, 5 (habits), 60. Trinidad Valley, 190. Trinitv Mountains mantled, 211. Uinta,' 4, 10 (habits), 78. Wasatch mantled, 201. Washington, 5, 7 (habits), 69. Wortman's mantled, 195. Wvoming, 5, 10 (habits), 76. Yolla Bolly mantled, 210. Yukon, 97. Yukon Valley, 17 (habits), 104. See also Antelope squirrel, Rock squirrel. Gucrlinguetus, 50. guerlinguetus, Sciurus, 50. gunnisoni, Cynomys, 55, 88. Spermophilus, 38. guttatus, Citellus, 71. Spermophilus, 62. Habits and economic relations, 4. harrisi, Citellus, 167. Tamias, 167, 170. harrisii, Ammospermophilus, 167. Anisonyx, 167. Citellus harrisii, 167, 170, 171, 172. Spermophilus, 55, 56, 167, 170. Hesperosciurus, 34, 49. 252 NORTH AMERICAN FAUNA [No. 56 hoffmanni, Sciurus, 51. hoUisteri, Citellus tridecemlineatus, 115, 117. hoodii, Arctomys, 55, 107. Colobotis, 54. hudsonicus, Sciurus, 51. Tamiasciurus, 50. hypopyrrhus, Sciurus aureogaster, 48, 49. Ictidomoides, 41, 53, 54. Ictidomys, 39, 41, 42, 53, 54, 106, 215, 216. badius, 110. mexicanus, 43. tereticaudus, 187. idahoensis, Citellus, 6 (habits), 54, 63, 68, 69, 72. insularis, Ammospermophilus leucurus, 181. Citellus, 164, 181. Citellus leucurus, 181. nterpres, Ammospermophilus, 180. Ammospermophilus leucurus, 180. Citellus, 169, 176, 180. Spermophilus, 180. Tamias, 180. isthmius, Microsciurus, 51. juglans, Citellus variegatus, 142, 144. kadiacensis, Citellus parry i, 103. kaibabensis, Sciurus, 50. kennicotti, Citellus parryi, 91. Colobotis parryi, 91. kennicottii, Arctomys, 55, 91, 94. Citellus parryi, 91. Keys — Ammospermophilus, 167. Callospermophilus, 191. Citellus, 56, 59. Ictidomys, 106. Notocitellus, 162. Otospermophilus, 135. Sciuridae, 36. Xerospermophilus, 183. kinoensis, Ammospermophilus harrisii, 169. kodiacensis, Citellus, 97, 99, 100, 103. Spermophilus empetra, 103. Spermophilus parryi, 103. Spermophilus parryii, 56. lateralis, Arctomys, 191. Callospermophilus, 43, 192. Citellus, 43, 55, 192. Citellus laterahs, 191, 195, 196, 197, 198, 201, 202, 203, 212, 213, 214. Sciurus, 45, 53, 191. Spermophilus, 56, 191. Tamias, 192. Leucocrossuromys, 38. leucurus, Ammospermophilus, 170. Citellus leucurus, 168, 169, 170, 173, 174, 175, 176, 177, 178, 179, 180, 182. Spermophilus, 53, 54, 170. Tamias, 44, 170. leurodon, Citellus, 63, 64. loringi, Citellus Washington!, 71. ludovicianus, Cynomys, 38. lyratus, Citellus, 101. Citellus parryii, 97, 99, 101, 103. macrospilotus, Anisonyx spilosoina, 125. Citellus spilosoma, 125. Spermophilus spilosoma, 125. Xerospermophilus spilosoma, 125. macrourus, Spermophilus, 55, 136. madrensis, Callospermophilus, 213. Citellus, 46, 191, 213. major, Citellus spilosoma, 126, 128, 129, 130, 131. Spermophilus spilosoma, 126. managuensis, Sciurus, 49. marginatus, Spermophilus spilosoma,12Gf 127. Marmot, 35, 36, 37, 38. Marmota, 35, 37, 38, 53. marmota, 38. monax, 38. marmota, Marmota, 38. Mus, 37. Marmotops, 38. merriami, Tamias asiaticus, 47. Mesosciurus, 50. mexicanus, Citellus, 5, 20, 41, 42, 43, 54. 215, 216. Citellus mexicanus, 119, 121, 122. Citillus, 119. Ictidomys, 43. Otospermophilus, 119. Sciurus, 41, 53, 119. Spermophilus, 119. Microsciurus, 35, 51, 52. alfari, 51. boquetensis, 51. isthmius, 51. septentrionalis, 51. microspilotus , Citellus spilosoma, 125. Spermophilus spilosoma, 125. mitratus, Callospermophilus chryso- deirus, 210. Citellus lateralis, 204, 210, 212. mohavensis, Citellus, 30 (habits), 183, 185, 186. Citellus tereticaudus, 183, 185. Spermophilus, 45, 53, 54, 183. mollis, Citellus, 5. Citellus townsendii, 6, 7, 45, 54, 63, 65, 66, 67, 68, 72, 106, 183, 184, 185, 186. Spermophilus, 55, 62, 63. Spermophilus townsendi, 63. monax, Marmota, 38. monticola, Citellus tridecemlineatus, 116, 118. Mus citellus, 39, 40, 53. citillus, 53. empetra, 91. marmota, 37. volans, 52. nayaritensis, Sciurus, 50. nebulicola, Citellus, 100. Citellus parryii, 100, 102. 19381 REVISION OF THE GROUND SQUIRRELS 253 neglectus, Citellus, 187. Citellus tereticaudus, 186, 187. Spermophilus, 187. nelsoni, Ammospermophilus, 182. CiteUus, 182. Sciurus, 49. Spermophilus, 182. Neosciurus, 34, 48, 50. carolinensis, 51. Neotamias, 47. nesioticus, Citellus, 160. Citellus beecheyi, 160. Otospermophilus, 160. nevadensis, CiteUus elegans, 77. CiteUus richardsonii, 77, 79. niger, Sciurus, 50. Notocitellus, 39, 44, 45, 162. annulatus, 46. nudipes, Citellus beecheyi, 150, 157, 158, 160. obsidianus, Spermophilus spilosoma, 128. obsoletus, Citellus, 130. CiteUus spnosoma,127, 130. Spermophilus, 55, 130. oculatus, Sciurus, 50. olivaceus, Spermophilus tridecemlineatus, 112, 113. oregoDUS, Citellus, 83. Citellus beldingi, 5, 12 (habits), 41, 43, 77, 79, 80, 82, 83. Spermophilus, 83. osgoodi, CiteUus, 17 (habits), 54, 92, 98, 104. Spermophilus, 104. Otocolobus, 53. Otosciurus, 34, 50. Otospermophilus, 5, 35, 39, 42, 43, 45, 48, 53, 135, 164, 215. adocetus, 165. annulatus, 163. atricapiUus, 161. beecheyi, 44, 148. buckleyi, 141. couchii, 140. douglasii, 151. fisheri, 154. gidleyi, 215. goldmani, 164. grammurus, 142. mexicanus, 119. nesioticus, 160. rupestris, 138. tularosae, 145. Utah, 146. variegatus, 136. pallescens, CiteUus spilosoma, 124, 125, 126, 132. pallidus, CiteUus tridecemlineatus, 109, 111, 112, 115, 118. Spermophilus tridecemlineatus, 56, 112. Parasciurus, 34, 50, 51. parryi, Arclomys, 88. Citellus, 91. Colobotis, 91. Spermophilus, 91. parryii, Arctomys, 91, Citellus, 3, 38, 39, 54, 55, 90, 136. CiteUus parryii, 16 (habits), 91, 95, 96, 97, 98, 99, 100, 104, 105. Spermophilus, 91. parvidens, Citellus mexicanus, 119, 121. Spermophilus mexicanus, 121. parvulus, Citellus beecheyi, 150, 155, 156, 158, 159, 160. parvus, CiteUus tridecemlineatus, 113, 115, 117. Citellus tridecimlineatus, 117. Spermophilus tridecemlineatus, 117. peninsulae, Ammospermophilus leucu- rus, 176. Citellus leucurus, 166, 176, 178, 179. Tamias leucurus, 176. pennipes, Ammospernaophilus leucurus, 175. Citellus leucurus, 175. perotensis, CiteUus, 21, 41, 42, 132. Spermophilus, 132. perpallidus, Callospermophilus chryso- deirus, 206, 207. pessimus, Citellus mollus, 65. phaeognatha, Arctomys, 55. Arctomys parryi, 91. Plague, bubonic, 10, 11, 13, 16, 26. plesius, CiteUus, 97. Citellus parryii, 16, 17, 86, 87, 88, 92, 97, 99, 100, 105, 133. Spermophilus, 17, 18. Spermophilus empetra, 97. Pocket gopher, 11. Poliocitellus, 39, 42, 133. franklinii, 43, 44. poliopus, Sciurus, 49. Prairie dog, 35, 36, 38, 55, 88. pratensis, Citellus spilosoma, 128, 130. Spermophilus spilosoma, 128. Protospermophilus quatalensis, 214, 215. Pygmy squirrel, 51, 52. quatalensis, Citellus, 214, 215. Protospermophilus, 214, 215. Red squirrel, 51. richardsoni, Citellus, 73. Spermophilus, 62. richardsonii, Arctomys, 73. CiteUus, 54, 85. Citellus richardsonii, 5, 8 (habits') 73, 76, 77, 78, 79, 81, 86. Colobotis, 54. Spermophilus, 56, 73. richmondi, Sciurus, 51. ridgwayi, Citellus, 215. Rock squirrel, 5, 22 (habits), 35, 39, 43, 53. black-backed, 141. brown-headed, 138. Couch's, 139. Lower California, 161. Malpais, 145. Mexican, 55, 136. Say's, 23, 142. Utah, 4, 146. See also Antelope squirrel, Ground squirrel. 254 NORTH AMERICAN FAUNA [No. 66 Rocky Mountain spotted fever, 16. ruficaudus, Citellus columbianus, 88, 89. rupestris, Citellus grammurus, 138. Citellus variegatus, 137, 138, 140, 141, 144. Otospermophilus grammurus, 138. rupinarum, Citellus beecheyi, 159. saturatus, Callospermophilus lateralis, 212. Citellus, 191, 203, 212. Citellus lateralis, 212. Spermophilus lateralis, 212, Tamias lateralis, 212. saxicola, Ammospermophilus harrisii, 169. Citellus harrisi, 169. Citellus harrisii, 169. Spermophilus harrisi, 169. saxicolus, Spermophilus harrisii, 169. Sciuridae, classification, 34. Sciurus, 34, 35, 48. aberti, 49, 50. adolphei, 49. aestuans, 50. alfari, 51. alleni, 50. apache, 50. arizonensis, 50. asiaticus, 47. aureogaster, 49. boothiae, 49. buccaius, 136. carolinensis, 48, 49, 50, 51, coUiaei, 49. concolor, 50. deppei, 49. durangi, 50, gerrardi, 51. goldmani, 49. grammurus, 43, 53, 142. griseoiiavus, 49, griseus, 49, 50. guerlinguetus, 50. hoffmanni, 51. hudsonicus, 51. hypopyrrhus, 48, 49. kaibabensis, 50, lateralis, 45, 53, 191. managuensis, 49, mexicanus, 41, 53, 119. nayaritensis, 50. nelsoni, 49. niger, 50. oculatus, 50. poliopus, 49. richmondi, 51. sinaloensis, 49. socialis, 49, striatus, 46. thomasi, 49. tridecemlineatus, 41, 53, 55, 107. truei, 49, variegatoides, 49. variegatus, 136, 137. vulgaris, 48, 49, 50. yucatanensis, 49. septentrionalis, Microsciurus, 51. Seton, Ernest Thompson, 2. sierrae, Citellus beecheyi, 153, 155. sinaloensis, Sciurus, 49. socialis, Cynomys, 38. Sciurus, 49. sonomae, Eutamias townsendii, 48. sonoriensis, Spermophilus, 187, 188. Spermatophilus, 53. Spermophila,- 53. Spermophiie, eared, 43. Parry's, 55, 56. round-tailed, 55. Spermophilis, 53. Spermophillus, 53. Spermophilus, 53. alleni, 114. annectens, 128. annulatus, 44, 55, 16b. arens, 125. armatus, 55, 56, 78. atricapillus, 161. hadius, 110, 111, harrowensis, 95, beecheyi, 148. beldingi, 56, 81. beringensi$, 95. bernardinus, 209, brevicaudus, 209. buckleyi, 55, 141, canescens, 125, canus, 67, castanurus, 201. chrysodeirus, 203. cinerascens, 198. cinnamomeus, 174. columbianus, 85. concha, 55, 139. cryptospilotus, 130, douglasii, 150, douglassi, 150. elegans, 55, 56, 62, 76. em,petra, 56, 91. erythroglutaeus, 85, erythrogluteia. 85, eversmanni, 53. fisheri, 154, franklini, 133. franklinii, 133. fulvus, 53, 54. goldmani, 164. grammurus, 142. gunnisoniy 38. guttatus, 62. harrisii, 55, 56, 167, 170. interpres, 180. kodiacensis, 56, 103. lateralis, 56, 191. leucurus, 53, 54, 170. macrospilotus, 125. macrourus, 55, 136. major, 126, marginatus, 126, 127. mexicanus, 119. microspilotus, 125. mohavensis, 45, 53, 54, 183. mollis, 55, 62, 63, neglectus, 187. nelsoni, 182, obsidianus, 128, 1938] REVISION OF THE GROUND SQUIRRELS 255 Spermophilus — Continued. obsoletus, 55, 130. olivaceus, 112, 113. oregonus, 83. osgoodi, 104. pallidus, 56, 112. parryi, 91. parryii, 91. parvidens, 121. parvus, 117. peroiensis, 132. plesius, 17, 18, 97. pratensis, 128. richardsoni, 62. richardsonii, 56, 73. saturatus, 212. saxicola, 169. saxicolus, 169. sonoriensis, 187, 188. spilosomd, 122. stephensi, 63, 64. tereticaudus, 55, 185. texensis, 110. townsendi, 65, 76. fownsendii, 56, 60, 69, 76. tridecemlineatus, 107. variegatus, 136. wortmani, 195. yakimensis, 60. spilosoma, Citellus, 5, 20 (habits), 31, 41, 42, 55, 70, 120. Citellus spilosoma, 122, 124, 126, 131, 132. Spermophilus, 122. Squirrel, Abert's, 34. flying, 35, 52. fox, 34, 50. gray, 34. pygmy, 51, 52. red, 51. tree, 34, 35, 36, 39, 42, 48, 164. (See aZso Antelope squirrel. Ground squirrel, Rock squirrel, stejnegeri, Citellus, 3. stephensi, Spermophilus mollis, 63, 64. stonei, Citellus, 98, 100. striatus, Tamias, 46. Sciurus, 46. Syntheosciurus, 35, 52. brochus, 52. Tamias, 35, 46, 47, 56. chrysodeirus, 203. castanurus, 201. cinerascens, 198. cinnamomeus, 174. harrisi, 167, 170. inierpres, 180. lateralis, 192. leucurus, 44, 170. merriami, 47. peninsulae, 176. saturatus, 212. striatus, 46. wortmani, 195. Tamiasciurus, 34, 35, 51. hudsonicus, 50. taylori, Citellus, 216. tereticaudus, Anisonyx, 187. Citellus, 30 (habits), 41, 45, 184. Citellus tereticaudus, 185, 187, 189, 190. Ictidomys, 187. Spermophilus, 55, 185. tersus, Ammospermophilus leucurus, 173. Citellus leucurus, 173. tescorum, Callospermophilus lateralis, 199. Citellus lateralis, 198, 199, 206, 212, 213. texensis, CiteUus tridecemlineatus, 107, 109,110,111,122. Spermophilus tridecemlineatus, 110. thomasi, Sciurus, 49. Thomomys, 11. Thompson, Ernest E., 2. townsendi, Citellus, 216. Spermophilus, 65. Spermophilus richardsoni, 76. townsendii, Citellus, 5 (habits), 55, 69, 73. Citellus to^\Tisendii, 5, 60, 70, 71. Spermophilus, 56, 60, 69, 76. trepidus, Callospermophilus, 206. CiteUus, 206. CiteUus lateraUs, 201, 202, 204, 206, 208. tridecemlineata, Arctomys, 107. tridecemlineatus, Citellus, 3, 5, 18 (habits), 21, 31, 41, 42, 54, 106, 118, 216. Citellus tridecemlineatus, 107, 110, 113, 115, 119. Colobotis, 54. Sciurus, 41, 53, 55, 107. Spermophilus, 107. tridecimlineatus, Citellus, 107. trinitatis, Callospermophilus chryso- deirus, 211. Citellus chrysodeirus, 211. Citellus lateralis, 210, 211. truei, Sciurus, 49. tuitus, CiteUus, 215. Tularemia, 6, 26, 27. tularosae, Citellus grammurus, 145. Citellus variegatus, 145. Otospermophilus grammurus, 145. Type localities, list of, 56. Urocitellus, 53. Utah, Citellus grammurus, 146. Citellus variegatus, 144, 146. Otospermophilus grammurus, 146. variegatoides, Sciurus, 49. variegatus, CiteUus, 22 (habits), 54, 55, 136. CiteUus variegatus, 22, 136, 138, 140, 146. Otospermophilus, 136. Sciurus, 136, 137. Spermophilus, 136. vigilis, Citellus canus, 66. Citellus mollis, 66. CiteUus townsendii, 61, 66, 67, 68. 256 NORTH AMERICAN FAUNA vinnulus, Citellus leucurus, 170. vociferans, Citellus tereiicaudus, 185, 186. volans, Mus, 52, vulgaris, Sciurus, 48, 49, 50. Washington!, Citellus, 5, 6, 7, (habits), 54, 62, 73, 216. Citellus Washington!, 63, 69, 71, 72, 106, 107. washoensis, Citellus mollis, 63, 64. Woodchuck, 37. wortmani, CaUospermophilus, 195. Callospermophilus lateralis, 195. CiteUus, 195. CiteUus lateralis, 191, 193, 195. wortmani — Continued. Spermophilus, 195. Tamias, 195. 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Revision ot t-he North Americ an Ground Squirrels, with a Classification of the North American Sciurldae. By Abthub H. Howxix. Pp. 256, pis. 32, flgs. 20, 1938. Price 40 cents. UNITED STATES DEPARTMENT OF THE INTERIOR 'Harold L. Ickes, Secretary FISH AND WILDLIFE SERVICE Ira N. Gabrielson, Director North American Fauna 57 ATTWATER'S PRAIRIE CHICKEN ITS LIFE HISTORY AND MANAGEMENT BY VALGENE W. LEHMANN UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON : 1941 For sale by the Superintendent of Documents, Washington, D. C. - - • - Price 40 cents i ir' ABSTRACT ATTWATER'S PRAIRIE CHICKEN, a characteristic bird of the Texas coastal prairie, is closely related to the now extinct heath-hen of northeastern North America. Once abundant in an area extending from the coastal tall -grass prairies of southwestern Louisiana and Texas west and south to near Port Isabel, it has decreased in numbers as man has exploited its habitat, until now it is threatened ^vith the same fate as that of the heath-hen. Important factors limiting the numbers of the bird include excessive or persistent rainfall dm-ing the nesting season, heavy grazing, excessive pasture burning, agricultvu^al operations, and overshooting. Management will usually involve protection from excessive kiUing, improvement of food and cover, and control of predators and of the kill by hunters. Responsibility for this rests with the landowTier. Optimum prairie chicken range apparently consists of well-drained grass- land, with some weeds or shrubs, the cover varying in density from light to heavy; and with surface water available in summer; diversification within the grassland type is essential. In the absence of ample refuges for the species, probably all other favorable factors together will fail to save Attwater's prairie chicken from extinction. This number continues the series of the North American Fauna issued by the Bureau of Biological Survey, of the United States Department of Agri- culture, prior to its transfer and consolidation with the Bureau of Fisheries on June 30, 1940, to form the Fish and Wildlife Service, in the Department of the Interior. CONTENTS Page Introduction 1 Former distribution of prairie chickens in Texas 2 Differences between Attwater's and the other prairie chickens 4 Attwater's prairie chicken 4 Lesser prairie chicken 5 Former abundance of Attwater's prairie chickens 6 Present distribution and numbers 7 Habits 10 Courtship and mating 10 Nesting 14 Growth and development of young 16 Brood size 18 Juvenile mortality 19 Family disintegration 19 Annual increase 20 Flocking 20 Seasonal movements 21 Spring 21 Summer 22 Fall and winter 24 Food 25 Habitat requirements 30 Kind of environment best suited 30 Character and density of vegetation 30 Topography 30 Water 31 Seasons of scarcity 31 Limiting factors 31 Natural factors 32 Rainfall during the nesting season _■ 32 Floods 35 Drought 35 Hurricanes 35 Hail 35 Local storms 36 Disease 36 Spread of woody vegetation 36 Predation 37 Nests 37 Young 38 Adults 39 Review of natural factors 40 Artificial factors 40 Agriculture 40 Pasture burning 41 rn IV CONTENTS Limiting factors — Continued. Artificial factors— Continued. Page Overgrazing 42 Oil development 43 Drainage 43 Pasture mowing _ 43 Mechanical accidents 44 Hunting 44 Management 45 Protection 45 Habitat improvement 46 Evaluating conditions 47 Census methods 47 Spring counts on the courtship grounds 47 Rope count 49 Car-dog count 52 Using the census 52 Spring 53 Summer 54 Winter 55 General recommendations for habitat control 56 Predator control 57 Harvesting the surplus 57 Restocking 58 Summary 59 Literature cited 62 Index 65 ILLUSTRATIONS Plate Facing page 1. Attwater's prairie chickens (Tympanuchus cupido attwateri) on boom- ing ground Frontispiece 2. Dense cordgrass areas in Aransas County, Tex 4 3. Male Attwater's prairie chicken, showing vocal sacs 10 4. Nest and eggs of Attwater's prairie chicken; Colorado County, Tex__ 14 5. Concealment of nests by Attwater's prairie chicken; Colorado County, Tex 15 6. Chicks of Attwater's prairie chicken; Colorado County, Tex 16 7. Wild indigo (Baptisia) in a closely grazed pasture; Austin County, Tex 22 8. Diversified cover — excellent prairie chicken range; Colorado County, Tex 30 9. Medium-heavy to heavy cover — excellent food-cover conditions in a moderately grazed pasture; Colorado County, Tex 31 10. Shells of eggs at prairie chicken nest destroyed by house cat; Colorado County, Tex 38 11. Native bluestem prairie — well populated by prairie chickens; Colorado County, Tex 39 12. Excellent unburned cover at right of road; inferior burned cover at left; Colorado County, Tex 42 13. Rope counting of prairie chickens on Matagorda Island, Tex 48 14. Fenced plot planted to hegari; Wharton Countj', Tex 56 Figure Page 1. Distribution of Attwater's prairie chickens in Texas 3 2. Movements of a combined brood, Colorado County, Tex 23 3. Rainfall conditions in May in the range of Attwater's prairie chicken in Texas Facing page 34 4. Diagram of the rope count 50 V ATTWATER'S PRAIRIE CHICKEN By Valgene W. Lehmann Collaborator, Division of Wildlife Research, Fish and Wildlife Service^ INTRODUCTION Attwater's prairie chicken {Tympanuchu-s cupido aUwateri Ben- dire) (see frontispiece), might well be called the heath-hen of the South. It is so closely related to the now extinct heath-hen {T. c. cupido) of northeastern North America as to be classified in the same species. Like the heath-hen, Attwater's prairie chicken once -inhabited a large area, its former range including the coastal tall- grass (Andropogon) prairies of southwestern Louisiana and in Texas west and south to Cameron County, near Port Isabel. In certain areas the birds were abundant. Old-timers report that the deep booming courtship calls of the males once reverberated from the prairies with such force and monotony as actually to pain sensitive eardrums. The bird, however, is no longer abundant. It has de- creased in numbers as man has exploited its habitat until now it is threatened with the fate of the heath-hen — extinction. In his "Biological Survey of Texas" Vernon Bailey (1905: 19)' places Attwater's prairie chicken at the head of the list of breeding birds of the Texas coastal prairie. In addition to being a character- istic bird of the region, this prairie chicken is probably the most popular species wherever found. Most people who know it have a genuine appreciation of its color and charm. Rare indeed is the person who finds no esthetic stimulus in the sight of a strutting male on the booming ground, or a brood of downy chicks on the edge of a short-grass flat. Both ranchmen and farmers highly appreciate the prairie cliicken's appetite for grasshoppers, salt-marsh cater- pillars {Estigmene dcraea)^ and the moths of the cotton leaf worm {Alabama argillacea). Under proper conditions prairie chicken hunting provides a high type of sport, and the flesh of the birds, especially that of the young, is highly esteemed as food. 1 Cooperative contribution from the Texas Cooperative Wildlife Research Unit, estab- lished by the Agricultural and Mechanical College of Texas ; the Texas Game, Fish, and Oyster Commission ; the American Wildlife Institute ; and the Fish and Wildlife Service. * Publications referred to parenthetically by date (alone or followed by colon and specific page) are listed in the Literature Cited, p. 62. Explanation of Fkontispiece Attwater's prairie chicl^ens (Tympanuchus cupido attwateri) on booming ground 2 NORTH AMERICAN FAUNA 57, FISH AND WILDLIFE SERVICE The real appeal of the prairie chicken, however, lies in its con- nection with the colorful and eventful early days in Texas. The prairie hen summons memories ; it prompts old-timers to recall when the range was free of wire fences and oil derricks, and rich grasses grew waist high. Thoughtful people deplore the passing of Att- water's prairie chicken, one of the last landmarks of the prairie as it used to be. Highly appropriate was the selection of this bird as a species of major interest by the Texas Cooperative Wildlife Re- search unit.' FORMER DISTRIBUTION OF PRAIRIE CHICKENS IN TEXAS H. C. Oberholser, in a letter to the present writer, states that in his opinion prairie chickens once occurred at some time of year on most prairie areas in Texas. In the main it appears that the differ- ent kinds of prairie chickens in the State occupied separate ranges, and that mixing and intergradation were confined largely to marginal areas. The principal former range of the greater prairie chicken in Texas, as indicated by the records of F. M. Bailey (1927: 130), Gross (Bent 1932: 262), Strecker (1927: 321), and old residents with whom the writer has conferred, was northeastern Texas southwest to the vicin- ity of Waco. Likewise, records show that the lesser prairie chicken was indigenous to northwestern Texas and the high plains region in winter to about Bandera and westward through the "hill country" to the arid plains west of the Pecos River (Bendire 1892: 355, and others). Attwater's prairie chicken, it appears, was largely confined to the better-drained prairies of western Louisiana and Southeastern Texas (fig. 1, p. 3). According to Oberholser (1938: 190-191) the eastern limit of the range of Attwater's prairie chicken was in the vicinity of Abbeville, * So many persons have assisted in the prairie chicken studies that it is impossible to list them all. General supervision of the work was by Walter P. Taylor, leader of the Texas Cooperative Wildlife Research Unit, College Station, Tex. Valuable editorial suggestions were received from W. B. Davis, professor of wild game, School of Agriculture, Agricultural and Mechanical College of Texas ; and from William J. Tucker, executive secretary, Texas Game, Fish, and Oyster Commission. The bulk of examinations of crops, gizzards, and scats was done by Clarence Cottam, Clarence F. Smith, and their associates in the Section of Food Habits, Division of Wildlife Research, Fish and Wildlife Service. In his field work in 1938 the writer was assisted by H. R. Siegler, field biologist of the Research Unit. Many Colorado County landowners cooperated ; among these, M. C. Shindler, Emil Gleuck, Ed Koy, Adolf Renz, and I. V. Duncan deserve special mention. E. P. Haddon, photographer of the Texas Commission, took some of the photographs here reproduced. The assistance of the State game wardens was indispensable. Deserving of special mention are T. S. Boothe, Beaumont ; J. C. Gardner, Hull ; R. Z. Cowart, Rosen- berg ; Ed McCloskey, Victoria ; C. D. Tidwell, Bay City ; G. P. Ferguson, Sinton ; and T. T. Waddell, Eagle Lake. Waddell's contributions to the study were outstanding; he gave most generously of his time, records, and extensive experience. To him, and to all others, the writer is deeply grateful. ATTWATER'S PRAIRIE CHICKEN 3 Opelousas, and Bayou Teche in Louisiana. There are no authentic records of the occurrence of any species of prairie chicken in Texas south of northern Aransas County, except for one bird reported from near Brownsville by Merrill (1879: 159-160). Prairie chickens did not occur near San Antonio, Tex., in 1890, for Babbitt, in Bendire (1894: 130) wrote as follows: "The prairie hen is not found in the Probable Former Ranqe. Preacnf Range FiGiTBE 1. — Present tlistribution of Attwater's prairie chicken in Texas and probable former range in the coastal section. immediate vicinity of San Antonio, Tex., but exists in great numbers south and southeast from here, all at an average distance of 100 miles. * * *" Simmons (1925: 82) submits the records of O. Brinkman and C. D. Oldright as evidence that Attwater's prairie chicken occurred as a breeding bird in the vicinity of Austin. Travis 4 NORTE AMERICAN FAUNA 57, FISH AND WILDLIFE SERVICE County, and in Williamson County as late as 1878, but the accuracy of the data is questionable. Apparently the limit was the northern edge of the coastal prairie, Eoughly, the territory occupied by Attwater's prairie chicken was south of a line extending northeast from Kefugio tlirough Fannin, Thomaston, Provident City, Rock Island, Industry, Welcome, Bell- ville, Prairie View, Tom Ball, Humble, Liberty, Devers, Cheek, and Orange. All this area of approximately 8,500,000 acres in coastal Texas, however, was not occupied. Deciduous woodlands near rivers, as along the San Antonio, Guadalupe, Colorado, Brazos, and Trinity, were used only to a limited extent and only along the mar- gins. Prairie chickens did not occupy the pine forests in Harris County and to the east or the thick mesquite-acacia brush that oc- curred in considerable stands in Calhoim and other western counties as much as 100 years ago. Brackish and salt-water marshes in Or- ange, Jefferson, and Chambers, and less widely in other counties to the west, and extensive cordgrass {Spartina spartinae) flats (pi. 2) in Aransas County and elsewhere in low country bordering the Gulf, probably always were little used by chickens except to a limited extent in winter. There were, however, about 6,000,000 acres of bluestem prairie that probably supported many prairie chickens in favorable years. DIFFERENCES BETWEEN ATTWATER'S AND THE OTHER PRAIRIE CHICKENS During the nineteenth century three kinds of prairie chickens oc- curred in Texas: the greater prairie chicken {Tympanuchus cupido americanus Reichenbach), Attwater's prairie chicken {T. c. attwateri Bendire), and the lesser prairie chicken {T. pallidicinctus Ridg- way). Differences between the greater and Attwater's prairie chick- ens are slight; the lesser prairie chicken is somewhat better characterized. ATTWATER'S PRAIRIE CHICKEN Bendire (1894: 130) described Attwater's prairie chicken as — Smaller than T. americanus [greater prairie chicken], darker in color, more tawny above, usually with more pronounced chestnut on the neck ; smaller and more tawny light colored spots on the wing coverts, and much more scantily feathered tarsus, the latter never feathered down to the base of toes, even in front ; a broad posterior strip of bare skin being always ex]X)sed, even in winter, while in summer much of the greater part of the tarsus is naked. In weight Attwater's prairie chicken, however, is not perceptibly lighter than the greater prairie chicken. The average of 10 males (33.11 ounces, as shown in table 1, p. 5) exceeded by 2.11 ounces the average weight of the greater prairie chicken (31 ounces), as North American Fauna 57, Fish and Wildlife Service Plate 2 c3 •< a ^ !C > Oi jD 01 & t3 a> CO o O c3 Lh 03 bD CS ■a ATTWATER'S PRAIRIE CHICKEN given by Gross (1930a: 40). The average weight of six females (25.7 ounces) was only 0.6 ounce less than that of the female greater prairie chicken (26.3 ounces), according to the same authority (loc. cit.). The weight of Attwater's prairie chickens, especially that of males, varies perceptibly from season to season ; three males obtained at the beginning of the courtship season were appreciably heavier (about 7.5 ounces) than those collected at other times. Darkness of color, tawniness above, and the amount of chestnut on the neck are other characters that vary greatly both seasonally and individually. Winter specimens are generally lighter in color than those collected in spring; they have comparatively little chestnut on necks and backs. The feathering on the tarsus also varies with the season ; the legs of specimens collected in winter are well feathered to the base of the toes. The style of barring on the back and rump, according to F. M. Bailey (1927: 130), is the same for both subspecies, that is, the bars are single, broad, and solid black. Altogether, physical differences between Attwater's and the greater prairie chicken are minor and insufficient to allow accurate field identification. In a series of skins, however, the smaller measurements of wing, tail, bill, and total length and the differences in general ruddiness and buffiness of the underparts are characteristic and serve to separate Attwater's prairie chicken as a subspecies. Table 1. — Weights of 16 AUwatefs prairie chickens County Date collected Weight 1 County Date collected Weight I Grams Ounces Grams Ounces MALES Colorado Do Apr. 17, 1939 > Sept. 1,1937 3 Sept. 4.1937 3 Oct. 23,1937 Nov. 3,1937 Jan. 6, 1938 Jan. 27,1938 Feb. 14,1938 1, 135. 20 682. 00 590. 07 760. 20 874. 00 723. 69 715. 24 726.80 40.03 24.05 20. SI 26.81 30.82 25.18 25.22 25.63 MALES Eefugio Do Colorado.. Austin__ Colorado..- FEMALES Refugio... Colorado Do Feb. 15,1938 do Mar. 18, 1938 Apr. 10, 1938* July 26,1938 Feb. 15,1938 Aug. 20,1938 Aug. 23,1938 1, 103. 70 1, 125. 20 1, 120. 45 1, 077. 26 921. 34 785. 60 722. 89 708. 72 38.92 39 68 Do Do 39.51 38 00 Do 32 50 FEMALES Colorado Do 27.70 25 50 Austin 25.00 • Average weights: Males, ! ' Taken from hawk. ' Immature bird. * Taken from poacher. 3.94 gm. (33.11 oz.); females, 730.49 gm. (25. 70 oz.). LESSER PRAIRIE CHICKEN The lesser prairie chicken is somewhat smaller than either of its relatives. Verne E. Davison, in a letter, reports that 20 mature males from Oklahoma weighed 23.50 to 31.50 ounces and averaged 27.56 ounces. Five hens weighed 23.75 to 27.50 ounces and averaged 25.55 ounces. In other words, these male lesser prairie chickens were, on the average, 3.44 ounces lighter than the male greater prairie chickens (31 ounces) weighed by Gross (1930a: 40); these female 6 NORTH AMERICAN FAUNA 57, FISH AND WILDLIFE SERVICE lesser prairie chickens weighed 0.55 ounces less than the female greater prairie chickens that Gross obtained. According to Bailey (1927: 131), the general coloration of the lesser prairie chicken is paler than that of either the greater or Attwater's, and the color and arrangement of the bars on back and neck also differ. Whereas the bars are single, broad, and solid black in both the greater and Attwater's forms, they are treble, a broad brown bar enclosed by two narrow black ones, in the lesser species. FORMER ABUNDANCE OF ATTWATER'S PRAIRIE CHICKEN Accurate information as to the former abundance of Attwater's prairie chicken is difficult to obtain, although the data at hand record their numbers in certain areas. Many old cattlemen of the coastal prairie have told the writer that in early days the prairie chickens were relied upon to furnish fresh meat for the cattle camps. The task of killing 40 or 50 prairie chickens was menial, the cook of the outfit usually attending to it. In the Eagle Lake area, Colorado County, not more than 35 years ago, prairie chickens were shot as clay pigeons are today. On ap- pointed occasions parties of 10 to 20 or more men encamped in the sandhill country along the Bernard River and hunted the birds for periods varying from a few days to a week or more. At the end of each day the chickens killed, or their heads, were tallied. At the end of the encampment period the party having killed the smallest number paid the expenses of the outing. Waddell and others state that 10 or more piles of prairie chickens, each containing upwards of 100 birds, usually were left at the camp sites to rot or to be eaten by vultures. These encampments began about July 4 and continued through fall and winter. During the summer of 1893 or 1894, in Matagorda County, near Bay City, V. L. LeTulle reports that 71 Attwater's prairie chickens were shot in 2 hours; and that in 1895, at the site of the present town of Van Vleck, he and 3 friends killed 72 birds in an afternoon, and except for poor marksmanship would have bagged many more. Near Wharton, in Wharton County, in the fall of 1894 or 1895, LeTulle found 340 piled where hunters had camped. Mendell Burrell of the Ray Pipkin ranch (Big Hill country, Jefferson County) told the writer that as late as 1920 his domestic chickens were fed under the ranch house in winter to prevent prairie chickens from consuming the grain. In the same area it is said that flocks of from 150 to 200 Attwater's prairie chickens often alighted in the introduced chinaberry trees {Melia azedarach imibraculifera) around the ranch houses and fed extensively on the berries. In verification of this statement W. S. Boothe, State game warden at ATTWATER'S PRAIRIE CHICKEN 7 Beaumont, Tex., presented the writer with a photograph, taken in 1910 on the Wliite Ranch at Devers, showing a dozen prairie chickens in a chinaberry tree beside a house. C. H. Brosig, who hunted Attwater's prairie chickens in the Eagle Lake area for more than 40 years, reported that the birds once were so numerous in the sandhill country bordering the Bernard River that a new covey frequently was flushed while singles from one previously discovered were being pursued. Paul Mundelius noted a similar high density in concentrations of prairie chicken^ in the Sealy-San Felipe section in the eastern part of Austin County in 1873-75. These conditions are seldom found on areas where the pop- ulation is less than one bird to an acre, and they show the former abundance of Attwater's prairie chickens in favorable areas. Not all the coastal bluestem {Andropogon) prairie, about 6,000,000 acres, wa3 equally favorable for prairie chickens even under pristine con- ditions; well-drained, well-populated country (one bird to an acre), as along the Bernard River, did not aggregate more than 900,000 acres, or about 15 percent of the inhabited range. A little more than half, 3,300,000 acres, or 55 percent, of the prairie country was only fairly well drained ; these areas, protected for periods up to 17 years, now have a maximum population of about one bird to each 10 acres. Approximately 1,800,000 acres, or 30 percent, was poorly drained; prohibition of hunting for periods up to 15 years has not produced a population in excess of one bird to each 50 acres on certain of these large ranches. Probably, therefore, the former abundance of Attwater's prairie chicken in Texas approached, but seldom if ever attained or exceeded, 1,000,000 individuals, even in peak years. PRESENT DISTRIBUTION AND NUMBERS Data on the present status of Attwater's prairie chicken (table 2, p. 8) were obtained as follows: At least 90 percent of all fanns and ranches known or thought to have been occupied by the birds in 1937 were visited by the writer in company with local State game wardens. Unless the warden was thoroughly familiar with conditions on the various areas, conference^ were held with landowners, managers, cowboys, guides, hunters, or other persons who were in position to know the status of prairie chickens on particular tracts. After the conferences a general recon- naissance of the areas wa^ made by automobile or on horseback, and notes were taken on the topography, vegetation, surface water, and soil to ascertain the general suitability of the land for prairie chickens, as was done in similar studies previously made in the Eagle Lake area. Then in the light of all available information the range of Att- water's prairie chicken was mapped in each county, and representa- 8 NORTH AMERICAN FAUNA 5 7, FISH AND WILDLIFE SERVICE tive sample areag were selected for intensive study. The birds were then "rope counted" * on the sample tracts. Finally, the total popu- lation of the area was estimated from the data obtained by counting the sample plots. Table 2. — Population status of the Attwater's prairie cMckeri in Texas {1931) Size of tract Census area Territory occupied per bird Popula- tion of whole tract County Size Popula- tion (rope count) Census area Whole tract Acres Acres 1,080 630 Number 56 106 Acres 19.2 5.0 Arre^ Numhtr 42,000 1,610 162 9.9 4,242 6,554 5,000 3 25 Goliad 1 34 11, 554 Dewitt • f 230 873 218 4 14 0 57.5 62.3 Victoria 1 Total or average (3) 65, 535 1,321 18 73.4 892 Wharton i 4,000 4,915 18, 022 49,152 4,200 14,250 32 315 131.2 45.2 76, 089 18, 450 347 53.1 1,433 736 0 12, 288 f 736 0 '50 542 364 219 157 716 482 4 0 1 3 0 0 135.5 1 Harris _ . 219.0 52.3 I Waller .- -.- Fort Bend Total or average (6) 103, 878 2,480 8 310.0 335 f 585 248 269 334 29 2 1 2 20.1 124,0 269.0 167.0 .. . I -" Galveston ' -__ Total or average (7) 54, 067 1,436 34 42.2 1,281 Jefferson - 4,000 700 400 24 1 0 166.6 700.0 Ohamhers Liberty -- - Total or average (8) 91, 724 5,100 26 204.0 449 Grand total or average 457, 135 31, 133 594 52.4 8,711 1 Counties in which prairie chickens occur but in which counts were not made because of scarcity of birds or similarity of the areas to adjoining counties. 2 Numbers in parentheses in total lines refer to areas correspondingly numbered in the map, fig. 1, p. 3. ' Estimates supplied by game wardens. * For an account of the method used in rope counting see p. 49. ATTWATER'S PRAIRIE CHICKEN 9 The known range of Attwater's prairie chicken in Texas, as of September 1937, aggregated only 457,135 acres, as compared with approximately 6,000,000 acres in former times. The range has there- fore been reduced more than 93 percent during the past 100 years or so. The birds are still to be found in the counties of Aransas, Kefugio, Goliad, Victoria, Calhoun, Dewitt, Jefferson, Waller, Galveston, Chambers, Liberty, Lavaca, Wharton, Colorado, Matagorda, Austin, Fort Bend, Harris, Brazoria, and possibly Jackson and Orange, although they have not been reported by reliable observers in the last two for several years. They have definitely been extirpated from Willacy and Montgomery Counties, and their distribution has become restricted throughout the State, especially in the counties of Goliad, DeWitt, Lavaca, Calhoun, Matagorda, Galveston, Fort Bend, Liberty, Jackson, and Orange, if they occur there at all. Prairie chickens had not been seen in Goliad County for at least 10 years prior to 1937, at which time four birds were reported on the W. J. O'Conner ranch. No more than half the grassland range in any county except Refugio is occupied by prairie chickens. In the counties of Mata- gorda, Lavaca, Wharton, Calhoun, Liberty, Jackson, and Fort Bend even less than 10 percent of apparently satisfactory pasture is inhab- ited. Roughly, the available range for prairie chickens is only about 30 percent occupied and, with the exception of about 20,000 acres in southeastern Refugio County, all the occupied area has a sparse population. The total number of prairie chickens in coastal Texas in the summer of 1937 was only about 8,700. The estimated 1937 popula- tion was probably less than 1 percent of the number believed to have occupied the coastal prairie in peak years before it was devel- oped by white men. Approximately 4,200 chickens (or almost 50 percent of the known population of the State) inhabit two ranches in Refugio and Aransas Counties. The estimated population of 4,500 birds for the remainder of Texas is small indeed ! The consensus is that, during the past 10 years, the number of prairie chickens has decreased in all coastal counties except Refugio and Brazoria. In Refugio County there has been a rapid increase in recent years, probably largely because of excellent protection on the Salt Creek and Martin O'Conner ranches. Since 1935 the birds have spread from these onto the O'Brien, Powers, Welder, and Heard ranches near Greta, Refugio County, and probably also into Goliad County. Because of protection during a 5-year close season in Brazoria County (1932-36), R. Z. Cowart, State game warden there believes that in 1937 the number of birds had reached and possibly slightly exceeded the 1927 population level. 10 NORTH AMERICAN FAUNA 5 7, FISH AND WILDLIFE SERVICE The prairie chicken population of the counties of Orange, Liberty, Fort Bend, Matagorda, Jackson, Lavaca, Calhoun, and Goliad, where populations of less than 100 birds per county obtain, may already be reduced to the point where recovery will be extremely difficult or even impossible. So long as any birds remain, however, every effort should be made to build up their numbers. HABITS COURTSHIP AND MATING Prairie chickens do not pair for breeding, but are promiscuous. Males occupy selected courtship stations on booming grounds (see frontispiece) , which are visited by the females. Copulation may take place elsewhere, however, in case of chance meetings. To attract the females, the cocks put on elaborate exhibitions, and their courtship antics are unbelievably weird. Of special interest is the manner in which the booming call is rendered. This call of the male resembles somewhat the sound whur-ru-rrr^ with strong accent on the second syllable. Although it generally lasts about 6 seconds, the call varies in length and tone. In mid- season the calls are characteristically deep and full-throated; later they become shorter and higher pitched, possibly because the males are then less vigorous. The sound of the booming carries for a mile or more on quiet days. It has a ventriloquial effect and often seems farther away or closer than it actually is. During the court- ship season males boom regularly in early morning (sunrise until about 8 a. m.) and in late afternoon (5:30 p. m. until sunset), but calls have been heard at all hours of the day and night. Booming at night is sporadic, however, even during the peak of the courtship season in March, being most common when the moon is bright and when there is little wind. The appearance of the male, while booming, is striking. As a preliminary to uttering the call he stretches his neck forward par- allel to the ground. The erected pinnae, or neck tufts, point for- ward; the spread tail is held vertically or even inclined slightly over the back. The wings are extended downward and held firmly against the body and legs, the primaries almost touching the ground. The whole body appears strained and rigid. A short run forward is followed by vigorous stamping with the feet, which lasts only a few moments, but which under favorable conditions is distinctly audible for 50 feet or more. Inflation of the air sacs, which are actually but one sac with two lateral portions (pi. 3) is synchronized with the stamping. The first syllable of the booming is given before stamping ends, the male quickly jerking his head downward as he begins the call and keeping it there until the air sac is deflated. North American Fauna 57, Fish and Wildlife Service Plate 3 Male Attwater's prairie chicken, showing vocal sacs. (Photo from Texas Game, Fish, and Oyster Commission.) ATTWATER'S PRAIRIE CHICKEN 11 The call of Attwater's prairie chicken apparently is given in the same manner as was that of the extinct heath-hen, its near relative. Gross (Bent 1932: 272) describes the booming mechanism of the heath-hen as follows : The sacs do not produce the notes, as was thought by some of the earlier ornithologists, but have much to do with modifying the sounds produced by the syrinx (the vocal mechanism at the juncture of the bronchial tubes). The sounds are produced by the air forced from the lungs, which vibrate specialized membranes of the syrinx under control of a complex set of muscles. The sound waves then issue through the trachea and glottis to the pharynx. In the production of such notes as the ordinary cackle the mandibles are opened and the air accompanied by the sound waves issues out of the mouth. In the tooting [booming] performance the mandibles are tightly closed, the throat patch is elevated, and the tongue is forced against the roof of the mouth (palate) by the mylohyoides muscles, which close off the exit through the Internal nares. The tongue is bent in such a way that it causes the glottis at the base of the tongue to open directly in front of the esophagus. The air now coming from the respiratory system is forced to fill the modified anterior end of the esophagus, or gullet, which becomes distended like a balloon. While the air sac is filling, the sound waves produced by the syrinx beat against these tense drumlike membranes, which serve as resonators for the sounds and give them their great carrying power. The booming call does not complete the vocabulary of male prairie chickens at courtship time. The rendition of additional calls, all distinctly henlike, is described as closely as possible on p. 12. On windy days cackling sounds, like Nos. 1, 2, and 3 in the list, carry farther than booming. The call note picoik (No. 14) dominates when hens visit the courtship grounds. Observers may identify grounds where females are present by this piooik call. Males do not confine their courtship activities to vocalizing, and fights are common. Opponents usually approach each other, utter- ing peculiar whining notes, with necks outstretched, ear tufts erected, tails spread, wings drooped, and air sacs deflated. Then, as if pos- sessed of the same thought, they suddenly hop off the ground, wings beating rapidly, and clash in midair. These bouts are usually dis- continued after three or four flurries, and the victors seem satisfied after pursuing their opponents for short distances. Many feathers are frequently lost, but fights seldom if ever end fatally. Males sometimes engage fancied opponents, as clumps of weeds or tufts of tall grass, and at other times they joust and bluff for periods up to 30 minutes or more without striking a blow. With necks out- stretched, heads held a few inches apart, and wings dangling loosely, they resemble domestic roosters fighting. At intervals males flutter into the air to heights of 3 to 5 feet, alighting nearly on the spot whence they arose. Their surplus energy apparently must be expended 303807°— 41 2 12 NORTH AMERICAN FAUNA 5 7, FISH AND WILDLIFE SERVICE in one way or another, although activity sometimes lags for brief periods. CALL OF MALE PRAIRIH CHICKENS ON COURTSHIP GEOTJHDS 1. Ca-ca'-ca-ca-ca-ca-ca-cor-caa-ccui—. All except last two notes given rapidly. 2. Ca-ca'-caa, ca-ca'-caa Rapid. 3. Ca-ca-ca-ca'-ca Rapid, accent on second to last syllable. 4. Ca-ca-ca-corkeeee All except last syllable given rapidly. 5. Ktmeee, ca-ca-ca-oa-ca-ca First syllable drawn out^ remainder given rapidly. 6. Kwerr-hwerr-pwah First two syllables drawn out. 7. Ewier-kwier-kicier-kivier All syllables drawn out. 8. Pwark or pwarrk Medium rapid. Often preceeds cackling or booming, carries as far as or farther than booming notes under certain weather conditions. 9. Caaa-caaa-caaa-caaaa Slow and drawn out. Sounds almost ex- actly like protests of a domestic setting hen that is disturbed. 10. Piviek, pioark Medium rapid. 11. Piviek, pwiek, pwiek All notes drawn out with emphasis on the iek. 12. Pioiek, ca-ca-ca-ca-ca-caa Pause after first note, cackle given rapidly. 13. Pivk-pivk-pwk-pwk-pick-pwk Harsh notes executed rapidly, but in a subdued tone. 14. Pwoik, pwoik, pwoik, pwoik Executed rapidly and with much vigor. These notes predominate all other calls when a female approaches a courtship ground. 15. Kliee, kliee, kliee; corca-ca-ca— Kliee's drawn out ; ca's given rapidly. This is a prominent call in early spring. 16. Kwoo, kivoo; kwah, kivah Rapid. Another prominent early season call. The performers do considerable feeding when they first arrive on the courtship ground, and certain of them feed sporadically throughout their stay. At other times individuals, sometimes an entire group, sit or stand in their places and look about. Rest periods terminate abruptly, however, when a male recognizes a real or fancied challenge, or when a hen appears. While the male is bold and noisy during the mating season, the female is demure and shy. Hens visit the courtship grounds irregularly except early in March. Even in well-populated territory a week sometimes elapses before the persistent male performers are rewarded by female company. When on or near a drumming ground, hens usually appear little interested in the spirited antics of the ob\aously excited males. Sometimes, however, they walk among the contestants and mate with one or several of them. Hens usually remain at the courtship areas briefly; usually they stay only a few minutes before leaving to feed elsewhere or fly to the vicinity of their nests. ATTWATER'S PRAIRIE CHICKEN 13 In Colorado County signs of the approaching breeding season w^re noted early in January (1937) and late in December (1938) when cer- tain males, probably the most vigorous, pecked at and otherwise bullied their fellows as the flocks left the roost or fed early each morning. A few weeks later, early in February (1937), and late in January (1938), males assembled early in the morning on short-grass areas that later served as courtship grounds, and fought and maneuvered for choice positions. For a week or more, calls consisted largely of miscellaneous squawks and cackles, and fights, though frequent, were of short dura- tion. Males occasionally attempted to drum or boom, but their notes lacked midseason depth and vigor. Females, still in winter flocks, seemed indifferent to the proceedings. It was not until February 12, in 1937, and January 26, in 1938, that booming was commonly heard, and each year, after 2 to 3 weeks, flocks of females generally broke up and the courtship season was well under way. During both 1937 and 1938 courtship activity was at its peak in March, continuing through April and ending on May 20, in 1937, and on May 21, in 1938, when the last booming calls were heard. Key areas during the courtship season are the booming grounds where males assemble each morning from daybreak until about 8 a. m. and each afternoon from 5:30 p. m. until dark and give their courtship display. The preferred booming ground is a short-grass flat, an acre or so in extent, surrounded by an area of medium to heavy grassy cover suitable for nesting. Of several hundred sites observed during 3 years (1936- 38) only one was on ground elevated enough to be termed a small knoll. The others were even with or slightly below the adjacent land surface. Stoddard (Bent 1932: 245), discussing the greater prairie chicken in Wisconsin, says that "the 'cooing' ground [courtship ground] at the sandy west end of Sauk Prairie has been used each spring for over 30 years, the birds always using the same knoll whether in rye, stubble, or grown to grass." Courtship grounds of Attwater's prairie chicken do not show the same degree of permanence. Cultivation seemingly re- sults in immediate eviction, whether the crop is rice, corn, cotton, or something else. Likewise, the birds do not use fallow fields except where cultivated land is the only other environmental type available, or where the fallow land has aged to the extent that its surface and vegetation are nearly identical with that of nearby grassland. Even those court- ship grounds that are in pastures may or may not be occupied each year for a series of years. Of 10 such grounds, on which records were ob- tained from 1936 through 1938, only 5, or 50 percent, were occupied each year. Their populations were fairly stable (see table 3, p. 14). Of the others, 2 were occupied in 1936 and 1937 ; 2 were unused except in 1936 ; and 1 was occupied in 1936, in part of 1937, and throughout the entire season in 1938. There was little variation in the prairie chicken 14 NORTH AMERICAN FAUNA 5 7, FISH AND WILDLIFE SERVICE population of the pastures in which these courtship grounds were situ- ated, but in every instance the vegetation on or near the study areas varied in density through grazing or burning. Cover changes on and near courtship areas influenced their attractiveness to the birds, possibly to the point of determining whether they would be occupied and by how many individuals. Table 3.- -Occurrences in 3 years of male prairie cMckens on 5 courtship grounds in Colo7~ado County Observations Birds observed Name of pasture Extremes Averages 1936 1937 1938 1936 1937 1938 1936 1937 1938 Thomas 2 2 2 2 2 11 8 14 13 20 6 6 6 11 12 7- 9 9-11 5- 6 6- 8 7- 7 6- 9 3-10 3- 9 5-11 0- 8 4-11 5- 8 3- 8 5-13 6-14 8.0 10.0 5.5 7.0 7.0 7.0 6.0 8.0 9.0 6.0 8.0 Do 7.0 Do 7.0 10.0 Everett 10.0 Total or average 10 66 42 7.5 7.2 8.4 NESTING WMle the males are still engaged in their courtship performances, the females quietly select and improve the nest sites and attend to laying, incubating, and hatching the eggs and rearing the young. Nests (pi. 4) are made on the ground. Of 19 examined in 1937 and 1938, 17 were in long-grass pastures, 1 in a hay meadow, and 1 in a fallow field. All were in dead grass of the previous year's growth. Fifteen (about 76 percent) were on or near well-drained mounds or ridges, and 4 were in poorly drained situations. In a choice of nest sites, cover appeared of more importance than topog- raphy and the structure of the soil. Twelve (63 percent) of the study nests were situated within 10 yards of well-marked trails, possibly because prairie chickens dislike walking through heavy matted vegetation when approaching or leaving their nests. Cattle make many trails, thereby improving nesting areas. Study nests were found always within a radius of half a mile to a mile from occupied booming grounds. Sometimes the sites were rather distant from acceptable feeding territory, although flights of up to a mile seemed to inconvenience the birds very little. Nests were merely shallow depressions, about 7 inches in diameter, lined with bits of dead grass, twigs, and a few feathers, presumably from the females. All were more or less roofed over because of the lapping or bending over of surrounding vegetation. Entrances faced in various directions with no preference shown. There was consid- erable variation in degree of concealment (pi. 5), at least according to human standards; 5 nests being excellently, 10 well, and 4 poorly, concealed. Kapid new plant growth in April and May aided ma- North American Fauna 57, Fish and Wildlife Service Plate 4 OJ « 5 P O 3 5 -2 ^ > CL, >< North American Fauna 57, Fish and Wildlife Servii PLATE 5 '.■^- ' ^ QJ O >i <»" r^- ^O ATTWATER'S PRAIRIE CHICKEN 15 terially in hiding nests ; consequently, some nests that were relatively exposed when found were well hidden later. Wild indigo {Baptisia sp.), vetch {Vicia ludoviciana) , phlox ( Phlox drummondii)^ peren- nial ragweed {Amhrosia psilostachya) , dogfennel {EupatoHum sp.), and panic grass {Panicuin sp.) were green plants that aided con- cealment materially by mid-May. In Colorado County, favorite nesting materials were dry bluestem grass {AndropogoTi scoparius), and paspalum {Paspalum dilatatum). The earliest date for a nest containing eggs was reported by Wad- dell near Egypt, Wharton County, February 25, 1925; the latest record is that of a nest in Colorado County in which the clutch was completed May 29, 1938. In both 1937 and 1938, however, the peak of the laying season in Colorado County was late March and early April. Hens always laid in the morning, usually from 7:30 to 9, flying to the vicinity of their nests when ready. After cautiously looking about or feeding a bit longer, hens walked to the nests and remained there for from about 20 minutes to an hour. The laying completed, they regularly walked about 20 feet from the nest, scanned the landscape, and flew away. Since incomplete clutches were un- guarded except during about an hour each day, they were especially vulnerable to natural enemies. Hens under observation normally laid an Qgg a day until the clutch of 8 to 15 was complete, but sometimes they failed to lay for periods of 1 to 3 days. Clutches usually contained 12 eggs, and lay- ing was generally completed in about 2 weeks. The period of egg laying was sometimes extended, however, when nests were destroyed. Three hens, each the only resident on a small unburned plot, re- nested during 1937, one of them three times. New nests, however, were placed 5 to 20 yards from old ones, and were less effectively concealed. Destructive agents had even greater opportunities to take the later nests, as they did in four out of five cases. Since booming ended by mid-May, the period for mating was short. Late broods were invariably smaller than early ones, probably because late clutches were small, their hatchability low, or their mortality heavy. A successful season depends largely on the fate of early nests, so that a primary objective of management should be to safeguard these attempts. Twenty-nine eggs of Attwater's prairie chicken measured by Bent (1932: 264) averaged 42.3 by 31.5 millimeters in size, showing ex- tremes of 44.9 by 32, 42.4 by 33.5, 38.8 by 28.9, and 39.8 by 28.6 millimeters. Newly laid eggs were dull cream or bluish buff in color, some of them minutely specked with red. During incubation the color of the eggs became dull and the shells shiny. Incubation began at from 1 day before until 4 days after the last egg was laid. 16 NORTH AMERICAN FAUNA 57, FISH AND WILDLIFE SERVICE Except for two feeding and resting periods daily, extending from about 7 to 8 a. m. and from 5 :30 to 6 :30 p. m., hens incubated con- stantly. When incubation was advanced, morning feeding was fre- quently dispensed with. Two clutches pipped approximately 23 and 24 days after setting began, in each instance requiring about 48 hours longer to hatch. Of 71 eggs in 7 nests, only 3 (about 4 percent) were infertile, 66 hatching successfully. Seemingly, fertility and hatchability are high under favorable conditions. The hatching period was evidently a time of danger. Chicks peeped incessantly and scrambled in and out of the nest. Nests emitted strong odors, apparent even to man. Females at hatching time appeared nervous and shifted their positions frequently. Unless disturbed, however, they did not leave until the last egg had hatched, after which they deserted the nests. In 1937 a nest in which all young were hatched by 11 : 50 a. m. on May 15 was vacated by 3 p. m. that day, and a brood that was hatching at 8 : 30 a. m, on June 2 was gone 24 hours later. One hen left before 2 pipped eggs were hatched and before the natal down on some of the young was dry, probably because fire ants {SoUnopsis) had entered the nest. GROWTH AND DEVELOPMENT OF YOUNG When leading chicks from the nest, old birds traveled through the lightest cover or followed trails, probably because heavy matted vegetation impeded progress and increased the chance of chicks get- ting lost. Cow trails were favorite travel ways. Chicks ranged in front, behind, and on both sides of the hen over an area 1 to 5 yards in radius. Interruptions for sporadic feeding and for frequent brooding, which was probably more necessary for assembling than for warming the young, made progress slow. Hens with chicks less than 10 days old (pi. 6) seemed mainly concerned with watchfulness and brooding. Occasionally they caught available insects or nipped off a few green leaves or buds, but they did little continuous feeding. When danger threatened, they gave a warning call, best described as a low kwerr^ kwerr, kiuerr, and slowly skulked through the grass with head lowered and wings dangling loosely, almost touching the sod. Young birds "froze" with their bodies closely pressed to the ground. Decoy efforts of adult females were never so energetic as those of bobwhites under similar circumstances. When hens were flushed, the chicks in hiding (pi. 6) became impatient after 3 to 5 minutes, and peeped and ran about in spite of the fact that the object of suspicion remained. After the immature birds of 2 to 3 weeks of age could fly fairly well, females accompanying them did not decoy, but always flushed freely, the young doing likewise. Chicks that were less than a week old were brooded quite often, probably in all for about 50 percent of the daylight period. Ten birds North American Fauna 57. Fish and Wildlife Service Plate 6 Ahopc, Chicks about 10 days old; Colorado County, 1 ex., n|)i)i().\iiiiai«-ly (1 miles north of Eagle Lake, May 3, 1938. Below, Chicks hiding; Colorado County, Tex., approximately i^Yz miles north of Eagle Lake, May 3, 1938. (Photos from Texas Game, Fish, and Oyster Commission; E. P. Haddon.) ATTWATER'S PRAIRIE CHICKEN 17 about 2 days old were brooded 42 minutes out of the li^ hours during which they were watched on May 4, 1937. Their position during brooding was interesting. Hens squatted low with legs at an angle of about 30 degrees with the ground. Wings were drooped and feathers of the underparts were ruffled. Some chicks scrambled up and under the wings. When the brooding hens were frightened and suddenly stood erect, usually only two or three chicks were visible; the others, however, tumbled from beneath her wings a few moments later. As the chicks grew older, the time spent brooding diminished ; those 2 weeks old apparently were brooded little except early in the morning, during inclement weather, and at night. Newly hatched chicks are about the gize of day-old bantams, and their coloration is nearly identical with that of young bronze turkeys. The basic, buffy yellow is streaked with gray on head and upper- parts. Growth and development are rapid. Wing feathers appear almost at once; week-old chicks have primaries approximately five- eighths of an inch long. Chicks fly when 2 weeks old. Except for differences in the length of the tail and legs, they are about the size of English sparrowg. When 3 weeks of age, youngsters are almost as large as starlings and can make sustained flights of 40 yards or more. At 4 or 5 weeks, young birds approximate the size of mature bobwhites, and often fly a hundred yards before alighting. When 6 or 7 weeks old, the young are about half grown and at 8 or 9 weeks they are three-fourths the size of adultg. Youngsters 10 to 12 weeks old can scarcely be differentiated from the old birds in the field. Weight evidently does not increase as rapidly as size, however, for two birds approximately 3 months old were more than a pound lighter than mature individuals. As young prairie chickens grow in size, all cannot, of course, main- tain a brooding position under the sheltering body of the mother. Usually by the time they are about 3 weeks old some are forced out- side; there they sleep with bodies pressed closely to that of the hen. When 4 to 5 weeks of age, two or three chicks sometimes crowd under their mother, but the remainder roost from a few inches to about 2 feet away. At 6 to 7 weeks, young birds adopt the roosting formation of adults. Flocks of Attwater's prairie chickens sleep about a foot or so apart, the individuals facing in different directions. Boosting spots vary in size from 1 to 3 square yards or more, depending on the number of birds in the group. The number of scats left at a roosting site is not an absolutely accurate index to the number of birds in a flock, because slight shifting of individuals during the night brings about the deposition of more than one pile by a bird. Chicks about 2 weeks old take vigorous dust baths, a habit that is indulged in regularly throughout life when dry, powdery material is 18 NORTH AMERICAN FAUNA 57, FISH AND WILDLIFE SERVICE available. Prairie chickens generally dust during the midday rest period that extends from about 10 a. m. to 4 p. m. Old pocket gopher mounds and cattle wallows are favorite places. Some birds use the same dust bath more than once. BROOD SIZE The size of the brood generally decreases with the age of the young. Of 48 broods on which accurate counts were kept (table 4, below) 6 from 1 to 3 days old contained 64 young, averaging 10.6 birds each. Three broods estimated to be 5 to 10 days old contained only 14 chicks averaging 4.6 each. Four broods 15 to 27 days old had 22 young, or an average of 5.5. Fifteen families over 4 and under 6 weeks of age aggregated 80 young and averaged 5.3. Twenty groups over 6 weeks totaled 80 young and averaged 4 each. The average size (5.3 young) of 15 families, estimated to be over 4 but under 6 weeks of age, was exactly half the average size (10.6) of 6 new broods. The average size (5.3) of 15 families over 4 but under 6 weeks old was but slightly larger than the average size (4.0) of 20 families older than 6 weeks. Therefore, it appears that juvenile mortality is heaviest during the first 4 weeks and comparatively light thereafter. Table 4. — Size of iroods and number of chicks counted during May, July June, and County Date Family groups observed Chicks per group Chicks per average group May 4 May 15 May 18 May 23 May 28 May 29 May 31 1 1 1 3 3 1 2 10 12 12 2,4,2 7, 9, 11 8 4,8 10.00 Do 12.00 Do 12.00 Do - 2.66 Do 9.00 Do --- 8.00 Do - 6.00 12 89 7.41 June 2 June 3 June 8 June 10 June 24 4 1 2 2 3 6, 9, 4, 2 10 3,3 4,8 5,4,3 6.33 Do 10.00 Do 3.00 Do 6.00 Jefferson 4.00 Total or average for June 12 61 5.08 July 1 July 8 July 14 July 17 July 19 July 26 3 2 1 4 6 2 5,5,6 3,3 7 10, 8, 1, 3 10, 2, 2, 4, 5, 2 10,5 5.33 Colorado 3.00 7.00 6.00 Do 4.16 Colorado 8.00 Total or average for July 18 92 5.11 Aug. 12 Sept. 2 Sept. 3 Sept. 4 1 3 1 1 3 5,3,3 3 4 3.00 3.66 Do 3.00 Do 4.00 Total or average for August, September 5 18 3.60 48 263 5.48 ATTWATER'S PRAIRIE CHICKEN 19 JUVENILE MORTALITY Although much remains to be learned about juvenile mortality, its causes were fairly well established in some instances. Chicks are sometimes trapped and drowned in rice fields at the time of flooding (usually about May 10). In 1925, near Egypt, Wharton County, Waddell and others picked up hatfuls of chicks and carried them beyond the levees. In 1937 a farmer near Eagle Lake similarly res- cued a brood. The number of chicks annually saved from this hazard, however, is probably insignificant in contrast to those lost. Prairie fires kill young and, as stated on page 42, burning is still common in certain areas at nesting and brooding time. Unfavorable weather, especially rains (pp. 32 to 35) and natural enemies (p. 39), account for the death of some young birds, but no small percentage of these may be chicks that are lost. Chicks stray from the brood more often than one might suspect. During April, May, and June, 1937, no fewer than 13 strays were seen, all under 4 weeks old. Usually they occurred as singles, but sometimes in pairs and trios. How the youngsters became lost, of course, was usually unknown, but several reasons were apparent. The characteristic loose feeding formation of broods possibly con- tributed to straying; also, broods usually scattered widely and flew far when disturbed; and, possibly most significant of all, adults did not appear to have a highly developed rallying call that doubtless would be of assistance in reassembling youngsters. Lost chicks evidently join other groups occasionally, as hens ac- companied by young of varied sizes were several times noted in 1937. Once two chicks, about 2 and 3 weeks old, respectively, were seen with two molting males. Higher population levels might increase the frequency of adoptions. FAMILY DISINTEGRATION Many young Attwater's prairie chickens 6 to 8 weeks old leave the family groups and take up life on their own, but, as is true with domestic chickens, all young do not leave the hen at the same time; disintegration of the family group is gradual. Some young remain with the hen well into the fall. Unattached young, 6 weeks of age or older, as distinguished from lost chicks less than a month old, became noticeable late in June and they were frequently seen after July. Family disintegration after 6 weeks or thereabouts is normal. Young prairie chickens at that age seem as capable of foraging and resisting adverse weather as are the adults. 20 NORTH AMERICAN FAUNA 5 7, FISH AND WILDLIFE SERVICE ANNUAL INCREASE The actual survival of young prairie chickens (table 5, below) prob- ably is always well below the potential yield (12 or so young from each hen) even when favorable weather conditions obtain during the critical breeding season. Table 5 . — Young and adult Mrds observed in census after June 30, 1937 Date Area Adults Young County Males Females Sex un- known Total Families Strays Total Brazoria Victoria July 1 July 14 July 17 July 19 July 26 July 27 Aug. 12 Sept. 1 Acres 585 921 1,080 530 1,450 851 1,282 2,000 Number 2 1 1 3 0 2 1 1 Number 4 1 4 8 2 0 1 5 Number 2 6 23 S3 4 2 2 8 Number 8 8 28 64 6 4 4 14 Number 5,5,6 7 10, 8, 1, 3 10, 2, 2, 4, 5, 1 11,5 3 3 5,3,3 Number 1, 1, 1, 1, 1 1,2 2, 1, 1, 1, 1 1, 1, 2, 1, 1, 1 2,3 1 1 1,2,1,3 Number 21 10 Refugio 28 Do 32 Colorado. Brazoria Harris . . 21 4 4 Colorado 18 Total 8,699 11 25 100 136 103 35 138 In a rope count on or after July 1, 1937, 138 young as compared with 136 adults (about 1:1) were enumerated on an area of more than 8,699 acres. At this time most of the counted birds were 4 weeks old or more and were beyond the age when mortality is thought to be most severe. The increase on the counted areas, then, was only about 100 percent in spite of the fact that food, cover, and weather conditions were favorable. A 100 percent increase of prairie chickens in any one year is very good, and the arguments for long open seasons and large bag limits, based on the potential annual increase (12 chicks for each hen, or about 600 percent a year), evi- dently are fallacious. FLOCKING Late in summer and early in fall, the prairie chickens displayed no marked tendency to combine into stable groups. In August and September of 1936 and 1937 well over half the birds observed in Colorado County were recorded as singles, pairs, and trios, although small groups of 4 to 6 were not uncommon. Occasional larger flocks were recorded, but these appeared to be temporary. In Colorado County, at about noon on September 1, 1937, a flock of 15 to 25 birds was noticed in a cotton field. On the following 3 days at the same hour 11, 15, and 9 birds, respectively, were present in that field; but they had come in between 9 : 30 and 11 : 30 as singles, pairs, and in small groups not exceeding 5 birds each. Between 4 p. m. and dark they left the field as they had come. Again in Colorado County, at 6 p. m. on September 3, 1937, another group of 16 birds found in a pasture came together as follows : At 5 : 40 p. m. a group ATTWATER'S prairie CHlCKElSr 21 of 8 flushed approximately 1 mile from the spot where the large flock was later noted, and as they flew over the prairie, a pair, a single, a trio, and another pair joined the original group. AH set- tled and fed together for a time, but the be\^ disintegTated by dusk. Like instances suggest that early fall flocks of a dozen or so birds are unstable groups brought together largely by chance. In fall, after the weather turned cool, groups of prairie chickens became the rule rather than the exception. Early November bevies generally contained 4 to 12 birds each, but large flocks became in- creasingly common from about December 1 to the onset of the breed- ing season. Late in winter (January) Guy Ferguson, State game warden, Sinton, Tex., observed flocks in Kefugio and Aransas Coun- ties that contained more than a hundred birds. Wardens Waddell in Colorado, Austin, and Wharton Counties, and McClosky in Vic- toria County, reported winter aggregations of about the same size. In 1936, J. O. Linney, foreman, Salt Creek (Hallahan) ranch, Re- fugio and Aransas Counties, noticed late winter concentrations esti- mated to contain 250 to 300 individuals. The writer has not observed such large winter flocks, possibly because he has not made observa- tions in areas where the birds were sufficiently numerous. January assemblages of 25 to 35 birds were not uncommon, however, in Colo- rado County. Despite the fact that large flocks became more fre- quent from November until the breeding season, small groups of 8 or fewer birds or singles were always to be found. All packs ob- served in Colorado County late in November, December and January contained birds of only one sex. Late in January, residents of the coastal country eagerly listen for the first booming calls, which, besides promoting rapid disintegration of winter flocks, signal the departure of winter and the coming of spring. seasonal movements Spring Comprehensive data on prairie chicken movements are lacking, but the records obtained in 1937 are of interest. Two broods that were observed two or more times daily from the time the}?^ were hatched until they were 7 and 12 days old, respectively, were, at last observa- tion, less than half a mile from the nest sites. Another brood, esti- mated to be 8 days old when first discovered on June 2, was within 150 yards of the same spot at various hours during the next 6 days. A fourth brood, about 3 days old on April 29, remained within 400 yards of a certain windmill from April 29 through May 31. A 640-acre pasture that contained four broods, all under 2 weeks of age when rope counted on June 2, likewise harbored four broods 10 days later. 22 NORTH AMERICAN FAUNA 57, FISH AND WILDLIFE SERVlCiJ If this is indicative, the prairie chickens under observation spent their first several weeks of life in close proximity to the places where hatched. The daily cruising radius of a brood apparently was small, seemingly less than 300 yards in the case of birds under 4 weeks old in a favorable environment. Some 30 broods observed between May 1 and June 1 were found in light cover on or near hardpan flats and recent burns, indicating a distinct preference for those types of habitat. SUMMEE An extensive movement involving both young and adult prairie chickens in Colorado County began about June 1, 1937, when many of the young were 3 to 5 weeks old, and lasted until about June 30. The sudden scarcity of the birds in places where they had been common only a few days before was striking. A 1,000-acre pasture that contained 37 individuals (16 old and 21 young) on June 2, held only 16 in all on June 10. As the prairie chickens decreased in some pastures, they increased in others. A 460-acre pasture that was un- occupied on May 1 contained 14 birds on June 8 and 23 on July 26. This movement from the spring range was by stages. One brood that was watched closely made trips of approximately 1 mile, three- fourths mile, and 1^ miles in 6 days from June 2 through June 8. After the first major movement, this family remained for 3 days in an area less than 500 yards in diameter ; their droppings in piles formed a triangle with sides of 5, 15, and 17 yards, respectively. The move- ment of a combined brood of 3 hens and 16 to 25 young are recorded in figure 2, p. 23. Leopold (1933: 291) reports thai^- All observers unanimously and independently report a strong tendency for the grown young of most species of grouse to seek the vicinity of drinking water in late summer and fall, but whether they do this out of choice or necessity is not known. The early summer movement of young and adult Attwater's prairie chickens also was to the vicinity of surface water, but it was to water near which there also was shade. Pastures having an abundance of surface water but little or no shade-producing cover had few if any birds after mid-June. Likewise, places in which dense stands of weeds, shrubs, or tall grass were abundant, but sur- face water scarce, were sparsely populated. More than 95 percent of the more than 600 Attwater's prairie chickens observed from June 24 through September 4, 1937, were in heavy cover within a mile, generally within less than half a mile of surface water. The beginning of the summer movement is synchronous with the drjdng up of the wild indigo {Baptisia, pi. 7), a plant that fur- nishes the principal shade on burns and heavily grazed areas from April through May. Prairie chickens require abundant shade in sum- North American Fauna 57. Fish and Wildlife Service PLATE 7 B50688: B49718A Above, Wild indigo {Baptisia) in a closely grazed pasture; Austin County, Tex., approximately 8 miles southeast of Sealy, April 10, 1938. Below, Shocked grain and wa.ste in rice fields sometimes attract prairie chickens; Colorado County, Tex., 3 miles northeast of Eagle Lake, September 5, 1936. (Photos by V. W. Lehmann.) ATTWATER'S PRAIRIE CHICKEN 23 mer, for birds that were herded from such cover at midday panted vigorously, drooped their wings, and showed other signs of discomfort. They evidently rarely drink from surface water. In 1937, birds near water were closely observed, but only one was seen to drink during the entire summer. That was in Colorado County on June 1, 1937, when a chick about 3 weeks old drank a few times from a puddle formed by water from a leaking windmill. The soft mud bordering ponds in inhabited prairie chicken range in Brazoria, Colorado, and Austin Counties was examined thoroughly at various times, but tracks of this species were never found. Grasshoppers FiGUBE 2. — Movements of a combined brood, May 1 to July 26, 1937, Colorado County. Birds seen in areas as follows : 1, May 1 to 28 ; 2, June 10 to July 10; 3, July 15 to 26. and other favorite foods were frequently more abundant in surmner in heavy cover near water, but the food factor was not thought to be of great importance at the time. The summer movements of prairie chickens to heavy cover near water are not satisfactorily ex- plainable on the basis of cover, water, and food, but these habitat conditions must be provided where stable populations are desired. After they found a satisfactory summer range, the prairie chickens moved little until fall, unless their summer territory was depleted or that nearby was more suitable. The population of a 460-acre pasture in Colorado County remained at nearly the same level (25 24 NORTH AMERICAN FAUNA 5 7, FISH AND WILDLIFE SERVICE to 36 birds) from July 26 through September 3, 1937. The birds that rested in this area at noon each day, however, foraged and roosted largely in adjoining pastures, but their range was never more than 114 miles and usually under half a mile. Rains in 1937 sufficiently heavy to collect in low spots caused tem- porary spreading of prairie chickens from previously occupied areas. As the temporary water disappeared, however, the birds again con- centrated. Fall and Winter Populations that had been rather stable in certain pastures in Colo- rado County during the summer months of 1937 began shifting early in fall. About 25 birds that were summer residents of the M. Shin- dler cotton field from July through August were absent after Sep- tember 4. Two thousand acres of regularly censused pasture where prairie chickens were common in summer contained only 9 birds when rope counted on October 22. While the birds decreased generally in the large pastures, they increased around small farms near Sealy, Austin County ; Lissie, Wharton County ; and Bernardo and Chester- ville, Colorado County — territory 5 to 10 miles removed from the pastures in which birds had been most common during the preceding spring and summer. Distances traveled daily were evidently great in some instance^. A bird killed by a farmer at 8 a. m. on September 1, 1936, was L .lown to have traveled at least 3 miles since dawn, because its cror was filled with rice and the nearest rice field was that distant. Two in- dividuals, observed for 2 hours on the afternoon of October 22, 1937, traveled approximately ly^ miles southeast of the point where first seen. When finally flushed, they flew an additional 2 miles or so in the same direction. A flock of four birds observed from 4 p. m. to 6:15 p. m. on January 4, 1938, traveled more than 1% miles. The movement was in a circular direction, however, for at nightfall, the birds were less than half a mile from the point where they were first observed. Cool weather, fall rains, and a seasonal abundance of food and cover, especially in the vicinity of farming co nmunities, probably were important in promoting the general fall scattering and the long daily trips the prairie chickens made in territory that was sparsely populated at other seasons. The birds reconcentrated in large pastures, however, as fall passed into winter. The population of the Everett pasture (640 acres), Colorado County, increased from November 3, 1937, through January 28, 1938 ; five censuses during that period showing 46, 58, 56 to 58, 73, and 84 birds, respectively. Excellent food and cover conditions prevailed, for the area was lightly grazed. This increase in the number of birds apparently resulted from influxes from adjoining areas. After ATTWATER'S PRAIRIE CHICKEN 25 November 15, few fluctuations in numbers between different pastures were reported by fence riders and others. Pastures that contained the greatest numbers in November and December 1937 also harbored the largest breeding populations the following spring. The data at hand show that late in fall, probably by about Novem- ber 15, the prairie chickens move to pastures where food and cover conditions are adequate. Having found such an area, they remain until spring. Probably the best way to attract a good breeding population, therefore, is to provide suitable food and cover conditions during the preceding winter. FOOD Data on the food of Attwater's prairie chicken were derived mainly from analyses of 21 stomachs (crops, or gizzards, or both) and more than 200 droppings (scats). Additional information was obtained by watching feeding birds at close range through field glasses. Of the 21 stomachs, 18 were of adult prairie chickens, 2 of chicks ap- proximately 10 days old, and 1 of a juvenile about 7 weeks old. Specimens were obtained as follows: 6 in winter (January and February), 5 in spring (April and May), 5 in summer (June through August), and 5 in fall (September through November). J. H. Gaut collected 3 stomachs near East Bernard, Wliarton County, in May 1905. Over the period beginning September 1936 and ending Au- gust 1938, 2 stomachs were obtained in Austin County, 4 in Refugio CounVy, and 12 in Colorado County. As the crops and gizzards of alH birds found killed by automobiles, predators, poachers, and from other causes were saved, it was necessary to collect only 11 specimens to balance the series according to seasons. Except during the breeding season, adult prairie chickens regu- larly feed twice daily, early in the morning (dawn to about 8 a. m.), and late in the afternoon (4 p. m. to dark). Occasional bits of food are picked up throughout the day, but the gullets of specimens col- lected about noon are usually empty or nearly so. The food capacity of prairie chickens is large. Gullets frequently contain about 20 cubic centimeters, and the gizzard about 30 cubic centimeters, of material. Since the birds ordinarily feed slowly and deliberately, apparently selecting their food with great care, it is not surprising that their diet in favorable areas is varied. Stomachs have been examined that contained 29 kinds of food and more than 1,300 items ; stomachs rarely contain less than 13 kinds of food of 500 items. Mature birds evidently feed mostly on vegetation at all seasons, for the stomachs of 18 adults (table 6, p. 26) contained 88.28 percent of plant material and 11.72 percent of insects. Animal matter prob- ably ranks higher than plants in the diet of young birds, however, 26 NORTH AMERICAN FAUNA 57, PISH AND WILDLIFE SERVICE for the stomachs of 2 chicks and a juvenile (table 7, below) contained 88.5 percent of insects. The ratio of plant to animal food varies according to season (table 8, below), insects, for instance, apparently being eaten in greatest quantity in summer. Table 6. — Composition of the stomach ^ contents of 18 adult prairie chickens Item Stomachs in which found Quantity present Item Stomachs in which found Quantity present Number 18 12 16 5 6 Percent 88.^8 27. n 55.67 1.30 4.20 Animal matter Number 18 17 8 1 1 11 Percent 11 7i Leaves and stems Seeds and pods Insects: Adults 10 83 Buds and flowers Miscellaneous '. Eggs and larvae.. Round worms Prairie chicken feathers... Qrit . 0.89 1 Crops or gizzards, or both. ' M^oody pod septa, root stocks, and the like. 8 Trace. Table 7. — Composition of the stomach contents of three younff prairie chickens Item Stomachs in which found Quantity present Item Stomachs in which found Quantity present Vegetable matter Number 2 2 1 Percent 11.6 1.5 10.0 Animal matter Number 3 3 2 Percent 88. S Seeds or pods ... Insects: Adults 86.0 Eggs or larvae 2.5 Table 8. — Percentage of plant and animal food according to season Item Spring Summer Fall Winter Whole year Plants 94.25 5.75 71.0 29.0 85.8 14.2 95.0 5.0 86.51 13.49 Total .- 100. 00 100.0 100.0 100.0 100. 00 The data at hand indicate that Attwater's prairie chickens are preponderantly granivorous, for seeds and seed pods made up slightly more than 50 percent of all the material in the stomachs of 18 adults. Much succulent vegetation is eaten, however, including leaves, buds, flowers, and root stocks. The birds also consume insect eggs, larvae, and adults, as shown in tables 6 and 7. Parts of some 50 kinds of plants and more than 65 species of insects were identified in the food from stomachs or scats, or by observations in the field. The names of these plants and insects together with the seasons when they are known to be eaten, are listed in tables 9 and 10, pp. 27 and 28. ATTWATER'S PRAIRIE CHICKEN Taklb 9. — Plant foods (56) of AtHcater's prairie chicken 27 Plant Marsileaceae: Pepperwort (Marsilea) Poaceae: Paspalum (Paspalum ciliatifolium type) . - Bull grass {Paspalum boscianum ?) Paspalum (Paspalum plicatulum).. Panic grass (Panicum scribnerianum) Panic grass {Panicum spp.) -. Crabgrass {Digitaria) Sandbur {Cenchrus) Hegari {Sorghum vulgare) Rice {Oryza saliva) Corn {Zea mays).-. Cyperaceae: Beakrush (Rynchospora) Sedge {Carei)- Commelinaceae: Dayflower {Commelina cris- pa). Alliaceae: Wild onion {Nothoscordum bivalve)... Liliaceae: (Undetermined) Lcucojaceae: Stargrass {Hypoxis) Convallariaceae: Solomons seal {Polygonatum commulalum) . Ixiaceae: Blue-eyed-grass {Sisyrinchium va- rians). Polygonaceae: Dock (Rumex near crispus type), Ranuneulaceae: Buttercup {Ranunculus near hispidus) . Rosaceae: Dewberry {Rubv^) Malaceae: Chokeberry {Pyrus) Mimosaceae: Sensitive briar {Neptunia Lutea) Mimosa {Mimosa) -. Acacia {Acacia)... Cassiaceae: Partridge-pea {Chamaecri»ta fas- ciculaia) . Fabaceae: Wild pea (undet.) .-. Wild pea {Lathy ruspusillus).. Peanuts {Arachis hypogaea) Oxalidaceae: Woodsorrel {Oxalis) Euphorbiaceae: Doveweed(Cro Data from Texas Almanac and State Industrial Guide, pp. 231-236, The Dallas News, 1936. Pastubh Bubninq Unregulated prairie fires intentionally set or of accidental origin have been, and still are, common in coastal Texas in every month of ^ Figures supplied by David WinternLinn, Relow Land Company, Eagle Lake, Tex., from data compiled by the Rice Milling Association. 42 NORTH AMERICAN FAUNA 57, FISH AND WILDLIFE SERVICE the year. In Colorado and Austin Counties, for example, approxi- mately 80 percent of the best prairie chicken country was burned over in 1936. A fire of accidental inception ran over about 3,000 acres of the 6,700 acre J. C. Anderson Estate ranch, Harris County, in May 1937. The cover on about 3,000 acres of the best prairie chicken country in Matagorda County was intentionally burned in July 1937. Pasture burning is an annual event on the Pipkin ranch, Jefferson County, fires being started during first new moon after February 15. Areas that the first fires do not cover cleanly are subsequently treated, and burning generally continues well through the nesting season. Most ranchmen, however, complete pasture burning by March. The pastures are burned to remove old grass and encourage tender new growth more palatable to livestock. Fires usually are set when the grass is dry and the wind brisk, in order to finish the job quickly. The resulting fast, hot fires entirely denude areas except in low spots and deplete pastures of food, escape cover, and nesting sites. Prairie chickens and their natural enemies are crowded into unburned areas (pi. 12) and predation is undoubtedly intensified. During the breed- ing season fires destroy nests and probably many young birds as well ; no fewer than nine nests with charred eggs were found by Waddell in a 640-acre pasture burned in May 1936. Plant life recovers slowly in the absence of abundant rain; consequently, fires accentuate the results of drought. Altogether, fire is one of the most important factors limiting prairie chicken numbers in pastures. When burning is carried on as outlined under Management (pp. 53 to 54), however, the evils are greatly reduced or entirely eliminated, and benefits accrue to forage and soil as well. Overgrazing With the possible exception of Orange and Jefferson Counties, over- grazing is severe in most of coastal Texas from late in fall through early spring. In addition to reducing cover and food for prairie chickens (pi. 12), overgrazing probably also increases the vulnera- bility of the birds both to natural enemies and to man. In Colorado County from 1936 through 1938, for example, it was noted that marsh hawks and other raptors harried chickens more persistently in lightly vegetated pastures than in areas where heavy grassy cover was pres- ent. Waddell observed that hunters regularly kill a higher percent- age of known populations in areas where cover is light than where it is heavy. In Colorado County it has been found that the winter prairie chicken population of a pasture can be forecast with consider- able accuracy by observing the extent to which the area is grazed. Large winter populations are rare in pastures where cover is short. North American Fauna 57, Fish and Wildlife Service PLATE 12 B49778; B60059 Above, Excellent uiihurned cover at right of road; inferior burned cover at left; Colorado County, Tex., approximately 7 miles north of Eagle Lake, December 22, 1936. Below, Scanty cover where there has been overgrazing; the shrub is Cherokee rose {Ro.sn laerignla); Colorado County, Tex., 6 miles north of Eagle Lake, March 7, 1938. (Photos by V. W. Lehmann.) ATTWATER'S PRAIRIE CHICKEN 43 Aside from resulting unfavorably to prairie chickens, overgrazing in the gulf coastal country has been and is resulting in (1) the spread of undesirable brush and weeds, (2) the increase of needlegrass and other largely unpalatable grasses, and (3) serious erosion. An abun- dance of prairie chickens cannot be maintained on overgrazed tracts ; it is equally impossible to maintain forage and soil on such areas. Oil Development Oil development, which began with the discovery of the Spindle Top field in Jefferson County in 1901, has extended to every county in the coastal section. All the Attwater's prairie chicken area is classed as potential oil land, and almost every acre has been surveyed not once, but several times by oil crews. Veritable forests of oil der- ricks now stand in areas that once provided some of the finest prairie chicken range. In these areas, as in Fort Bend County, prairie chickens are almost, if not completely gone. Dkainagh Drainage canals, as in Brazoria and certain other coastal counties, have in some instances improved the territory within a mile or so of their margins by providing a permanent water supply where it was otherwise lacking during the summer months. On the other hand, drainage canals have doubtless decreased the general wildlife pro- ductivity of the counties in which they are situated by speeding up the run-off and thus lowering the water table. Until recently many prairie ponds retained water throughout the year, produced crappie, bream, and other edible fish, held safe nesting cover for black mallards and other water birds, grew an abundant supply of food for wintering waterfowl, and served as concentration points for prairie chickens during the heat of summer. Now they go dry during the slightest drought and produce virtually nothing. PASTtTRE Mowing Regular mowing of grassy areas, mainly for hay or increased forage production, has promoted a nearly pure stand of grass in some of the areas treated and has reduced shade and food, and the general attractiveness of the areas for prairie chickens and certain other valuable wildlife. In Colorado County, areas that have been mowed regularly for long periods are virtually game deserts; prairie chickens use them little even at nesting time. Pasture mowing in coastal Texas appears to be extending rapidly, and further reduction in wildlife resources may be expected from this cause unless definite 303807°— 41 4 44 NORTH AMERICAN FAUNA 57, FISH AND WILDLIFE SERVICE modifications are effected. Fortunately, the detrimental effects of pasture mowing to upland game birds may be mitigated, at least to some extent, by following management recommendations listed on page 66. Mechanical Accidents Prairie chickens sometimes fly into telephone wires, fences, and houses, or are struck by automobiles. In six instances in 1937 birds were noted as accidentally killed in the Eagle Lake section — as many as were recorded for predation. Mortality from accidents may be far more serious than is generally appreciated. Hunting Last, but not least, hunters certainly have contributed to prairie chicken decrease. Hunting has never been well regulated, and laws governing the taking of the birds have always been inadequate. Ac- cording to the Texas Game, Fish, and Oyster Commission (Ann. Kept., 1929: 86-91) prairie chickens had no legal protection until 1883, when a 5-month closed season was declared during the breeding period. In 1885, 148 counties claimed partial or total exemption to this and other regulations, and it was not until 1903 that the legislature passed a bill designating the months of November, December, and Jan- uary as the open season and setting a daily bag limit of 25. The legis- lation of 1908 was indeed a forward step, but there was no conserva- tion body to enforce the m.easure, local officers being depended on to carry out its provisions. The Game, Fish, and Oyster Commis- sion was not created mitil 1910, and for many years it was without adequate funds and personnel. As late as 1919 there were only 6 salaried wardens in Texas endeavoring to carry out, as best they might, almost wholly inadequate regulations. The law restricting the open season on prairie chickens to 4 days, September 1 to Sep- tember 4, inclusive, and the bag limit to 10 a day or 10 a season, was not passed until 1929. In 1937 there were only 9 full-time wardens in all the Attwater's prairie chicken country, and they were charged with patrolling more than 8 million acres ! Development of the coastal territory, as farming, grazing, and the exploiting of oil, crowded prairie chickens into ever smaller areas, where they were more easily found and killed. The Hug- the-Coast Highway (State Highway No. 35) and various other roads increased patrol problems; the intercoastal canal in Galveston, Cham- bers, and Jefferson Counties made formerly remote areas easily accessible to poachers. The number of hunters increased as trans- portation facilities and weapons were improved. The open season in September, normally a dry period (see pp. 57 to 68), did much to ATTWATER'S PRAIRIE CHICKEN 45 popularize hunting from automobiles. With these and other advan- tages, hmiters evidently harvested too closely. In the Bernard River country (western Austin County and northeastern Colorado Coimty), for example, it is known that in 1936 hunters killed 66 chickens, or 22 percent of the estimated total population (300). This was accom- plished despite the fact that the gunners were closely supervised and did not hunt in the most densely populated pastures. It is probable that excessive kills have occurred in other areas for many years; the 1937 census showed that Attwater's prairie chickens were nearly or completely extirpated except on or adjoining lands where they had been hunted little, if at all, for at least 10 years. In Harris, Galves- ton, Waller, and possibly in parts of other counties, hunting has probably been the agency most largely responsible for prairie chicken decline. MANAGEMENT Leopold (1931 : 3) has defined game management as the art of making land produce annual crops of wild game for recreational use. In coastal Texas, the management of prairie chickens must consist largely of the preservation of suitable grassland areas. Increased protection, habitat improvement, adequate predator control, and proper regulation of the harvest, hovvever, will greatly encourage recovery. PROTECTION An act (H. B. 30) passed by the State legislature, effective Sep- tember 24, 1937, forbade the killing of prairie chickens in Texas for a period of 5 years. This measure removes much of the pressure previously exerted on the birds during the regular open hunting sea- son, for true sportsmen will observe the decree. Landowners, game wardens, and other interested individuals, however, will remember that close seasons may tend to stimulate rather than retard the opera- tions of game bootleggers. According to the consensus of State game wardens in the coastal territory, violators are especially active (1) during the birds' spring courtship season when the conspicuous males, their instincts of self preservation dulled by the the mating urge, are easy targets for .22-caliber rifles; (2) late in July and August, when the tame young birds are of "frying" size; and (3) during the duck season, when whirring flocks of Attwater's prairie chickens evidently tempt gunners who have insufficient self control. Coastal game wardens report that, in years past, probably as many prairie chickens were illegally killed during the duck season as were taken legally during the then open season in September. The restora- tion of the species demands close protection for the remaining birds at all times. 46 NORTH AMERICAN FAUNA 5 7, FISH AND WILDLIFE SERVICE Although game wardens in the prairie chicken country are sin- cere and energetic, the territory is too vast for adequate protection under the facilities available. Sportsmen may render valuable aid by helping conservation officers apprehend irresponsible hunters, but landowners or their resident agents must handle the job if prairie chickens are to receive anything like adequate protection. Land- owners, individually or in groups, would do well to incorporate their holdings to form game-management areas, as advocated by the Ex- tension Service, Texas Agricultural and Mechanical College and the Texas, Game, Fish, and Oyster Commission. Under that plan, in- creased protection is provided through appropriate posting and provision by the landowners of qualified, resident, free-service State game wardens. Also technical service is given in solving predator problems, improving wildlife food and cover, properly regulating harvests, and otherwise maintaining wildlife crops. Nonresident owners should check up on the manner in which their foremen or lessees protect wildlife during their absence. It is regrettably true that some supposedly protected ranches are in reality hunting clubs for irresponsible agents and their friends when the landowners are away. Long-time lessees who wish to manage prairie chickens or other game should insist that their contract include control over the wildlife resources of the property as well as over grazing or other values. These lessees may thus avoid embarrassment from unwel- come hunter guests directed to the area by the absentee owners. Landowners who contemplate leasing their holdings for oil develop- ment might well follow the precedent set by a ranch owner in Refugio County. Each of his contracts carries the provision that the lease shall terminate immediately after any representative of the contract- ing company is caught on the property with a gun of any kind. Such a clause properly shifts the burden of supervising irresponsible oil workers from the landowner to the oil company. Increased protection of the few remaining Attwater's prairie chickens is necessary for success in management. Protection alone, however, is largely ineffective in areas where proper food and cover conditions are lacking. HABITAT IMPROVEMENT At present there are few areas in Texas where excellent conditions for prairie chickens prevail, and populations fluctuate markedly (table 15). Increase or decrease in study areas was thought fre- quently to coincide with fluctuations in the supplies of food, cover, or surface water. In many areas marked seasonal movements may be averted and larger and more stable populations maintained by removing deficiencies in habitat. ATTWATER'S PRAIRIE CHICKEN 47 Table 15. — Fluctuations in numbers of prairie chickens, Thomas and Koy pas- tures, Colorado County, 1937 Size Prairie chickens found Pasture Feb. 221 Apr. 13 May 2 June 2, 8, 10 July 26 Sept. 1 Oct. 22 Nov. 1 Thomas Acres 817 460 Num- ber 31 0 Num- ber 30 0 Num- ber 28 0 Num- ber 37 16 14 Num- ber 0 23 Num- ber 17 32 Num- ber 0 0 Num- ber 1 Koy - ... .- 0 1 Count of birds at or near the courtship grounds; no allowance made for any birds that may have been missed. All other counts were by the rope method. (See p. 49.) Evaluating Conditions In some instances it is relatively easy to point out one or more ways in which areas are inferior. Safe nesting cover is deficient in burned pastures that are devoid of old vegetation except in low damp places. Shade is insufficient on lands kept free of tall weeds or shrubs by mowing or grazing. Winter food, or cover, or both are usually lack- ing in areas having few native food-cover plants, as ragweed, goatweed (Croton), marsh-elder, or ruellia. Sometimes, however, habitat deficiencies are obscure and general observations of an infre- quent nature do not identify them. Accurate inventories are of assistance in determining (1) whether habitat improvement is needed, (2) what should be done, (3) results of work done, and (4) the sur- plus available for hunting. Management programs should be formu- lated on the basis of data obtained during inventories conducted thrice annually, in spring, summer, and winter. Inventory methods, recording and interpreting data, and management practices are dis- cussed in the following paragraphs. CBajsus Methods SPBING COUNT ON THE COURTSHIP GROUNDS The first census method that has been tried and found useful is the spring count of birds on the courtship grounds. Necessary are an automobile, preferably of light build and high clearance, a driver who is well acquainted with the area, and someone to act as observer, note keeper, and gate opener. A count is made on each courtship ground in the area, recording the number and sex of birds assembled there and the number and sex of birds seen between these grounds. The number of hens is recorded as a supplementary check. The number of males, increased 80 to 110 percent to allow for females that will be missed is accepted as the total population of the census area. For best results, the 48 NORTH AMERICAN FAUNA 5 7, FISH AND WILDLIFE SERVICE spring count is made in March from daybreak to about 7 : 30 a. m. A population estimate based on the maximum count obtained by reworking the same area three successive mornings, or often enough to offset variations due to unfavorable weather, is likely to be suffi- ciently accurate. Where recounts are impracticable, the single enu- meration should be made on a clear, quiet morning after a brisk norther. Courtship grounds may be located by sight or sound of the birds assembled there, but it is preferable to "drive out" the census area in belts 150 yards or less wide. Drumming grounds should not be ap- proached more closely than is necessary, because flushing the birds leads to inaccurate counts. As birds frequently squat, or freeze, at the approach of a car, it is desirable to wait at each occupied booming ground and refrain from counting until after vigorous courtship ac- tivity has been resumed. It is good policy to encircle a counted area completely before proceeding to a new site, for the fresh car tracks often assist in avoiding duplication. The accuracy of spring counts on the courtship grounds was tested in the following ways: (1) A section (640 acres) was covered on 10 successive mornings; (2) a 1,000-acre pasture was searched with the aid of 15 bird dogs; (3) a 1,000-acre pasture was recounted by 5 men using 2 cars, 3 horses, and 2 dogs ; (4) a section worked 3 successive days was rope counted. Spring counts have been made over ap- proximately 150,000 acres in Colorado, Wharton, and Austin Counties. These studies show that the enumeration of birds on the courtship grounds is the most rapid and economical of all known census tech- niques. More than 2,000 acres a morning have often been covered in areas having populations of about 1 bird per 45 acres. There are no indications that the method affects courtship activities adversely or that it greatly endangers early nesting. Also, the spring count of males is useful in yielding data on prairie chicken abundance in com- parable areas worked at nearly the same time and under nearly the same conditions. The spring count of birds on the courtship grounds, however, is not without its defects. Its accuracy is influenced by weather and other conditions at a time convenient for counting. Opportunity is limited to a few hours a day (from about 6 to 7 : 30 a. m.) over a short period (in March). The spring count does not reveal the number of females present, consequently, it does not produce reliable quantita- tive data on sex ratio and total population. Some observers experi- ence difficulty in distinguishing males from females, especially in the poor light of early morning. To them the analysis of sex differences, presented on p. 49, may be helpful. North American Fauna 57, Fish and Wildlife Service PLATE 13 V«if B49329; B489:9 Above, Rope counting uf prairie ctncl^ens on Matagorda Island, Tex., October 30, 1937. Below, Rope counting in myrtle bru.sh; Liberty County, Tex., approxi- mately 8 miles southeast of Devers, June 27, 1937. (Photos by W. P. Taylor.) ATTWATERS PRAIRIE CHICKEN 49 FIELD BASIS FOR DIFFERENTIATION OF THE SEXES IN SPRING Basis Males Females General color Light gray Brownish gray. Color of breast Not perceptibly different Much lighter than that from that of back. of back; appears al- most white in flight. Barring on back and Heavj^ black, well defined. _ Light, brownish black, breast. poorly defined. Color of head Orange - colored comblike Orange -colored combs structure present above absent. each eye. Feathers of crest Seldom erect Frequently erect. Neck Appears thick and heavy, Appears thin and long; with large, brightly col- air sac and neck tufts ored (orange) air sac rudimentary {%& inch apparent on each side of long). neck under prominent (2.25 to 2.90 inches) neck tufts. Size Large, heavy (about 2}Ob.)- Small, light (about 1% lb.). Action on courtship Bold, struts, fights, and Shy, does not strut, fight, grounds. booms in open cover. or boom. Flocking Usually in groups of 8 to 12 Usuallj^ alone. when booming, feeding, or resting at midday. Flushing Laborious take-off; cackles Easy take-off; usually when rising from ground. does not cackle. THE BOPE COUNT A second method of counting, one that has been tested with most encouraging results in the coastal prairie chicken country, is the rope count (pi. 13). Essential equipment includes two automobiles, preferably of light build and high clearance, an inch rope or a quarter-inch flexible steel cable 60 to 120. yards in length, and two strong swivels. An extra supply of water for radiators is needed in hot weather as cars heat up under the heavy going. In addition to drivers for the two cars, a third person should be taken along, if possible, to act as note keeper and general handy man. When the census area is reached, one swivel is attached to the right end of the rear bumper of the car in which the note keeper is to ride, and the second swivel is attached to the left end of the rear bumper of the other machine. Each end of the rope or cable is then securely tied to a swivel. Care must be exercised to see that the rope or cable, in turning, will tighten its twist and not loosen or unravel. One machine takes position parallel to a fence or other definite landmark while the other goes far enough way to stretch the rope so that only a slight bend remains. After both cars are in position, they drive over parallel courses at a uniform speed of 5 50 NORTH AMERICAN FAUNA 57, FISH AND WILDLIFE SERVICE to 15 miles an hour, which may be increased in light cover but which should be reduced in heavy vegetation to keep the rope, for the greater part of its length, about 5 inches above ground. Birds are tabulated as they are flushed. Those flying into uncovered ter- ritory are deducted when that area is dragged. When the end of a strip is reached, the car in which the note keeper rides turns and J^ Belts. En