402 



BULLETIN 56, UNITED STATES NATIONAL MUSEUM. 



The following is Doctor Allen's description of this subspecies, which 

 is known only from the type series : 



Adult. — Above grayish brown, with a slight yellowish wash, mostly confined to the sides, 

 strongly varied with dull blackish brown, especially along the median line, often forming a 

 distinct broad blackish dorsal band; below clear grayish white, the tips of the hairs being 

 white and the basal portion plumbeous; ears blackish brown, narrowly edged with white; 

 tail sharply bicolor, upper third of its circumference blackish brown, rest white; feet white, 

 with a faint buffy tinge. 



Young. — Dull gray brown (dark "mouse-gray") above, with a darker (blackish) median 

 band; otherwise like the adult. 



Measurements. — Male (type): Total length, 127; tail vertebrae, 52; hind foot, 16; ear 

 (from dry skin), 11. 



Nine adult males measure as follows: Total length, 126 (121-130); tail vertebra", 51 

 (50-52); hind foot, 16 (1.5-17). 



A single adult female is larger than the largest male of the series. 



Type, No. \li\i, male adult, San Antonio, Texas, February 7, 1896; H. P. Attwater. 



This subspecies is based on a series of 10 adults and 7 two-thirds grown young, all winter 

 specimens (December 14-March 19), taken mostly in January and February. 



They are so different in color and size from a large series of Peromyscns michiganensis from 

 Fort Snelling, Minnesota, collected by Doctor Mearns, that they would seem to be specifi- 

 cally distinct, were it not that a large series of winter specimens from Lawrence, Kansas, col- 

 lected by Prof. L. L. Dyche, are so nearly intermediate in both size and coloration as to 

 render it probable that P. m. pallescens is merely a pale, depauperate form of P. michi- 

 ganen.fis. 



The measurements of a series of adults from each locality compare as follows: 



Locality. 



Fort Snelling 



lyawrcncc 



San Antonio. 



3 males . . 

 5 females 

 10 males . 

 5 females 

 9 males . . 



Total length. 



mm. 

 143 (144-146) 

 149 (144-153) 

 137 (130-149) 

 146 (137-153) 

 126 (121-135) 



Tail verte- 

 brae. 



mm. 



56 (55-59) 



57 (54-63) 

 51 (43-58) 

 57 (55-63) 

 51 (50-52) 



Hindfoot. 



mm. 

 17.3 (17-18) 

 18.1 (18-18.5) 

 17.9 (16-19) 

 18.0 (16-19) 

 16.0 (14-17) 



The Kansas specimens are thus good intergrades, and are almost distinct enough to merit 

 recognition in nomenclature. They are rather nearer the Fort Snelling series than the San 

 Antonio series. 



In coloration P. m. paMescens bears a close general resemblance to Peromyscns canus 

 Mearns from the same locality, but can be readily distinguished by its relatively shorter tail 

 and hind foot and much smaller size. (Bull. Am. Mus. Nat. Hist., VIII, 1896, p. 238.) 



Subgenus PEROMYSCUS. 

 WOOD MICE. 



Onychomys and Baiomys, formerly subgenera of the old genus 

 Peromyscus, are regarded here as distinct genera. Merriam erected 

 the subgenus Megadontomys in 1898, and Osgood the subgenus 

 Haplom'ylomys in 1904, leaving a complex assemblage of forms to 

 represent the subgenus Peromyscus, which is susceptible of further 

 subdivision. Associated with typical leucopus are a number of forms, 

 including mearnsii, texanus, tornillo, and arizonse on the Mexican 



