124 Merridrii — Four JVt'ir Grasshopper Mice. 



Onychomys torridus yakiensis subsp. nov. 



Tape from Camoa, Rio Mayo, southern Sonora, Mexico. Adult female, 

 No. 95,855, U. S. National Museum, Biological Survey Colle(;tion. Oct. 28, 

 1898. E. A. Goldman. Orig. No. 13,158. 



Charactevf!. — Color similar to that of Onychomys torridax ramona, but size 

 slightly larger (hind foot averaging 22.5 instead of 20.5). Median dorsal 

 area, from crown to base of tail, usually much darker than sides of V)ack. 

 Compared with torridus, longicaudus, and ramona, the molar teeth, particu- 

 larly the anterior molars, are broader and heavier, and the palate usually 

 ends posteriorly in a median projection — in torridus and ramona it is 

 concave. 



Measurements. — Type specimen: Total length, 154; tail vertebrae, 53 ; 

 hind foot, 22. Average of 6 specimens from type region : Total length, 149; 

 tail vertebne, 53 ; hind foot, 22.5. 



Remarks. — Onycimmjis i/akiensis has the dark head, large ears, and general 

 coloration of ramona, in which i-espects it difiers from typical torridus. Its 

 range appears to he western Sonora and northern Sinaloa, and may join 

 that of ramona around the head of the Gulf of California. The collection 

 of the Biological Survey contains 19 specimens of this form from Camoa 

 and Alamos, Sonora, and Sinaloa, Sinaloa. The series comprises both 

 pelages (grayish brown and dull fulvous) and various ages. The young 

 wiien half grown are dark gray like those of ramona; when nearly full 

 grown they are pale smoke gray, much paler than ramona of correspond- 



Onychomys torridus canus subsp. nov. 



Ti/jK' from San Juan Capistrano, Zacatecas, Mexico. Adult female, 

 No. 90,843, U. S. National Museum, Biological Survey Collection. Aug. 23, 

 1897. E. W. Nelson and E. A. Goldman. Orig. No. 11,574. 



Characters. — Similar to torridus in general characters, but tail and ears 

 longer, and color drab gray or grayish clay-color instead of fulvous. 



Measure)nerds. — Type specimen: Total length, 152; tail vertebrae, 55; 

 hind foot, 22. Average of 5 specimens from type locality : Total length, 

 150 ; tail, 54 ; hind foot, 22. 



Remarks. — In addition to the Zacatecas specimens, others are at hand 

 from Rio Verde and Jesus Maria, San Luis Potosi. 



Onychomys leucogaster albescens subsp. nov. 



Type from Samalayuca, Chihuahua, Mexico. Adult female, No. 50,040, 

 U. S. National Museum, Biological Survey Collection. Dec. 12, 1892. 

 C. P. Streator. Orig. No. 2399. 



Ciiaracters. — Size large. Similar to 0. leucogaster pallescens from Hopi 

 Pueblos of Arizona, but much paler, and with cheeks and thighs snowy- 



