Distribution in Tamaulipas.—Known only from Jaumave.
Only specimens from Jaumave are clearly R. f. griseoflavus; all others east of this locality are intergrades between griseoflavus and tropicalis, under which latter subspecies they are included. In griseoflavus the tail is longer in relation to the head and body, 141.2 (135-153) per cent, than in the other two subspecies that occur in Tamaulipas. The average weight of 14 males was 14 (12-16) grams.
Record of occurrence.—Specimens examined, 15, from Jaumave, 2400 ft.
Reithrodontomys fulvescens intermedius J. A. Allen
1895. Reithrodontomys mexicanus intermedius J. A. Allen, Bull. Amer. Mus. Nat. Hist., 7:136, May 21, type from Brownsville, Cameron Co., Texas.
1914. Reithrodontomys fulvescens intermedius, A. H. Howell, N. Amer. Fauna, 36:47, June 5.
Distribution in Tamaulipas.—Northern half of state.
No specimen of this subspecies has been examined. Jones and Anderson (1958:447) reported specimens from Rancho Pano Ayuctle as R. f. intermedius, but here those same specimens are assigned to R. f. tropicalis. J. A. Allen (1891:223) recorded specimens from Santa Teresa as Ochetodon mexicanus. According to Hooper (1952:142) that name was used by Allen for R. fulvescens. Allen's specimens from Santa Teresa are here referred to R. f. intermedius on geographic grounds.
Records (Hooper, 1952:108): Camargo, 200 ft.; 20 mi. S Reynosa, Charco Escondido; Matamoros, 30 ft.; 7.5 mi. S Matamoros; 29 mi. S Cd. Victoria, 800 ft.; Hacienda Santa Engracia, 800 ft.; Santa Teresa (50 mi. SW Matamoros); Sierra San Carlos (El Mulato, Tamaulipeca, 1500 ft.).