IJf. Proceedings of the Biological Society of Washington. 



tunnelling inwards, leaving only an empty shell. At present they cause 

 serious damage to sugarcane in the big plantations around Okeechobee 

 Lake, where they often become very numerous and where hundreds are 

 killed by the use of strychnine bait. 



These rats are partly diurnal, being frequently seen running about in 

 daytime in grassy situations or even crossing the highways. 



Specimens examined. — Total number, 155, irom the following localities 

 in Florida: Canal Point, 4; Canaveral, 2; Chester Shoal, 1; Citrus 

 Center, 1; Eden (St. Lucie County), 1; Kissimmee, 44; Kissimmee 

 River (Osceola County), 4; Labelle, 2; Lake Harney, 33; Lake Kissimmee, 

 2; Lake Mobley (Hillsborough County), 1; MuUett Lake (Orange County, 

 2; Ocala National Forest, 5; Okeechobee, 2; Ponce Park, 1; Port Mayaca, 

 5; Port Richey, 6; Ritta, 9; Sebastian, 9; Sebring, 1; Silver Springs, 2; 

 Sunbeam (near Titusville), 1; Titusville, 15; and Wilson, 2. 



Sigmodon hispidus insulicola, new subspecies. 



INSULAR COTTON EAT. 



Type. — Collected on Captiva Island, Florida, February 25, 1939, by 

 W. H. Osgood; male adult, skin and skull. No. 48679, Field Museum of 

 Natural History; original number 7057. 



Range. — Captiva Island, Sanibel Island, Chadwick Beach (near 

 Englewood). 



External characters. — Upper parts paler and more grayish (less blackish) 

 than in floridanus from the central portion of Florida; under parts more 

 whitish; tail averaging paler both above and below; hind feet averaging 

 paler; size smaller. Compared with spadicipygus from Cape Sable it is 

 about the same size, but colors much paler and more grayish (less 

 brownish). Compared with littoralis from the east coast beaches, 

 opposite Micco, it is smaller, more grayish on the upper parts and more 

 whitish (less buflfy) beneath. Compared with exsputus from the Lower 

 Florida Keys insulicola is decidedly more grayish, lacking the strong 

 buffy suffusion on the upper parts shown by exsputus. The underfur 

 is of a darker shade of neutral gray. 



Cranial characters. — Skull much smaller and relatively shorter than 

 that of littoralis or floridanus; similar in size to that of spadicipygus. 



Color. — Type: Hairs of upper parts tipped with buffy white over dark 

 neutral gray underfur, producing a grayish effect; rump shows a stronger 

 suffusion of pale buff; sides pale pinkish buff; feet grayish white; tail 

 hair brown above, whitish beneath; under parts creamy white. 



Some specimens from Sanibel Island are slightly more suffused with 

 buff on the back and sides, but all are paler than in floridanus. 



Measurements. — Type (male adult): Total length, 274; tail vertebrae, 

 117; hind foot, 31. Average of 6 adult males, from Sanibel Island (5), 

 and Captiva Island (1): 278; 114; 31.7. Skull: Average of 4 adult 

 males from same localities: Occipitonasal length, 35.9 (35.2-36.9); 

 zygomatic breadth, 20.3 (20-21); cranial breadth, 15.6 (15.1-15.6); 

 length of nasals, 14.3 (14-14.9); maxillary tooth row, 6.7 (6.7-7). 



Remarks, — The range of this pale, gray race of the cotton rat is not 



