44 BTJLLETIlsr 99, UK^ITED STATES NATIONAL MUSEUM. 



between sexes in T. naivashae, but the largest males fall far short of 

 the dimensions given for the type skull of annedens. 



Skins of females from Naivasha Station average darker than females 

 from the south end of Lake Naivasha. Only one blackish skin is 

 present in the largo series of naivashx examined; the color is very 

 uniform throughout the lot, except for the usual sexual difference, 

 females averaging noticeably darker than males. 



Loring furnished the following notes on this species for African 

 Game Trails : ^ 



Some 15 miles west of Lake Naivasha mole rats became com mon, and on the sandy- 

 flats within 5 miles of the lake they were so abundant that our horses broke into 

 their runways nearly every step. Tlieir underground tunnels and the mounds of 

 earth that were thrown out were similar to those made by the pocket gophers of the 

 western United States. Many were snared by the porters and brought to camp alive. 

 They would crawl about slowly, not attempting to run away, but looking for a hole 

 o enter. After the lapse of a few seconds they would begin to dig. In any slight 

 ■depression they began work, and when small roots of a tussock of grass intervened, 

 they used their teeth until the ol^struction was removed, and then with the nails of 

 their front feet only, continued digging. As the hole deej^ened they threw the dirt 

 •out between their hind legs and with them still further beyond. After the earth 

 had accumulated so that it drifted back they faced about, and using their chest as a 

 scoop, pushed it entii-ely out of the way. They were most active in the evening, 

 at night, and in early morning. Several were found dead near their holes, ha\-ing 

 evident!)- been killed by owls or small cai-nivorous mammals. 



TACHYORYCTES IBEANUS Thomas, 



1900. Tachyoryctes splendens ibeanus Thomas, Proc. Zool. Soc. London, 1900, 

 p. 179. June 1. (Machakos, British East Africa; type in British 

 Museum.) 



1910. Tachyoryctes splendens ibemius Roosevelt, African Game Trails, Amer. 

 ed., pp. 473, 479; London ed., pp. 485, 490. 



Specimens. — Fifty-five, as follows: 



British East Africa: Kyambu, 3 native skins (Loring); Nairobi, 

 52, including 13 in alcohol (Mearns, Loring.) 



This species shows the maximum difference in color between adult 

 males and females; the females are very much darker. Several skins 

 have large, irregular white blotches on the underparts. Very young 

 specimens are usually entirely black. 



tachyoryctes D.^MON Thomas. 



1892. Rhizowys splendens True, Proc. U. S. Nat. Mus., vol. 15, p. 464. (Not of 



Riippell.) 

 ] 909. Tachyoryctes dnwon Thomas, Ann. and Mag. Nat. Hist., ser. 8, vol. 4, p. 545. 



December. (Mount Kilimanjaro, East Africa, 5,000 feet; type in British 



Museum.) 



Specimens. — Seven, as follows: 



German East Africa: Marangu, Mount Kilimanjaro, 6 (Abbott); 

 Mount Kilimanjaro, 5,000 feet, 1 (Abbott). 



I Roosevelt, African Game Trails, Appendix C, p. 485. 1910. 



