North American Fauna No. 55. U. S. Dept. of Agriculture. Biological Survey 



REAR VIEW OF YELLOW-HAIRED PORCUPINE. 



When alarmed the porcupine draws the skin of its back forward and exposes the armor of quills from tip 

 of tail to eyebrows (photograph by C. Hart Merriam, in Tuolumne Meadows, Calif.). 



