1156 



REPORT OF NATIONAL MUSEUM, 1898. 



most dangerous species of that region, wliere it is known as the "black 

 tail." 



Near Lake Valley, soutlieru New Mexico, I killed a fine specimen of 

 this species, which I discovered in the act of springing through a bush. 

 When I struck it, it was suspended over a branch, looking at me. It 

 was heavy in its movements, except at the moment of leaping. 



CrotaJus moIo8sus Ba'trd and Girard. 



Locality. 



Southern Arizona 



Sonora, Mexico 



Pecos ' liiver, Texas 



Fort Iluacliuca, Arizona. . 



do 



Mexican boundary line . .. 

 Tucson Mountains, Tuma 

 County, Arizona. 



. Wlien 

 collected. 



Oct. — , 1873 



From whom received. 



n. W. Hcushaw 



Col.J. I».Graham,U.S.A 



Dr. A. L. Hecrmau 



Dr. T.Wilcox 



do 



Dr. E. A. Mearus 



do 



Nature of 

 specimen. 



Alcoholic. 



do. 



do. 



do. 



do. 

 Skin. 

 Alcoholic. 



CROTALUS BASILISCUS Cope. 



Crotalus hasilisrus Copk, Proc. Amer. Phil. Soc, XXII, 188.5, p. 180. — Duges, Natu- 



raleza (2), I, 1888, p. 133.— Cope, Proc. U. S. Nat. Mns., XIV, 1892, p. 688. . 

 Caudisona hasilisva Cope, Proc. Acad. Nat. Sci. Phila., 1864, p. 166; 1866, p. 308. 

 ■ Crotalus rhombifer DuGi:s, Natnraleza, IV, 1877, p. 22. (Not of Latreille). 

 Crotalus terrificm Boulenger, part. Cat. Snakes Erit. Miis., Ill, 1896, p. 574. 



Two pairs of symmetrical muzzle plates in contact ; third, or posterior, 

 l)air subdivided. Eostral subtriangular, liigher than wide, in immedi- 

 ate contact with nasals and frontals. Oblique length of postnasal equal 

 horizontal length of prenasal; latter separated by small scales from the 

 anterior labials. Fourteen superior labials, separated from the subor- 

 bital series by two and three rows of scales. Three Hat plates between 

 the elongate, flat superciliaries. Temporals smooth. Scales in twenty- 

 nine rows, external largest, and with two next on each side smooth. 

 Tail stout, surrounded by thirteen longitudinal rows at the middle. 

 Rattle very acuminate, with a lateral groove. Gastrosteges, one hundred 

 and ninety-nine; urosteges, twenty single, four terminal divided. End 

 of muzzle to rictus, 35 mm.; to vent, 1,11(5 mm.; vent to base of rattle, 

 77 mm. 



Ground color pale-yellowish brown, much replaced by the following 

 markings, which are on entire scales, not parts: about thirty dorsal 

 rhombs from a short distance posterior to head to opposite vent, of a 

 bright chestnut red, browner medially and white bordered, five scales 

 long and fourteen wide inside the white border, on the median part of 

 the body, where they are in contact. Posteriorly they are separated, 

 anteriorly elongate. Laterally, between each two rhombs a spot of 

 bright chestnut. Belly and inferior scales yellow, every second or third 

 lateral one the base of a short oblique chestnut band. Head dark brown ; 

 two elongate o(;cipital spots. Superior labials yellowish. A narrow 



