NATURAL SCIENCES OF PHILADELPHIA. 247 



the second row are also tipped with brown. There is a large brown spot on 

 each side of the neck, sometimes confluent with an elongate central one, which 

 extends to the occipital plates. A brown stripe passes from the eye to the neck 

 spot, entirely covering the last upper labial. Top of the head brownish grey, 

 indistinctly spotted with pale brown. Labial plate paler; frontals and rostral 

 ochreous. Beneath yellowish-white, immaculate. 



One specimen in the Academy, and nnmerous others in the National 

 Museum, Washington, received from Mr. John Xantus, from Cape St. Lucas, 

 California. 



101. H. chlorophaea nobis. Number of labials and rows of scales 

 the same as in the last species. The scales of the body are, however, more 

 elongate, and partly on this account are arranged in rows more oblique in an 

 antero-posterior direction. The vertical plate is a little broader, and the head 

 is narrower in proportion to its length. The body is rather more slender. 



The color is a greenish ash, much darker than in the preceding species. The 

 dorsal spots, instead of being brown, are black, and separated by intervals of 

 two scales in width. They are much smaller, occupying only the space from 

 the ninth to the thirteenth longitudinal rows, and are one scale and a half 

 long. They frequently divide and alternate, and their number on the body 

 amounts to from fifty-eight to sixty-six. Two rows of smaller alternating spots 

 appear on the sides, one upon the sixth and seventh rows of scales, the other 

 on the fourth. The distribution of colors on the head and neck is much as in 

 the last species, except that the neck spots are a little longer. The brown is, 

 however, replaced by black, and the ochreous by olivaceous. The crown and 

 muzzle are thickly punctulated with black. Beneath pale olivaceous. Gas- 

 trosteges 167, urosteges 55. Total length, 15 in. 6 1., of tail 2 in. 3 1. 



Two specimens from the National Museum, there received with others 

 from Fort Buchanan, Arizona, where they were collected by Mr. Irwin. 



Tachymenis Wiegmann. Type T. Peruviana. 

 Nova Acta, Acad. Caes. Leopold. Carol, xvii. 1834, p. 251. 



102. T. Chilensis Girard, U. S. Naval and Astronomical Exp. 1855, ii. 

 p. 213, Giinther, Cat. Brit. Mus. 1858, p. 34, Coronella Chilensis Schlegel. 

 Guichenot, Hist. Chili, ii. p. 79. Dipsas Chilensis Dum. & Bibr. vii. p. 1159. 



Var. near the third of Dum. & Bibr. 



Belly as in the ordinary variety, but the upper surface of the body of a light 

 rufous brown, more deeply shaded on the fourth and ninth rows of scales. 

 One specimen. Quinquina Id. Dr. Ruschenberger. 



Variety fourth, nobis. 



Coloration of the upper surface as usual, but upon each gastrostege there 

 is a single central, oblong, spot. These form a medial, unbroken, black band, 

 from near the chin to the anus. 

 One specimen. Talcahuano, Chili. Dr. Ruschenberger 



103. T. hypoconia nobis. The head of our single specimen is muti- 

 lated, hence a detailed description of the plating cannot be given. The shields 

 seem, however, to differ but little from those of the preceding species ; the pre- 

 frontals are relatively smaller, and the superciliaries larger. There are eight 

 superior labial shields, the eye resting on the fourth and fifth: the sixth and 

 seventh are disproportionately large. Nine inferior labials. Scales large, in 

 nineteen rows, the exposed part of those of the first row higher than long. 

 Body stout ; gastrosteges 140, one divided anal ; urosteges 52, relatively more 

 numerous than in T. Chilensis. 



Coloration. The upper surface of the head, body and tail, is of a wood 

 brown, many of the scales black at their bases. The first, second, third and 



I860.] 



