1897.] LIZABDS OF THE GEHXTS SCELOPOBUS, 493 



Males are usually distinguished from females by the presence of 

 blue on the throat and on the sides of the belly ; but this character 

 should not be exclusively relied upon for distinguishing the sexes, 

 since a female from Presidio has the throat as blue as some males 

 collected at the same time in the same locality ; whilst, on the 

 other hand, an adult male specimen of the var. horrichis from 

 Puentillo de Acatan entirely agrees with normal females in the 

 coloration of the lower surfaces. The intensity of the blue varies 

 much, probably according to seasons. The male of the typical 

 ;S^. spinosus is described as with a blue throat striped with darker, 

 the sides of the belly blue, the breast and the middle line of the 

 belly white ; a large black blotch in front of the arm : such speci- 

 mens we possess from Guanajuato, Puebla, and Presidio (/. typica) 

 and from Ixtlan (var. liorridus). In S. horridus the blue of the 

 belly may extend on the anterior face of the thigh, as in our 

 specimen from N. oE Eio de Santiago, and in one from Mexico 

 referred by me to the var. darlii. The type of S. darhii is 

 described as with " a bluish abdomen, indistinctly black along the 

 middle region ; the lower surface of the head is blue, on the middle 

 region surrounded with black." This description might have been 

 penned from one of our specimens from Presidio, near Mazatlan, 

 and agrees well with the male from Fort Lowell which I regard as 

 a typical S. darlcii. Hallowell's S. magister has " two large bluish- 

 green blotches upon the abdomen, one on each side, and one upon 

 the neck ; the rest of the under surface light straw-yellow." Speci- 

 mens answering to this description I have only seen from Mexico 

 (/• typ^ca). Specimens from Arizona, referred to S. mcujister, have 

 the throat blue posteriorly, with a black cross-band, and the sides 

 of the belly of a deep blue edged with black within ; groin black. 

 Specimens (not full-grown) from Texas and Tampico have the 

 sides of the belly greenish blue and a small spot of the same colour 

 on each side of the throat. 



The systematic treatment of the Scelopori here grouped under 

 S. spinosus is a subject on which recent authors have shown great 

 divergence of opinion. 



In his Synopsis of 1885, Cope attaches undue importance to the 

 number of femoral pores, a character which he regards as " not 

 subject to such variations as to be embarrassing ; " and he forth- 

 with makes a bold primary division into species with 2-6 pores 

 and with 10 and more. The S. horridus (with 2-6 pores) is 

 therefore placed quite apart from 8. spinosus (believed to have 10 

 or more). This shows that the author cannot have counted the 

 pores in a \ ery large number of specimens, for the sei-ies in the 

 British Museum alone, which I daresay is far less important in 

 numbers than that to which he had access, contains not only speci- 

 mens with 7, 8, or 9 pores, which therefore would not fit in either 

 division of the synopsis, but there is even a specimen, from Guana- 

 juato, with 7 pores on one side and 10 on the other. S. darlcii, 

 usually accepted as a distinct species, or subspecies, by Cope and 

 other American authors, is not even mentioned in this synopsis, 

 ZooL. Soc— 1897, No, ZXXIII. 33 



