1030 



REPORT OF NATIONAL MUSEUM, 1898. 



known from the valley of Mexico. I took three specimens at the lake 

 of Xochimilco and at Chapultepec, and Dr. Duges sent me a fourth 

 from Guanajuato. Mr. Bocourt sent a fifth from some part of Mexico to 

 the National Museum. These all differ from the type of E. mavro.stemma, 

 which is also from the valley of Mexico, in the general indistinctness 

 of their markings and in the absence of the parietal spots. On loss 

 of the epidermis the markings come out, except the parietal spots. 



This is a water snake in its habits, but spends much of its time on 

 the banks. My friend, Mr. Julius Flohr, of the City of Mexico, took 

 me ou a boating excursion on the lake of Xochimilco, near that city, 



and I had the opportunity 

 of observing the habits of 

 this snake and of compar- 

 ing them with those of the 

 U. melanogaster, which in- 

 habits the same locality. 

 On being disturbed, the E. 

 macrostemma plunges into 

 the water, but does not go 

 far beneath the surface, 

 but takes refuge under 

 the edge of the bank, or 

 emerges in a new spot, so 

 that it is not difficult of 

 capture. When a p - 

 proached or caught it is 

 very pugnacious. The 

 habits of the E. melano- 

 gaster are different. It, too, lies on the bank, but when it plunges it 

 dives to the bottom and so effectually conceals itself that it can not be 

 captured on that occasion. When caught it is much less i)ugnacious 

 than the E. macrostemma. The columns that support the aqueduct 

 that carries water from Chapultepec to the City of Mexico are covered 

 with a dense vegetation, which is continuously watered by leaks in the 

 venerable structure. On examining this vegetation at my height above 

 the ground, I encountered in the thick of it a round eye. Exposure 

 revealed first the head and then the body of a snake of this species, 

 which found a congenial abode in that position. 



This is the species which appears on the arms of Mexico. Tradition 

 states that Cortes adopted the arms after observing an esigle {Poly- 

 horns) sieze a water snake and carry it to a large cactus {Opuntia) iu 

 its talons.^ 



I have seen this brightly colored form from Guanajuato (Duges) ; Mex- 

 ico ( Hoeje), and Vera Cruz (Sartorius and the Geographical Commission). 



Fig. 280. 



Eut-*;nia macrostemma macrostemma Kennicott. 



— 1. 



Valley of Mexico. 



Cat. No. 7247, U.S.N.M. 



' Eiitwtiia flavilahris Cope, Proc. Acad. Nat. Sci. Pbila., 1866, p. 306; Proc. Amer. 

 Phil. Soc, 1884, p. 173. 



