2cS0 Illinois State Lahoratonj of Natural History. 



No auteorbitals. Two postorbitals. Body moderately stout. 

 Head scarcely distinct from the body. 



Two internasal plates. With several longitudinal red stripes 

 above H. erythrogrammus. 



One internasal plate. Uniform blue black above. 



H. ABACURUtS. 



Hydrops erythrogrammus, Daudin. Red-lined Horned 

 Snake, Hoop Snake. 



Colnhtr erythroynunnnis. Daudin, Hist. Nat. Kept.. 1799, VII., 



p. 93, pi. 83! fig. 2. 

 Hellmps ernthnxjnniuniis, Holbr., N. A. Herp., 1842, III., p. 107, 



pi. 25.' 

 Ahdslor irriilhroiindinniis. Bd. and Gir., Cat. N. A. Kept., Pt. I., 



1853, p. 125. 

 l'(il<>iiisin(t ciythrniini iiniins, Dum.et Bibr., Erp. (n'-n., 1854, ^'I1.. 



p. 336. 

 Al>(ist<jr er>/t/iro(/r<niiiiiii.s. Davis and Kice, Bull. 111. State Lab. 



Nat. kist, I., No. 5, 1883, p. 32; Bull. Chicago Acad. Sci., 



1883. 

 ////'//•0/7.S- irijllu'xjntiiuiiiis,'^. (iarmau, ^Slem. Mas. Comp. Zocil., 



1883, pp. 35, 144. 



Body moderately stout. Head scarcely wider than the 

 neck, slightly depressed. Tail short. Dorsal scales smooth. 

 Rostral plate very wide. Two small internasals. Prefrontals 

 large, forming part of the anterior rim of the orbit. Frontal 

 plate hexagonal, its lateral margins nearly parallel, except 

 between the parietals. Supraciliaries large. One nasal plate, 

 grooved below the nostril. Loreal elongate, forming part of the 

 anterior rim of the orbit. No anteorbital. Two postorbitals, 

 the lower small. Supralabials seven, sixth largest. Infrala- 

 bials seven or eight, the fourth or fifth largest. Dorsal scales 

 in nineteen rows, all smooth and polished. Neutrals 107-1X5. 

 Subcaudals in 88-50 pairs. 



Color above bluish black, with five longitudinal red stripes. 

 Of these, one on each side occupies the two outer rows of scales, 

 excepting the bases of the scales of the inner row: three 

 scales above these stripes, on each side, is another, occuiM'iug but 

 one scale in width: while the fifth stripe occupies the median 

 dorsal row of scales. lieneath (.arneous, with round l)lack 



