TRIMORPHODON.—DIPSAS. 175 
According to Cope, this snake is known by the name of “culebra casera” in 
Tehuantepec. 
2. Trimorphodon upsilon. 
Trimorphodon upsilon, Cope, Proc. Am, Phil. Soc. 1869, p. 152. 
Eteirodipsas biscutata, Jan, Iconogr. Ophid. xxxix. t. 1. fig. 3. 
Hab. Mexico, Chibuahua, Guadalajara, Zacualtipan (Cope), Ventanas in Durango 
(forrer), Guanajuato (Dugés), La Cumbre de los Arrastrados (A. C. Buller), Jalapa 
(Hoge). 
An uninterrupted white or whitish collar across the neck. Scales in 23-24 series. 
Upper labials generally eight. 
DIPSAS *. 
Dipsas, sp., Boie, Isis, 1827, p. 549. 
1. Dipsas cenchoa. 
Coluber cenchoa, Linn. Syst. Nat. i. p. 389. 
Dipsas cenchoa, Wied, Beitr. Reise Brasil. i. p. 396; Giinth. Cat. Col. Sn. p. 174; Salv. P. Z. S. 
1860, p. 457 ; Cope, Bull. U. S. Nat. Mus. no. 32, p. 68. 
Imantodes cenchoa, Dum. & Bibr. Erpét. vii. p. 1065. 
Dipsas weigelit (Fitz.), Schleg. Ess. ii. p. 278, t. 11. figg. 19, 20. 
Himantodes leucomelas, Cope, Proc. Ac. N. Se. Phil. 1861, p. 296. 
flab. Mexico, Jalapa and Huatusco in Vera Cruz (Godman), '‘Teapa in Tabasco 
(H. H. Smith); Guatemata, Coban (Salvin); Costa Rica, Irazu (fogers); PANAMA 
(Mus. Brit.), Chiriqui (Champion).—TRopicaL SoutH AMERICA. 
The specimens referred by me to this species vary in their scutellation and coloration. 
Males seem to have larger eyes than females. Lhe preorbitals, variable in number, may 
or may not touch the vertical ; the upper labials are eight or nine in number ; frequently 
two temporals are in contact with the postoculars, but almost as frequently these two 
anterior temporals coalesce into a single shield. Thus the great width of the median 
dorsal scales remains the principal distinctive character of this species. 
2. Dipsas gemmistrata. 
Dipsas cenchoa, Cope, Proc. Ac. .N. Sc. Phil. 1860, p. 264 (nec Linn.). 
Himantodes cenchoa, var. elegans, Jan, Iconogr. Ophid. xxxviii. t. 2. 
Himantodes gemmistratus, Cope, Proc. Ac. N. Sc. Phil. 1861, p. 296. 
Dipsas gemmistrata, Cope, Bull. U. S. Nat. Mus. no. 32, p. 68. 
* T strongly suspect that Leptognathus stratissuma, Cope, Proc. Am. Phil. Soc. xxiii. p. 280 (1885), from 
Panama, will prove to be a species of this genus. 
