450 PROCEEDINGS OF THE NATIONAL MUSEUM VOL.88 



postoculars 2-2; the temporals are 2-2 except on both sides of two 

 and on one side of two others, which have 2-3. Other data are given 

 in table 24. 



♦MASTICOPHIS TAENIATUS TAENIATUS (Hallowell) 



A single Mexican specimen (No 46594) in the Museum is from 

 Lake Santa Maria, Chihuahua. 



MASTICOPHIS TAENIATUS AUSTRALIS Smith 



MasticopMs taeniatus australis Smith, Journ. Washington Acad. Sci., vol. 31, pp. 

 390-392, 1941. 



One specimen was secured, at Tacicuaro, Michoacan (No. 111312). 

 The Museum has one other, the type (No. 10240), from Guanajuato. 



The adults of this race still remain somewhat dubious. A series 

 of specimens from Alvarez, San Luis Potosi, recently examined, is 

 of considerable interest (Mus. Comp. Zool. Nos. 19027-31, 19552-3, 

 24999-25001). There are four juveniles that are identical with the 

 type series of australis; there is one juvenile typical of ruthveni 

 (lacking lateral stripe) ; and one juvenile is about intermediate be- 

 tween the two color patterns; all are of about the same size. There 

 are three adults, all typical ruthveni. Thus one is faced with these 

 possibilities: Either ruthveni normally has two types of patterns in 

 the young — some very distinctly striped and some unicolor as in the 

 adults — or the Alvarez population is an intergrading one between 

 typical ruthveni of the coast and another plateau race, presumably 

 -australis. Unfortunately, there are no considerable series of speci- 

 mens from areas in which ruthveni might be considered typical; 

 practically all specimens are from southern Texas, where intergrada- 

 tion with schotti occurs, or from the plateau in San Luis Potosi, 

 where intergradation with australis may be indicated. Thus it is not 

 assured that two patterns do not normally occur in the young. Never- 

 theless, for the present such an assumption — an unusual one — is not 

 necessary. A more reasonable assumption is that on the plateau the 

 young are striped (such specimens = australis), while on the coast 

 they are unicolor and like the adults (= ruthveni) ; the adults of 

 both forms are unicolor and practically indistinguishable. Thus the 

 specimen from Zamora, Michoacan, referred by me {op. cit., p. 393) 

 to ruthveni seems more properly associated with australis, a disposi- 

 tion in keeping with geographical facts and in support of the present 

 theory. While specimens now known are insufficient to assure its 

 accuracy, they do support the premise that two races of unicolored 

 adults occur on the plains of the southern part of the plateau and on 

 the coast from Texas to San Luis Potosi; one {ruthveni) has uni- 



