VARIATIONS OF GAETEK-SNAKES. 173 



when fresh specimens shall be available from this region. At present 

 we can only say that the forms are undoubtedly closely related, and 

 belong to the same group.'* In the northwest parietalis meets another 

 form (concinnus), with which it is closely allied. The relationship of 

 these forms will next be discussed. 



CONCINNUS b 



Description. — Doctor Hallo well (l.So2, 1S3), in his description of 

 this form, concludes with the remark that it is "The most beautiful of 

 the North American serpents hitherto discovered." His enthusiasm 

 is easily realized by anyone who has the good fortune to see living 

 specimens. The form differs from parietalis only in the increased 

 amount of black pigment and the attendant effect upon the pattern. 

 The dorsal scales, mcludmg the first row, are generally black, with the 

 exception of more or less of the scales involved in the interspaces, 

 which are red. The stripes may be brightly colored, but are usually 

 yellowish, greenish, or bluish. The lateral when present is on the 

 second and third scale rows, but is frequently absent; the dorsal is 

 generally confined to the median row, but may also cover tlie halves 

 of adjacent rows or be entirely obsolete. The spots when distinct 

 are arranged as in parietalis, i. e., those of the upper row fused, those 

 of the first row distinct from each other but fused with the upper 

 row. The interspaces (always red) are, when present, however, 

 generally much narrower (being only one-half to one-fourth a scale 

 wide) than in parietalis and are frequently entirely absent, the skin 

 being solid black. Belly usually dark greenish or bluish, and gener- 

 ally much speckled with black and occasionally orange. 



It will be seen from the above description that there is no character 

 which will constantly distinguish specimens of concinnus from parie- 

 talis. The narrow dorsal stripe and lateral interspaces of the former 

 will usually do so, but these may be exactly as in parietalis. Still, the 

 fact that nearly all specimens from Washington and northern Oregon, 

 west of the Cascade range, are characterized by a marked predomi- 

 nance of black pigment and a narrow dorsal stripe justifies their 

 recognition as a separate form. 



Hahits and liahitat relations. — As far as I know very little has been 

 recorded on the habits of this snake. Cooper and Suckley (1860, 297) 

 record the following notes: 



This species exists in great abundance near Steilacoon and Nisqually. They are 

 found on the gravelly prairies and in the vicinity of the numerous small lakes of this 

 section of country. About the lirst of April they begin to come out of winter 



« It is interesting to note that the three forms, eques, parietalis, and sirtalis, all exhibit 

 the occasional tendency toward th(> fusion of the first few anterior spots into cross-bars. 



b Thamnophis sirtalis concinyiiis (Hallowell), Proc. Acad. Nat. Sci. Phila., 1852 

 pp. 182-183. Includes Erdienia pickcringi Baird and Girard, E. sirtalis trilincuta 

 Cope (part), E. sirtalis tetrataenia Cope (part). 



