146 



BULLETIN 114, UK^ITED STATES NATIONAL MUSEUM. 



The black tips on the red scales are exceedingly variable. Nearly 

 all individuals show them to some degree, but they are absent in a 

 few. The latter is true of a specimxcn from Chiapas and of another 

 from Guatemala. The black tips on the yellow scales are often 

 accompanied by a dark mottling of the rest of the scale. This is 

 rarely excessive. Occasional specimens show no black on the yellow 

 scales. Vera Cruz specimens show no approach to annulata, and the 

 relationship to nelsoni can not be told for lack of specimens. The 

 two examples from Costa Kica show no approach in black spotting 

 of the yellow rings to micropJiolis. 



The narrowness and uniform width of the yellow wings characterizes 

 annulata and nelsoni as well as 'polyzona, and is probably evidence of 

 relationship. The two Costa Eican specimens both have these rings 





do 



^wm^M 







Fig, 45.— Map showing locality records for Lampropeltis polyzona. 



very narrow. The transition to micwpholis is shown by a specimen 

 from Panama and one from Darien, both of which have the 3'ellow 

 rings wider than in polyzona but decidedly narrower than Ecuadorean 

 examples of micropJiolis. These have the scales of the yellow rings 

 strongly black-tipped but less so than is typical of the latter form. 



Affinities. — That all the Mexican and Central American represen- 

 tatives of the triangulum group are closely related hardly needs 

 argument. It has not been doubted. The difficulty has lain in 

 correctly defining the several forms and determming just what the 

 relation ol each to each is. The evidence from variation and geo- 

 graphic probabilities is that polyzona is directly related to micwpholis 

 and that it is distinct from annulata on the Gulf side of Mexico. The 

 nature of its relationship to nelsoni, on the Pacific side of Mexico, 

 must be learned at a future date. 



