Isotely and Coralsnakes. 



15 



Elaps 



Opisthoglyph 



Aglyph 



"i *■ 



Homalocranium 

 rubrum 



Streptophorus atratus 



fidvius var. 

 affinis 

 CaUophis 



Erythrolamprus 

 aesculapn var. 

 venustissima L. 



Streptopliorus atratus 

 Coronella micropiholisE. 



fidvius 

 CaUophis 

 macclellandi 



Coronella micropholis 

 Geophis seniidoliata 

 Urotheca elapoides 

 Rhinorhilus 



fidvius typic. 

 cora llinus 

 hiickleyi 

 i'uryxanthus 

 CaUophis 



Erythrolamprus 



aesculapii 

 Scolecophis 



aemula 



Streptophorus atratus 

 Polyodontophis 

 venustissimus 



Homalocranium 

 niichoacanum 



Erythrolamprus 

 aesculapii 



Coronella doliata 

 Coronella micropholis 

 Atractus latifrons 

 Cemophora coccinea 

 Urotlieca elapoides 



Coronella doliata 

 Coronella microphol. 

 C. pyromelanus s. zonat. 

 Urotheca 



fulvius 

 surinamensis 

 marcgravi 

 leniniscatus 



Urotheca ehqmides 



decoratus 



cleyans 



filiformis 



Tail of: 

 E. fidvius 

 E. eury- 

 xanfhus 

 E. corallinus 



Erthrolamprus 

 aesculapii, 

 var. 



Tropiidodipsas 

 Coronella microphol. 

 Tail of: C. microphol. 

 and C. zonatus 



Diagram s No. III. 



Table showing instances of Isotely in Patt er n and Colours 



between Elaps and otlier „Coral-Snakes". 



Black is indicated by crossed lines; in Fig. 6—9 also by vertical lines to empbasize 



the change of originally red into black fields. Eed is left wbite. Yellow is 



indicated by stippling. 

 Tbe black at the left end of each diagram represents tbe first black ring on the 



neck immediately behind the bright yellow bar across the black head ; a pattern 



almost universal in these snakes. 

 Patterns 1—4 belong to the Erythristic series with siugle black rings: E. S. cf. page 8. 

 Patterns 5 — 9 belong to the Melanistic series with donble black rings : M. D. cf. page 5. 

 Patteru 3 indicates that the black rings may vary much in width. 

 Patteru 4 is the commonest pattern of Elaj}s fidvius in Mexico, and the sole dress 



of this siiecies in Northern Mexico and in the United States. — This pattern 



does not occnr in Coronellal 

 Pattern 5. This very common pattern does not occur in any Elapsl In some 



specimens of Coronella micropholis the narrow rings between the black rings 



are red instead of yellow. 

 Pattern 6-9. Conversion of originally red bands into black. If the white or 



yellow interstitial rings are changed "into red, the lütimate result is the iudividual 



tail-pattern of Coronella as figured on Plate 1. 



