No. 500] 



NOTES AND LITERATURE 



559 



the characters must be determined; (2) geographic probabilities must 

 be utilized; (3) similarities and intergradations must be sought." 



As a result the 43 forms (20 species and 23 subspecies) recog- 

 nized by Cope in his posthumous work "The Crocodilians, 

 Lizards, and Snakes of North America" (Rep. Smiths. Inst., 

 1898), are reduced to nineteen; and of the twenty-two names 

 given by Cope eighteen appear only as synonyms. Nearly 

 seventy names have boon conferred on these nineteen forms, or 

 an average of three and a half for each. 



Dr. A. E. Brown, the last preceding reviser of the group, in 

 his "Review of the Genera and Species of American Snakes, 

 north of Mexico." published in 1001. " reduced the number of 

 forms to eighteen — ten species and eight subspecies: he pro- 

 ceeding on somewhat the same lines as Ruthven, namely, "that 

 a knowledge of the laws under which forms are developed is to 

 be best gained by a study of variations." "While the number 

 of forms admitted by the two authors is practically the same, 

 the taxonomic results are widely diverse. 



Dr. Ruthven believes that the garter-snakes will be found to 

 furnish excellent material for experimental research, as they are 

 hardly in captivity, and prolific ; and that the first problems to 

 be attacked are the inheritability of scale characters and the in- 

 fluence of inbreeding and unfavorable conditions of food and 

 temperature. But it is to be remembered that experimental re- 

 search must necessarily be conducted under unnatural conditions, 

 and that the results do not necessarily show what has taken place 

 under natural environments. "While the results thus obtained 

 are always interesting and suggestive, they can not be looked 

 upon as conclusive 1 respecting what has actually occurred under 

 natural conditions. 



J. A. A. 



LEPIDOPTERA 



Hybrid Lepidoptera. — Although published more than a year ago, 

 Mr. J. W. Tutt's account of hybridization and mongrelization in 

 Lepidoptera is probably scarcely known to evolutionists in this 

 country. The two chapters in which he sums up and discusses all 

 that is known on these subjects are prefaced to a much larger 

 work, the first volume of the "Natural History of the British 



•Proc. Acad. Nat. Sci. Phila., 1901, pp. 10-110. 



