Mat 17, 1907] 



SCIENCE 



791 



world. The genus Leucozona includes a 

 single species, possibly two. In accordance 

 with this iniquitous, ex post facto law of the 

 ' First Eeviser ' it is now proposed to apply 

 the name Syrphus to this single species and 

 to give to the hundreds now called by that 

 name, the name of a synonym made years ago 

 by the greatest blunderer that ever wrote on 

 entomology. Schiner was remarkably con- 

 scientious, following the usages and rules of 

 his time closely. He, of course, could not 

 imagine that the future historical naturalist 

 would impose so absurd a rule as would make 

 the carelessly designated and wholly unwar- 

 ranted ' type ' of Curtis compulsory ; did not 

 dream that it was necessary for him to look 

 through the writings of every author of high 

 and low degree to see whether Fabricius's 

 types had been arbitrarily fixed. His work 

 was done in good faith. 



This is but one example of the workings 

 of this newly proposed, ex post facto law. 

 There are scores of others not unlike it; 

 in fact, dipterology will be a small chaos until 

 all the present works on the science have been 

 rewritten, and a paradise of the name tinkerer, 

 if such a rule obtains. 



I should not object to the * first 'species ' 

 rule, if it were not made retroactive in such 

 cases as would upset other names established 

 by elimination. Surely those of the past who 

 have done able and conscientious work under 

 accepted usages should not be stigmatized at 

 the caprice of any self -constituted authority. 

 And what assurance have we that a few years 

 hence some other ex post facto law will not be 

 invoked to do the work all over again? New 

 writers will have little opportunity to propose 

 new generic names unless some such historical 

 mine is opened up. 



I really believe that the final solution of the 

 -ever-growing controversies and apparently 

 never-ceasing changes will be some such com- 

 mission as Dr. Davenport has recently sug- 

 gested, an accepted commission to pass upon 

 the validity of names without regard to 

 priority or anything else. And one of the 

 first rules that I should attempt, were I a 

 member of such a commission, would be that 

 lie who digs up a name that has been buried 



for fifty years to replace some other in com- 

 mon use, should be ostracised and debarred 

 from all further use of reputable scientific 

 journals. 



S. W. WlLLISTON 

 TYPES OF GENERA BY FIRST SPECIES 



In a recent article' it is claimed that the 

 first species method is opposed to the law of 

 priority, since it supersedes the action of the 

 first reviser. It is only necessary to reply 

 that the action of the original author always 

 precedes that of any possible reviser, and 

 since the first species method determines the 

 type of the genus solely from the first publi- 

 cation of the original author, it is obviously 

 more in accord with the law of priority than 

 any other method. 



The same writer makes the surprising 

 statement that the method of elimination and 

 that' of the first reviser are parts of one 

 method. As a matter of fact, they are 

 almost diametrically opposed. The elimina- 

 tion method, or the method of residues, tends 

 to leave as the type of the original genus 

 the one left last after all removals. This is 

 usually the most obscure, or unrecognizable 

 species, since the more prominent ones are 

 generally first selected as the types of new 

 genera, or are otherwise removed. The first 

 reviser method, or that of the nomination 

 of types, tends to select some prominent 

 species as the type of the old genus, since such 

 will naturally be first selected by some later 

 author as an illustration. These two op- 

 posed rules are, unfortunately, capable of 

 being mixed in various ways (one of which is 

 illustrated in the article here referred to), 

 allowing of almost an infinitude of methods 

 of selecting types. It is this extreme and 

 most undesirable latitude in the rules that 

 renders those most lately promulgated so un- 

 satisfactory and impracticable. 



Harrison G. Dyar 



U. S. National Museum, 

 April 19, 1907 



A SHEEP-GOAT HYBRID 



What seems to be a hybrid between a sheep 

 and a goat was produced this spring on the 

 ' Science, n. s., XXV., 625, 1907. 



