Xiv INTRODUCTION. 



forms have a very distinct aspect, and are barely, if at all, separable 

 from Xanthia.; others, again (G. illoba, necopina, micacea, stramentosa, 

 petasitts and nitela) are extremely like C. leucostigma, and allies. It is 

 difficult to know what to do with groups of this kind, based, perhaps 

 correctly, upon the mere clothing of the thorax or some such apparently 

 trivial character ; they appear to be natural genera, and therefore, I 

 leave them as I find them " (< Trans. Ent. Soc. of London,' 1890, p. 

 678). Can anything be more strikingly illogical ? Commencing with 

 a statement " that the members of this genus seem chiefly to differ &c., 

 by their greater tendency to become greasy," and that some of these 

 same species have " a very distinct aspect, and are barely, if at all 

 separable from Xanthia" Mr. Butler concludes by calling them "natural 

 genera," and is satisfied " to leave them as he found them." That is, 

 I suppose, they form a natural group, because they get " more greasy 

 than one genus," and are "indistinguishable from another." Truly 

 a scientific division, and one that perhaps illustrates Mr. Butler's 

 characterisation of other genera. 



Will Mr. Butler explain on what grounds he separates our Plastenis 

 retusa from P. snbtusa, placing the latter under another unearthed 

 generic name of Hiibner's, called Ipimorpha ? We do not learn what 

 Mr. Butler knows about subtusa, but he tells us what he knows about 

 retvsa, a not uncommon species within a few miles of the British 

 Museum. In the ' Trans. Ent. Soc. of London,' 1886, p. 131, the spe- 

 cimens from Japan were named Cosmia curvata, i.e. when Mr. Butler 

 thinks he has a new species, he finds its generic characters good enough 

 for Cosmia. He then writes of them : " These Japanese specimens 

 are slightly larger and darker than most European examples : when I 

 named Cosmia curvata, we had no European representative in the 

 general collection " (< Trans. Ent. Soc. of London,' 1890, p. 681). In 

 other words, Mr. Butler excuses his want of knowledge of a species 

 fairly common just outside the London suburbs, because there was no 

 " European representative in the general collection." This want was 

 supplied, Mr. Butler states " by the acquisition of the Zeller collection," 

 and then, I presume, the generic characters which led Mr. Butler to 

 place the specimens from Japan in the genus Cosmia, vanished, and the 

 species returned to its natural resting place in Plastenis, where we find 

 it in the Trans. Ent. Soc. of London,' 1890, p. 681. But why has 

 subtusa gone over to Ipimorpha ? Perhaps Mr. Butler will tell us 

 whether on such sterling characters as led retusa into Cosmia from 

 1886 to 1890, to be wafted back by a happy afterthought into 

 Plastenis ? 



These are some of the points which struck me on the examination 

 of the papers called ' Notes on the Synonymy of the genera of 

 Noctuites,' published in the Trans, of the Ent. Soc. of London,' 1890, 

 pp. 653-691. 



I will only add with regard to this matter, that serious consider- 

 ation should be given by the powers that be, that in future, any his- 

 torical and valuable collections, like the Grote and Zeller collections, 

 should be left in their entirety to illustrate what such masters at their 

 work themselves intended, and not allow them to be distributed, and 

 in the humble opinion of the writer, ruined by those who fail to 

 understand them. 



4. IDENTICAL AND KEPUESENTATIVE SPECIES IN OTUEK CONTI- 



