106 



THE PRACTICAL ENTOMOLOGIST. 



take characters -which separate one of them from 

 the other, call them generic characters, coin some 

 long-wiuded new generic name, and then — hci/ 

 presto! — we have a new genus. 



Mrs. Jlonks might liave added that, in addition 

 to the discrepancy in nomenclature between Harris 

 and Trouvelot, Dr. Fitch has adopted a third set of 

 names, following English, instead of German or 

 American authorities. It will be found that he 

 names the four moths enumei'ated above, Actias 

 Luna, Atlacus Cecropia, Attacus Proniethea , and 

 Hi/alopliora Poh/plicmus. The genus Hijalophora 

 (in English "glass-bearer"), it may be incidental- 

 ly remarked, was constructed, or as Mr. Grote 

 would say, ''eliminated," by an English writer 

 (Duncan) to receive certain species with "glassy" 

 spots in their wings ; and he had the incredible 

 carelessness to refer the Gecropia moth to this new 

 genus of his, erroneously supposing that it had such 

 glassy spots. If, on the other hand, we reject 

 Packard's and Grote's new genera, and rely exclu- 

 sively on Hiibner, we shall get a fourth set of 

 names, Tropnca Luna, SM7iia C'ccropia, Samia 

 Promcthca and Telea Polijpheinus. And so on, al- 

 uiost ad itifinitxim. 



It will be observed, however, that throughout all 

 these changes in the names of the genera, the spe- 

 cific names remain unchanged. The reason of this 

 is, partly because it is contrary to scientific eti- 

 quette to change any specific name, after it has 

 ones been published and ratified by a good and suf- 

 ficient description, and partly because species have 

 a real existence in nature, while genera, as I be- 

 lieve, are the mere creatures of the human brain, 

 and to a great extent are dependent upon the whim 

 and caprice of the genus-grinder. For example, 

 the very same author will often, at dificrent times 

 and in ditferent publications, refer the very same 

 insect to three or four different genera. Even the 

 very best entomologists have occasionally done this; 

 and with the smaller fry it is almost the rule, rath- 

 er than the exception. Now if, as Agassiz main- 

 tains, genera have as real an existence in nature as 

 species, how does it come about, for instance, that, 

 while all authors have always been agreed that the 

 Promethea moth is a distinct species from the Ce- 

 cropia moth, and all of them give these two moths 

 the same specific names, there is such a wide differ- 

 ence of opinion as to whether or not they belong to 

 one and the same genus — Drury, Hiibner, Duncan, 

 Westwood, Walker, Fitch and Harris holding that 

 they do, and rrof.,Agassiz, Dr. Packard and Mr. 

 Grote holding that they do not '! This argument 

 might be multiplied indefinitely; but one such case 

 is enough for my purpose. 



If my opinion is asked as to the four Insects re- 

 ferred to above, I believe that they belong to three 

 distinct groups, Luna to one, C'ccropia and Pro- 

 mcthca to another, and I'oh/phcmns to a third. But 

 nobody has yet been able to define the difference 

 between a genus and a subgenus, and whether these 

 groups are genera, or subgenera, or mere generic 

 sections, and whether, if they are subgenera, sub- 

 genera ought to receive a distinctive name, and 



whether in that event we ought to write Atlacus 

 (s((m/«) cccropia or Samia cecropia, are doubtful 

 and disputed questions, about which I do not much 

 trouble my head. Upon such questions authors 

 always have difi'ered, and always will difler to the 

 end of time. And, after all, they are questions of 

 words, rather than questions of things ; and science 

 ought to deal as much as possible in things, and as 

 little as possible in words. Unfortunately for the 

 cause of peace and quiet, the scientific world is, not 

 a monarchy, but a democracy; and there is no tri- 

 bunal to which we can, in the last resort, appeal, to 

 resolve such knotty and insoluble problems as the 

 above, or to fine and imprison refractory and im- 

 penitent members of the worshipful fraternity of 

 Genus-grinders. 



One cause, perhaps, of the undue tendency in 

 these modern times towards the multiplication of 

 new genera, is a practice which has been introduc- 

 ed, of quoting as authority for the name of a spe- 

 cies, not the name of the author who first described 

 that species, but the name of the author who has for 

 the first time referred it to the latest and most fash- 

 ionable new genus for the current year. Thus the 

 same insect, which iu 17G7 is Attacus Cecropia 

 Linnaeus, becomes in 1816 Samia Cecropia Htib- 

 ner, in 1852 llyaloplwra Cecropia Duncan, and in 

 18G5 Plati/samia Cecropia Grote. According to 

 this rule, Linnajus is robbed of the honor of attach- 

 ing his name to the species which, as all allow, he 

 was the first to name and describe; and a positive 

 premium is held out to writers to do what most mo- 

 dern naturalists, with the honorable exception of 

 Lacordaire and a few others, are already too apt to 

 do, namely, to multiply unnecessarily the number 

 of new genera. 



As long ago as 1807, the great French Entomo- 

 logist, Latreille, expressed himself as follows : — 

 " New genera should not be founded upon trifling 

 differences, but only when the difl'crences are con- 

 siderable, and when necessity demands the subdivi- 

 sion of an old genus, for example, when the num- 

 ber of species included under that genus is incon- 

 veniently large." (^Gcn.Crugtac. Insect III, p. 61.) 

 It is greatly to be desired that some of our 

 younger North American naturalists would pay a 

 little more attention to these eminently useful and 

 practical suggestions. B. D. W. 



CUBEANT PLANT-LICE. 



{Apliis ribis.) 



[From the PnooEEDiNQS or the Alton, III., Horticultu- 

 ral Society, May 2, 1807.] 

 Mr. J. Huggias, chairman of tlie committee on Entomo- 

 logy, presented leaves of "Currant," evidently diseased — 

 cause to him unknown, The leaves were marked by red- 

 dish-brown blotches of irregular form, the surface when- 

 ever attacked was raised up and thickened. 



Remaiiks by B, D. W. — From the description, 

 this is probably nothing but the work of the Cur- 

 rant Plant-louse, (Aphis rihis). I have referred 

 to it more fully in my article on Plant-lice, in the 

 Practic.vl Entomologist, II, pp. 37 — 8. If it 

 is not this, I do not gee what else it can possibly 

 be; unless the Alton Currant-bushes are afflicted 

 in some manner unlioown in Northern Illinois. 



