292 [December, 



clature of the parts and introduces various new terms, as well as many which 

 have been proposed by the author and other workers earlier. The law of 

 priority is faithfully observed, so that a few names used in the " Noctuidse " 

 volume have had to sink. The nomenclature is becoming rather formidable, 

 but must needs be mastered by all who aim at precision. Mr. Pierce is probably 

 justified in protesting that " such obscure phrases as medio dorsal process" are 

 reprehensible. 



To the earlier volume, it was objected in some quarters that Mr. Pierce had 

 not the courage of his convictions on the question of the genera, or systematic 

 grouping of the species, so that while frequent attention was called to the fact 

 that such-and-such species were " strongly generic," or that others which had 

 been associated with them in the same genus were " very distinct," no new 

 taxonomic arrangement was given, and the author's scheme or views of 

 classification remained difficidt to grasp. In the present volume a com- 

 plete re-classification of the Geometridse, based exclusively on the genitalia, is 

 presented. The ideal method of dealing with the taxonomic question without 

 undue complications as regards nomenclature has evidently still to be devised ; 

 if Mr. Pierce's present method is to be followed in every monograph or memoir 

 dealing with a particular organ or structure, we shall have probably as many 

 systems as there are works of this class, and none will have any claim to accept- 

 ance outside itself. It is a common saying, and almost a platitude, that the 

 perfect system is that which takes account of the whole, organism, but as that 

 can only be reached through a series of specialistic studies such as that upon 

 which Mr. Pierce is engaged, we think he has upon the whole done wisely to 

 present the species in that sequence which his particular studies dictated, and 

 our only hesitation is whether it was equally wise to call his conceptions 

 " genera," or furnish them with generic names. As a matter of fact, however, 

 many of the genera are not diagnosed, so that their characterization is left to 

 conjecture or to laborious deductions from the descriptions of the species. Thus 

 it seems doubtful whether it would not have sufficed to treat the various 

 "groups" (sub-families) as the genera, for these are defined, and then usually 

 follow at once the species, merely with generic names prefixed. 



The author divides the family into two main divisions, Gnathoi and 

 Agnathoi, the former with gnathos developed, the latter with " Gnathos reduced 

 to a mere thickening of chitine, or absent," as seems to have been tentatively 

 proposed by Chapman (see Prout, Gen. Ins. Brephins, p. 6). On the whole it 

 yields satisfactory results — i.e., such as are supported by, or at least compatible 

 with, those deducible from other known characters ; but it is not in itself quite 

 absohite, though " the species falling within the Gnathoi, but having the 

 gnathos rudimentary or atrophied, are so few that they may be left out of con- 

 sideration" (p. xxi). The further characterized groups (sub-families) are, in 

 the Gnathoi, Geometrinie, Ourapterygirwe, Ennominx, Macarinx, Bistoninx, Boar- 

 miinse, Eranninx (Hibemia, auctt. etc.), Gnophinx, Abraxinse, Ptychodinx, 10 in 

 all; in the Agnathoi, Acidaliinx, Cosymbiinx (Zonosoma, Led., etc.), Astheninx, 

 Oporiniinx (Operophtera, etc.), Eupitheciinx, Melanthiinse, Philereminx (ve- 

 tulata and rhamnata only), Lobophorinx, Entepliriinx, Cidariinse, Therinx, 



