KEVIEWS. 279 



prove very useful to those for whom it is intended. One would like to 

 have the family name labels in the Rhopalocera as they are given in 

 the rest of the list. As to being up-to-date, that is quite an impossi- 

 bility for any list in our present period of rapid advance and change, 

 but a good attempt has hero been made to more or less assimilate 

 modern views, but not always with complete success. We get such 

 combination as Lijcaena ari/iis, an/u>i right for the old aeiioii, Lycaena 

 certainly wrong even if the generally used Plebeius be wrong, as some 

 aver. Again, Adopaea thaiimas, Adopaea up-to-date, thaiinios is the old 

 name for what has long been called lijica and now called by the original 

 name fiava. Generic names can never be stable, their comprehension 

 must ever be variable as our knowledge increases and our work becomes 

 more intensive, but they should never be interchangeable. Liicacna and 

 avion must come together ; arinn is the unalterable type of the genus 

 T/i/caena, and cannot be in Noiiiiade.t. It would have been better to 

 duplicate a laame like Diacrisia sanio with its time-honoured synonym 

 Kiithenionia rtisstda, a practice which, in the Noctuid portion of the list, 

 has been advisedly followed to a large extent. Why huperina 

 gueneei, a species so abundant in Lancashire, is omitted, and the 

 doubtfully accidental L. duinerilii inserted, we cannot explain. We 

 note a few slight errors m spelling, Eachloe for Eucldo'e, Xanthorhoe 

 for Xanthorhoe, actaeon for acteon, etc. No label list would suit some 

 of us ; one we made ourselves would be out of date with us in a 

 month or two. 



;^EYIEWS AND NOTICES OF BOOKS. 



The Genitalia of the Geometrid^ of the British Isles, by 

 F. N. Pierce, F.E.S. (110 pp., 48 plates Avith 450 figs.). Price 10s. 

 post free, from the author. — More than five years have elapsed since 

 the vohime on the "Genitalia of the British Xoctuidae" was published, 

 and during that interval, no doubt owing largely to the influence of 

 the knowledge there collected and collated, lepidopterists generally 

 have come to look upon the facts obtained by the investigation of the 

 genital organs as of extreme importance in all classificatory work, and 

 even as often affording the critical test for the determination of species. 

 Not only is this so with Lepidoptera, but the study of these organs in 

 both the Diptera and the Coleoptera has become most interesting to 

 the ordinary student, and often the main indication relied on by 

 systematists in dealing with otherwise diffieulfc families. 



Like the former volume, the present work deals with facts mainly, 

 although wherever the genitalia indicated want of correlation with 

 the characters hitherto depended upon for classification this has been 

 taken into account. The names of genera and species have been 

 revised by Mr. L. B. Prout, and for those he is " almost entirely 

 responsible." On page xxvi., etc., XantJiorluc should be Xanthorhoe'. 



In the former volume only the organs of the male sex were figured 

 and those minus the penis, but in the present volume it has been 

 found necessary to give in each case not only the latter part and its 

 attendant structures, but also to figure the female apparatus with a 

 figure of the bursa copulatrix, which often lies some distance from the 

 other organs in the abdomen in the perfect insect. 



"In order to test the validity of this principle," the author has 



