THE GENITALIA OF THE BRITISH NOCTUIDjE. 91 



process that may be true scaphium; its main diamond-shaped portion 

 has the anal aperture at its extremity. We have not seen such a piece 

 elsewhere, it obviously deserves further study. What he calls the 

 ■*' vinculum," has been called the " saccus," which has the priority. The 

 penis seems to have been the name given at first to the "ffidoeagus," 

 under the impression that it was the whole organ. The name must 

 belong to the whole intromittent organ, the solid portion being the 

 -" jedoeagus" (called "penis-sheath" by Jordan), and the eversible mem- 

 brane called by Jordan the "penis," by Pierce the "vesica." We think 

 the latter a very unfortunate name, but it appears to ha\e priority. 

 Petersen calls it " Schwellkorper," whether originally or not, I do not 

 know, but this seems no more a definite name than that frequently 

 given it, of eversible membrane. The portion called by Pierce the 

 " juxta," is called by Dr. Jordan the "penis-funnel." We do not 

 recollect on what authority, but we have called this for a long time 

 the "penis-sheath," a name found in German authorities as " penis- 

 tasche," and "penis-scheide," but unfortunately, applied by Dr. Jordan 

 to the " aedceagus." 



The names of the parts of male genitalia in lepidoptera that have 

 priority are : 



9fH Abdominal segjient : 



1. Tergite . . Tegumen. 



2. Sternite 



2rt carries .. Clas2)s {Harpagoiies), " after-klappen " (Lederer), 



divided into Valves and Harpe. 

 2h sometimes prolonged upwards as Saccus, has at its posterior 



inferior border (centrally to appearance) 



3. Penis-sheath, through which passes the Penis, consisting of — 



'3(1 J'ldoeagus — a hard tube (the Penis of many, the Penis-sheath of 



Jordan). 

 36 Kvernihle membrane — ? erectile, the Vesica of Pierce, the Penis 



of Jordan. 

 10th Abdominal segment : 



1. Tergite . . Uncus. 



2. Sternite . . ScapJtium. 

 Centrally the Anus. 



We may very possibly have overlooked some authorities, but, so far 

 as we know, the above is correct. 



Some of our readers, in noticing this first really comprehensive 

 etibrt to deal with the subject as it affects the British fauna, may 

 expect us to say a few words on the value of a study of these structures, 

 from several practical points of view. The commonest question is — 

 Can we depend on them to provide satisfactory specific characters '? 

 Though the answer to this question is broadly yes, we should like to 

 say that it has its limitations, and that confident assertions of their 

 value in all cases, which do not always hold good, have led many lepi- 

 dopterists to the conclusion that they are I'eally of very little use. The 

 common sense of the matter seems to be, that these parts aflbrd, just 

 like any other structures of an insect, characters that may or may not 

 be decisive. The chances are great that, when other characters leave 

 much uncertainty, the appendages will clear up all doubt, but there 

 are exceptions. There are other cases where the appendages, perhaps 

 from insufficiently close or extensive observation, would leave doubt, 

 when otherwise there is none. We may here refer to one common 

 misapprehension. Everyone is ready to say or agree that any classifi- 

 cation grounded on one character only is necessarily erroneous. But 



