246 THE CANADIAN ENTOMOLOGIST. 



THE GENUS PSTLOPUS OF AUTHORS. 



BY J. M. ALDRICH, MOSCOW, IDAHO. 



In the Journal of" ihe New York Entomological Society, X., 140, 

 1902, footnote, Mr. Coquillett called attention to a serious error of mine 

 in my revision of what I called the Psilopinje (Diptera, family 

 Dolichopodidise), by which I applied the new name Gnamptopsilopus to 

 that portion of the old genus Psilopus containing the type species 

 plaiypterus. But little investigation was needed to assure me that the 

 criticism was just. This gave occasion for an overhauling of the literature 

 of the group, and I undertook to ascertain what name ought to be used 

 for Psilopus, which has been known for many years to be preoccupied. 

 Some of the papers needed were hard to obtain, which delayed my task ; 

 but the main difficulty was the host of subsidiary questions, historical and 

 critical, which rose up to confront me. I have never found anything like 

 it in previous excursions into the realm of nomenclature. I doubt very 

 much if any two zoologists could independently investigate the subject 

 and come to the same conclusion ; at least, there are a number of different 

 names for which plausible arguments can be made. It would require a 

 lengthy article to set forth all the queer questions connected with the case; 

 I dare not attempt it, partly because it would not be worth the room, and 

 partly because it would make subsequent change too easy. Instead of 

 offering a choice of several names, I give my conclusions and a few notes, 

 and particularly request that any future worker in the family who may 

 wish to use other names for the genera will do as I have done — examine 

 all the literature and then ponder the matter one year before making any 

 change. 



The two genera which I have formerly called Gnamptopsilopus and 

 Psilopus should stand as follows : 



Agonosoma. 

 Guerin-Meneville, Voyage . . . . sur la Corvette ; Zoologie, Tome 



II., partie 2me, p. 293. Paris, 1838 (title page gives date 1830). 



On the plates the genus is called Chrysosoma. 

 Fallen, Dolichopodes, 23, 1823 (Leptopus, preoc). 



Meigen, Syst. Beschr. Europ. Zw. Ins., IV., 35, 1824 (Psilopus, preoc). 

 Zeller, Isis, 1842, 831 (changes Psilopus to Sciapus). 

 PBigot, Annales Soc. Ent., France, 1859, 215 (Margaritostylus, in part). 

 Rondani, Dipt. Italicse Prodromus, IV., 11, 1861 (changes Psilopus to 



Psilopodius). 



