1918] Aldrich—Notes on Diptera 35 
given by Knab as 1897 in Science for January 14, 1916,—presum- 
ably he took it from specimens sent by Johnson to Coquillett for 
determination. The earliest date on specimens in the collections of 
the Illinois State Laboratory of Natural History is August, 1908, 
and Tucker reported it from Kansas in the same year (Kans. Acad. 
Sci., xxii, 278, 1908), but probably collected it earlier. In the 
Pacific Northwest, I collected a specimen at Pendleton, Ore., on 
May 19, 1907; Mr. Wm. M. Mann secured two at Wawawai, 
Wash., on Aug. 30, 1908; and it was common on carrot flowers at 
Moscow, Idaho, on Sept. 4, 1908. It was in Arizona in 1910 (C. 
N. Ainslie, Proc. Ent. Soc. Wash., xiii, 118). These items may be 
of service in tracing the spread of the species. 
(h) I am indebted to W. H. Dall, of the National Museum, for 
‘further information about the Psilopus of Poli, 1795, which was 
long supposed to preoccupy the same name as applied to a genus 
in the Dolichopodide. Poli’s large work, “*Testacea utriusque 
Sicilize,”’ is unique as a taxonomic effort, in that the writer used a 
complete double set of names,—a genus and species for each kind of 
shell, and an entirely different genus and species for the soft parts 
of the same mollusc. Thus the system is tetranomial rather than 
binomial, and Dr. Dall informs me that it is considered by taxono- 
mists in Mollusca to be entirely outside of nomenclature; he added 
in reply to my question that he was not aware of any controversy 
whatever on the point. This is the same point of view expressed 
by Sherborn in Index Animalium, noted by me in Canadian En- 
tomologist, 1910, 100. Since it seems that Poli’s work is the same 
nomenclaturally as if it had never been written, there can be no ob- 
jection to the use of Psilopus by Meigen in 1824. 
In this connection it may be well to add that the distinctions 
upon which I based Gnamptopsilopus 1893, and recognized Agono- 
soma as distinct from Psilopodinus in my Catalogue of 1905, break 
down entirely in the oriental region; so I would not include all in 
Psilopus. 
