H. C. FALL 
305 
Male genitalia. — Piceuus brown; broad and strongly concave superiorly, 
both lateral and median lobes strongly curved upward, the former gradually 
narrowed to the truncate tips, the latter subacute at the slightly refk'xed 
apex. 
Length, 7 to 7.8 mm.; width, 4 to 4.3 mm. 
Type locality. — “Canada, taken by Dr. Bigsity.” 
Of this extremely rare species, R.egim])arl, in the Third Sup- 
plement to his jNIonograph gives us a detailed desei'iption, 
drawn from a single female specimen which was sent him by 
Mr. Arrow of the British Aluseum, as being apparently tlu' 
same as Kirby’s type, descril)ed in 1837. This specimen is 
said to be from Lake Huron. So far as I know, no other ex- 
amples had been taken down to the summer of 1917, when in 
looking over a mixed lot of Gyrini taken by Mr. J. B. Wallis 
along the Hudson Bay Railway, six specimens of very large 
size attracted my attention, and suggested the possilnlit}" that 
I had before me representatives of this almost mythical species. 
That these are the true itnpressicullis I have now no doubt 
whatever. They were taken at Picpiitenay River, .July b, 
1917. 
Aside from the size, which is conspicuously greater than of 
any other species known to us, I note that the basal joint of tlu' 
aiitei'ior male tai'sus is here as broad as any that follow, while 
in all our other species it is distinctly less wide than the two 
following joints. Furthermore the first ventral segment is 
shorter and the fifth is longer than in any other s})ecies; while 
the genital organs are absolutely unlike anything else in the 
genus. 
List of North American Species of Gyrinus, ivitk Onyinal 
Bibliogra phic Cita Hons 
Owing to the numerous erroneous references, a coinj^lete 
bibliography is not attempted. The only works that tlu' stu- 
dent need consult are the papers of Aube and L('Cont(', and tlu' 
monograph of Regimbart witli its sev(‘ral sui^phmu'nls. 
1. a. )ninntn.-i Fal)iicius, 1801, Syst. Eloit., i, p. 270. 
2. (1 . rackinghannn.'f.ist L(>C’(jutc, LSOS, Proc. .\cad. Nat. ^ci. Phila., ISOS, pp. 
370, 373. 
3. (I. ventralis Kirby, 1837, Fauii. Bor. .Vmci'., i\ , p. 80. 
4. (1. f rater nn-H C-ouper, 180.5, Can. Kat., 2ud sciK's, ii, p. 00. 
5. (1. aeneolns LeC'onte, 1808, loc. cif., )). .308, 370. 
0. (1. n'oodruffi new species. 
TR.\NS. -CM. ENT. SOC., Xl.Vir. 
