H. C. FALL 
293 
This si)ooies, l)y its metallic black uiulci-body, with thoracic 
Hanks and ei)i})leiira rufous, agrees with a (finis, and as in njflnis 
individuals occur in which the epipleura are so daik as to Ix' 
(piite deceptive. The average siz(' is at least as gix'at as in 
(ijfinis, but the form is less broad, and the punctidat(‘ raflu'r 
than striolate upper surface will at once distinguish it. 
20. Gyrinus affinis A ill >6 
Form broadly oval and oidy moderately eonvex, shiiiiii}*: black with faint 
bluish refleetions, sidi's rather narrowly bronzed; surface without evident 
alutaeeous sculpt uri', but eoviu’ed throufihout with a system of short, viuy 
fine, more or less obliciue scratches, not differing in the sexes. Outer strial 
punctures only slightly coarser, eleventh stria (piite lU'ar the margin. Body 
beneath metallic black, pronotal h>^)omera, epijileura and anal ventral seg- 
ment more or less distinctly rufous. 
Mdle genitalid . — Dull rtifo-testaceous, the median lobe brownish at apex. 
Mt'dian lobe very slender (linear) in about apical third, thence gradually 
widened to base. 
Length, o.G to 7 mm.; width, 3.15 to 4 mm. 
Type locality. — “United States.” 
A very common and widely dispersed north(‘rn sjy'cii's, 
known to me from Maine (Ptiris; Monmouth): N(av Hamp- 
shire (hdirmiiigton) ; Massachustdts ( Wtdxefitdd ; Ntitick; Mon- 
terey)- ('onnecticut (Litchfield): New York ( Keeiu' \ddk'y; 
Afoimt Marcy) : (Quebec (Hull); Alichigan (Pontiac; Alger 
('ountjd: Allierta (Edmonton): British Columbia (Mclbiihd: 
^^’ashington (Olympia): Oregon: C'alifornia (Dunsmuir; LtUxe 
Tahoe; Huntington Lake, Fresno County, TOtJO ft. — Blaisdell). 
It is not entirely certain that this is the true ajfinis of Aubib 
but it is the species so identified by LeC'onte, and we have no 
other which so well fits Aube’s descriittion. Of a certainty, 
no North American Gyrinus is more likely to havt* found its 
way into European collections than this large, widely dis- 
persed and generally abundant speedes. Undoubtedly this is 
the canadensis of llegimbart, who comitares it with ajfinis, 
with which he says k is generally confused. Aulx^ says oi 
ajfinis — “male very finely retietdate, female smooth.” llt'gim- 
Itart says of (tffinis that both male and fenude tirc' finely but 
strongly punctulate,, and that the female in addition poss('ss('s 
an extremely fine reticidation in the form ot oblicpii' ('longati'd 
tireolae. Of his canadensis Pegimbart stiys, llml in bolh s(‘X(‘s 
TRAN.S. AM. ENT. SOC., XLVII. 
