PTEROSTICHIN^: 377 



mexicanus Chd. (1'Abeille, 1875, p. 44). At all events, the char- 

 acters given by Chaudoir to distinguish his mexicanus from cyani- 

 color Chd. (cyaneus \\ Lee.) fit snowi very well; that is: it is much 

 larger than cyanicolor, similar in coloration and with a notably more 

 elongate prothorax. Mexicanus is said by Bates to occur at Gua- 

 najuato and Oaxaca; snowi was described from extreme southern 

 Arizona. 



Dysidius Chd. 



This genus is very exceptional among the allies of PterosticJms in 

 having male sexual characters recalling those of Amara, but here 

 the pubescence on the inner side of the posterior male tibiae is of a 

 somewhat different character, being coarser and erect. Besides 

 mutus Say, the genus will include purpuratus Lee., and the follow- 

 ing varietal form : 



Dysidius purpuratus ssp. trinarius nov. Similar in almost every way 

 to purpuratus, but less robust and with the elytral coloration still more 

 shining and metallic, being of a more aeneo-purpurate character; it also 

 differs in having the sides of the elytra more gradually rounding at base; 

 subapical sinus of the elytra a little shorter and more distinct. Length 

 (cf) 11.5-12.8, (9) 11.7-14.0 mm.; width (c?) 3.8-4.6 , (9) 4-3-5-Q mm. 

 Pennsylvania (Camphill), A. B. Champlain. A large series. 



LeConte described his purpuratus from Ohio, and the differences 

 noted distinguish the species as it occurs to the west and east of 

 the Appalachian Mountains. I have had occasion to notice this 

 geographic differentiation in several other cases, such as Cicindela 

 and Tetraopes. The dimensions of my single female representative 

 of purpuratus are 14.5 by 5.5 mm. 



Parargutor n. gen. 



The species are, so far as known, few in number in this generic 

 group, which is peculiar to the true Pacific coast fauna. There 

 are two distinct species in my collection at present, which may be 

 known easily as follows : 



Body subparallel, moderately convex, black, shining, the legs black or 

 piceous-black, the anterior male tarsi ferruginous to piceous; head 

 fully three-fifths as wide as the prothorax, the sulci feebly converg- 

 ing; front convex, with some irregular longitudinal strigilation lat- 

 erally; antennae black, the tip ferruginous, about as long as the head 

 and prothorax, the latter very evidently wider than long, the sides 

 distinctly sinuate basally, the foveal region abundantly punctate, 



