Platynin^ 29 



wide as the prothorax, the humeri rapidly rounded; tips rounded, 

 the sinus long and shallow but distinct; striae moderate, smooth, 

 grooved, the intervals flat, the punctures three in number; met- 

 episterna very elongate; tarsi slender, the upper surface bisulcate. 

 Length ( 9 ) lo.o mm.; width 3.7 mm. Arizona (Huachuca I\Its.), — 

 Schaeffer longiceps Schf . 



Of the two examples of guerrerensis at hand, the second has the 

 elytra slightly though evidently less elongate than in the type and 

 with the lustre more cupreo-violaceous. The tarsi are densely 

 hairy beneath, the fifth joint long, wholly nude, very slender 

 basally and inflated distally; the claws are long. In longiceps, a 

 specimen of which was sent to me for description by Mr. Schaeffer, 

 the tarsi are feebly and very inconspicuously pubescent beneath. 



Group IV {sinuatus) 

 Subgenus Anchomenus in- sp. 

 In deciding upon some type which may be known permanently 

 as Anchomenus Bon., we encounter much uncertainty, for Dejean, 

 Duval and others all seem to have different conceptions of what was 

 really intended to be more essentially typical by Bonelli. In 

 deciding upon some form which shall be truly representative of 

 Anchomenus, I think we are warranted in taking some one of the 

 species described under that name by Dejean, and sinuatus was 

 there included. It seems possible, however, that in choosing 

 sinuatus to play this part, we are approaching the true European 

 Platynus Bon., as represented by complanatus, rather closely. 

 Anchomenus as here understood has, however, a somewhat more 

 convex form of body, as a rule, than might be inferred of the true 

 Platynus. The outline is always somewhat ventricose, the antennae 

 more or less long and slender, the third joint varying from decidedly 

 shorter to evidently longer than the fourth. The prothorax is 

 subcordiform, with well reflexed sides, sharp though not necessarily 

 right basal angles, except in a very few cases such as stygicus Lee, 

 and distinctly impressed foveae, and the elytra have rapidly rounding 

 humeri, indicating well developed hind wings in all our species. 

 So far as the described species are represented in my collection, the 

 following scheme of arrangement might be proposed : 



Third antennal joint evidently longer than the fourth; body generally 

 deep black, with deep striae and three dorsal punctures. [Section 

 Anchomenus in sp.] 2 



