PROC. ENT. SOC. WASH., VOL. 21, NO. 8, NOV., 1919 179 



and middle coxae darker, hind coxae reddish at apices only, all the tarsi 

 and the hind tibiae infuscate. Head, with the eyes, only slightly narrower 

 than the prothorax, front a little impressed each side and with a fine, rather 

 obscure median longitudinal carina, closely and relatively coarsely punc- 

 tured, vertex sculptured similarly to the pronotum. Prothorax cordate, 

 four-fifths as long as wide, sides moderately strongly arcuate from the basal 

 constriction to the apex which is distinctly broader than the base. Anterior 

 margin nearly straight, front angles obtuse but not rounded, marginal bead 

 fine, distinct, basal sinuation of the sides sudden, behind which they are 

 practically straight and parallel, hind angles almost exactly right. Disk 

 finely and sparsely punctured, rather strongly alutaceous and appearing 

 transversely sifbrugose in certain lights. Median impressed line strong, 

 extending in front of the moderately well-marked arcuate anterior line, 

 but not reaching the base nor the apex. Basal impressions vague, broad, 

 nearly circular. Elytra conjointly two-thirds as wide as long, oblong, broadest 

 well behind the middle, humeri broadly rounded and not prominent, apices 

 rather strongly sinuate. Along the side margin are three well-marked broad 

 impressions, one antemedian, one postmedian and the third about one-fifth 

 from the apex. On the disk, the pubescence is so arranged as to give the 

 effect of longitudinal lines in one light or transverse bands in another. Each 

 elytron has a row of shallow foveiform impressions (three on one elytron, 

 five on the other) following the course of the third interval, external to which 

 is a shorter row of three smaller indentations. Marginal stria represented 

 by a row of rather deep elongate punctures, discal striae not impressed and 

 traceable, if at all, by the arrangement of the pubescence and of the minute 

 superficial sculpture. Beneath piceous with a distinct greenish cast which 

 is less strong on the abdomen, smooth except a few fine wrinkles near the 

 bases of the ventral segments. 



Length 5.50 mm. 



Type and one paratype (United States National Museum No. 

 22562), taken by J. M. Jessup on the Porcupine River, Alaska, 

 15 miles below New Rampart House, June 5, 1911. One para- 

 type in the collection of the United States Biological Survey, 

 taken by A. H. Twitchell, Iditarod, Alaska, July 27. 



The presence of a bristle within the hind angles of the pro- 

 thorax places this species in the same category as the European 

 A. cyanicornis, A. festivus and A. flavipes, from all of which it 

 is immediately separated by the small head, this, with the eyes, 

 measuring less than the thoracic width. From A. flavipes it 

 differs also in having the penultimate joint of the maxillary 

 palpi metallic. The Japanese A. semilucidum Mots, is smaller, 

 more parallel, with broader head, more pronounced punctuation, 

 somewhat differently shaped prothorax and dark antennae. By 

 description, the present species differs from A. elongatum in being 



