42 GEO. H. HORN, M. D. 



PliATYNUS Bon. 

 P. niyriiiecodes n. sp. — Slender, elongate, pale rufo-testaceous, feebly 

 shining. Head smooth ; antennae slender, longer than half the body, third joint 

 a little longer than the fourth ; thorax oval, narrowed behind, much longer than 

 wide, hind angles rectangular, but not prominent, lateral margin very narrowly 

 reflexed, median impressed line alone distinct; elytra elongate oval, nearly 

 twice as long as wide, humeri very obliquely rounded, disc very feebly convex, 

 lateral margin narrowly reflexed, sinuate near the apex, apices slightly separated, 

 acute, but not prolonged, surface faintly striate and finely alutaceous, strire ob- 

 soletely punctate; body beneath smooth and shining; legs long and slender; 

 front tarsi grooved on upper side, middle and hind tarsi grooved on the outer 

 side from the first to fourth joint. Length .37 inch. : 9.5 mm. 



A slender species of ant-like form allied to dissedus, but differing 

 from that species in its thorax being longer than wide, and by the 

 more narrowly reflexed margins of both thorax and elytra. It re- 

 sembles jejunus also, but is still more slender, and differs in having 

 the front tarsi grooved on the upper side. 



One specimen, Arizona, precise region unknown. 



P. arizoiieiisis n. sp. — Form o( maciili colli s, black, head and thorax feebly 

 shining, elytra opaque, sometimes with a slight violet tinge. Antennae entirely 

 piceous ; head smooth ; thorax broader than long, not narrowed at base, sides 

 regularly arcuate, hind angles broadly rounded, disc subopaque, feebly convex, 

 at sides very slightly depressed, the margin scarcely reflexed, basal impressions 

 shallow and small, median Hue alone distinctly impressed ; elytra oval, the mar- 

 gin very feebly sinuate near the apex, humeri rounded, body winged, disc mod- 

 erately deeply striate, strise obsoletely punctate at bottom, intervals very flat, 

 the third interval with four dorsal punctures along its middle; body beneath 

 smooth, shining; legs piceous-black, tarsi paler. Length .38 inch. ; 9.5 mm. 



This form belongs with our series of black Platynus without me- 

 tallic lustre already sufficiently numerous and difficult to separate. 

 This one differs from ail the others in its opaque surface. The sides 

 of the thorax are scarcely at all depressed, and the basal depressions 

 feeble. It must, however, form a group intermediate between the 

 melanarius and affinis series and that typified by macidicollis by the 

 presence of four dorsal punctures placed in the middle of the third 

 interval. Rarely the last puncture is placed on the second stria. 

 In maculicollls there are usually six dorsal punctures, the anterior 

 three on the third stria and the posterior three on the second. 



Specimens of this species rarely occur with but three dorsal punc- 

 tures. 



Occurs at Camp Grant, Arizona. 



P. laiigtiiflus n. sp. — Piceous, antennse and legs rufo-testaceous. Head 

 piceous, darker than the thorax, smooth ; thorax paler at the sides, one-third 



