314 PROCEEDINGS OF THE NATIONAL MUSEUM vol.88 



Dorsum of thorax deeply and thickly punctured, areas between 

 punctures minutely reticulated; pubescence mostly short, but longer 

 at posterior margins of pronotum and mesopraescutum ; anterolat- 

 eral angles of pronotum with a wide lamina, anterior dorsal carina 

 interrupted on mesal one-fifth ; parapsidal furrows nearly obliterated ; 

 prepectus narrow, its apex slightly overlapping anterior apex of 

 tegula; mesoscutellum provided with a narrow apical lamina; met- 

 episternum densely and deeply punctured, sparsely covered by long, 

 slender setae; metacoxa stout, outer dorsal area glabrous or very 

 nearly so, ventral and lateral areas provided with setae and large 

 punctures; outer surface of metafemora densely covered by short 

 pubescence, ventral margin with 19 to 24 small, acute, closely set 

 teeth, basal one slightly larger and acute; inner tooth varying from 

 acute to blunt; metatibia with apex acute. 



Propodeum covered by strong, rather irregular carinas, a minute 

 tooth present at each posterolateral angle, spiracular openings nearly 

 vertical; petiole short, glabrous on dorsal side, minutely reticulated 

 on lateral side near base, basal lamina narrow; gaster somewhat 

 compressed, usually slightly smaller than metafemur, third abdom- 

 inal segment usually occupying half or more total length of gaster, 

 abdominal segments 4 to 7 with sparse lateral setae at posterior mar- 

 gins ; eighth tergite minutely pitted and reticulated, sparsely covered 

 by long setae, spiracular openings round; cerci small, almost round, 

 located midway between anterior and posterior margins of epipygium ; 

 ovipositor sheaths provided with sparse, short ventral setae. 



Male: 4.5-5 mm. Antennal scape (fig. 9, e) short and stout; com- 

 bined widths of compound eyes one-half interocular space at level of 

 antennal bases ; inner tooth of metafemur sharp ; petiole slightly more 

 than twice as long as wide. 



Type locality. — Delaware. 



Types. — Holotype, male, 1786, Academy of Natural Sciences of 

 Philadelpliia. The female was described as Smicra encausta Cresson, 

 from Colorado; type, 1789, Academy of Natural Sciences of Phila- 

 delphia. 



The species S. encaiista Cresson was originally stated to be de- 

 scribed from a male, but the type is a female; it differs from the 

 type of S. arcana only in having the anterolateral lamina of the 

 pronotum slightly narrower, but is otherwise identical in structure 

 (except in primary and secondary sexual characters), although some- 

 what darker in color. Neither of these differences is of specific value. 



Host. — ^Unknown. 



Distribution. — Alabama, Colorado, Delaware, Illinois, Manitoba, 

 Minnesota, Montana, North Dakota. 



