-±06 



FAMILY XI, STAPH YLINTB/R. 



gg. Elytral suture longer than thorax. 

 h. Species 3 mm. or more in length. 



i. Longitudinal elevation between the eyes indistinct or nearly 



obsolete ; length 3 mm. 

 ./'. Thorax with median impression very feeble, extending 

 nearly the entire length. vicinus. 

 ./'./'. Thorax with median impression reduced to a simple ero- 

 sion just behind the middle. ingratus. 



ii. Longitudinal elevation distinct ; head wider than elytra at 



base ; length 3.3 mm. 785. scabiosus. 



hJi. Species less than 3 mm. in length. 



k. Thorax widest distinctly before the middle. 



/. Legs black; length 2.6-3 mm. inornatus. 

 //. Legs fuscous ; length 2.5-2.7 mm. placidus. 

 kk. Thorax widest at or behind the middle ; length 2.4—2.6 mm. 



ERIENSIS. 



da. Minute species, length less than 2 mm. 



m. Transverse carina? of abdomen without cusps ; length 1.7-1.9 mm. 



NANUS. 



mm. Transverse carina? with three cusps; form much more slender ; length 

 1.7 mm. pumilio. 



783 (2321). Stenus strangulatus Casey. Rev. Stem. 1884. 39. 



Elongate, very slender. Black, shining, very sparsely and finely pubes- 

 cent; antenme piceous. palpi paler; legs uniform dull reddish-brown. Head 

 nearly twice as wide as long; surface between the eyes deeply excavate, 

 finely and rather sparsely punctate, with two grooves and a median con- 

 vex ridge. Thorax widest before the middle, slightly longer than wide, 

 coarsely and irregularly punctate, the median impression rather wide and 

 shallow, extending two-thirds the length of disk. Elytra at base two-thirds 

 the width of head ; coarsely and irregularly punctate. Abdomen long, feebly 

 tapering, coarsely and sparsely punctate. Length 3-3.5 mm. 



Lake County; ra,re. May 2. Known heretofore from New- 

 York and Detroit. 



784 (2328). Stenus erythropus Melsh., Proc. Phil. Acad. Nat. Sci.. II. 



1844. 40. 



Rather robust. Black, shining, sparsely clothed with short, fine gray- 

 ish pubescence; antenme piceous, palpi and legs piceous-brown. Head be- 

 tween the eyes distinctly excavate, coarsely, closely and evenly punctate, 

 the median ridge low and subobsolete. Antenme longer than width of head, 

 the third joint one-third longer than fourth. Thorax very robust, widest at 

 middle, coarsely, closely and unevenly punctate and with a rather narrow 

 shallow impression extending from middle two- thirds to base. Elytra 

 slightly longer than thorax, coarsely, deeply and unevenly punctate. Ab- 

 domen at base narrower than elytra, thence feebly tapering to apex, coarse- 

 ly and rather closely punctate at base, more finely toward apex. Length 

 4-5 mm. 



