402 FAMILY XI. — STAPHYLINIDiE. 



KEY TO INDIANA GROUPS OF STENUS. 



0. Abdomen sti'ongly and distinctly margined along the sides. 



6. Fourth joint of tarsi simple. Group /. 



66. Fourth joint of tarsi bilobed. Group //. 



aa. Abdomen not distinctly margined, faint traces of a marginal line being 



visible only on first segment. 



c. Fourth joint of tarsi simple or but slightly enlarged. Group ///. 



cc. Fourth joint of tarsi distinctly bilobed. Group IV. 



Gkoup I. 

 This group, on account of its size, Casey also separated into the 

 following divisions : 



KEY TO DIVISIONS OF GROUP I. 



a. Elytra each with an orange spot near the middle of tlic disk. 



Division A. 

 ail. Elytra without i)ale spot. 



6. Punctures in some portion of the elytra more or less joined or foales- 



cent, sometimes only in twos or threes, sometimes in long channels. 



c. The channels or rows of punctures in some one spot on the surface 



of each elytron arranged in a spiral or whorl which is complete 



or very nearly closed. Division B. 



ec. The channels or rows of united punctures often sinuous but never 



forming a completed vortex or whorl. 



(I. Thorax with a more or less distinct median channel or groove. 



Division G. 

 M. Thorax without trace of median groove. Division D. 



66. Punctures of el.vtra all isolated and distinct one from another. 



Division E. 

 Division A. 



The species of this division ai'e among the largest in the genus. 

 They are easily recognized by the orange colored spot on each ely- 

 tron. Two species have been talten in Indiana, while another 

 doubtless occurs. 



KEY TO SPECIES OF DIVISION A. 



a. Femora black; length 4.5-5 mm. 778. btpuni tatus. 



nit. Femora not black, ranging in color from dark piceous-bvown to dull yel- 

 low. 

 6. Head wider than elytra, spot on latter bilobed ; length 3.6-4 mm. 



779. COLON. 



66. Head equal in width to elytra, spot rounded; ninth and tenth joints 

 of antennae equal ; length 3.S 4.4 mm. semicolon. 



778 (2303). Stenus bipunctatus Eriehs., Col. March., 1S37, 530. 



Rather robust. Black, feebly bronzed, shininp;, very finely and sparsely 

 pubescent; elytra each with a small, palo, rounde<t spot just behind tlio 

 middle. Head less than twice as wide as loim. deeply excavated and finely 

 punctured between the eyes ; antennie reaching; middle of thorax, the third 



