(318 FAMILY XXV. HJSTEKID.TO. 



is usually wholly absent and the other striae are not as well devel- 

 oped as in Hister. As noted above, our species mostly occur along 

 shores beneath dead fish, though several of them may be found 

 anywhere beneath caiTion. The' genus is a large one. 79 species 

 being listed from the United States, while three others are here- 

 A\ith described. Since the form of and characters pertaining to the 

 prosternum are nnich used in classification, the under part of the 

 body should be clean, and if too small to mount on a pin, the speci- 

 men should be set with the card point attached to the abdomen so 

 as to expose fully the front of the under side. 



For convenience the Indiana species are separated into two 

 groups : 



KEY TO GROUPS OF INDIANA SAPUINUS. 



a. Front of bead not margined. Group A. 



aa. Front of head distinctly margined. Group B. 



Group A. 



To this group belong the Indiana species of Groups II, IV, V 

 and VI of Horn, his Groups I, III and VII not being represented in 

 the State. 



KRY TO SPECIES OF GROUP A. 



(/. I'rostenium flat, its marginal strife horizontal and united in front; su- 

 tural stria very short, basal; length 2.5-3.5 mm. 1182. rotundatus. 

 iKi. I'rosternnm at least moderately convex, distinctly striate. 



I). Striae of prosternum parallel, horizontal, abbreviated in front; inter- 

 nal subhumeral stria represented by a row of rather coarse, dis- 

 connected punctures; length 8.5-4 mm. 1183. postiiumus. 

 hh. Strife of prosternum divergent in front and ascending. 



c. Prosternum without a pit or fovea on each side near the front 

 margin ; head with a distinct stria e.xtending slightly along the 

 front above the eye. 

 d. Fourth dorsal stria feebly arched at base, not joining the su- 

 tural, the latter short; area between the dorsal strife coarsely 

 and densely punctured; length 4-6 mm. 1184. lugens. 



<JfL Fourth dorsal strongly arched at base, usually joining the su- 

 tural; area between the dorsal stria^ very little or not at all 

 punctured ; length 4.5-5.5 mm. 

 <\ Sutural stria wanting at basal and apical i)ortions, visible for 

 a very slight extent at middle only. 1185. imperfectus. 

 re. Sutural stria distinctly impressed at apical portion and join- 

 ing the apical marginal stria ; surface brilliant metallic 

 green or bronze. 1186. pennsylvanicus. 



cc. I'rosternnm with a small but distiuft fovea on each side in which 

 the stria ends ; stria on front above the eye rarely present. 

 f. Pygidiura with a deep marginal groove at apex. 



1187. ASSIMIMS. 



