iiii; w Aii;i; sc . \ \i:.\(;i;i; m-iiri'M-is. _;)( 



\'II. lIvDKMCii \Kis l.ntr. ISI^."). ((Jr. "wntci- dcli-hl.") 



Tlic piMstcriuiiii. iiislc.-i I lA' hciim' uroovi'd fur llic iTccpl ion nl' 

 the fi-oiit ciiil of the .stei'tuil ci-cs;, is entire :iii(l rjiised iiili. ;i sh.-irji 

 carina, ih\^ species oecinvs in the State. 



I'.iT (ITiitT). II Ym;(K iiAHis or.Tisviis S,i\. .jdinii. I'liil. \r:u\. Nat. 8ei.. 

 1 1 i. ls-_':;. LiiM); ilii.I. 1 1. ]-2\K 

 .Miile t'liui.uate-oval : ft'iiiMlc (-hloug-oval. very olidisi' heliiiid. Black. 

 shiiiiiiu: uiulei- surface dark reddisli-hrowii. puliescciil. I'llyli-a each witii 

 I'dur rews o\' distinct punctures, tlie outer imw deulilc. Spine of nicla- 

 stei-inuii net extending- iieyend liind ce\;e. J-en^lli l.". le, mm. 



Coiniuoii tlinuiulidut the iioiiheni half of State; h'ss so in s mth- 

 eni portion. Ai)fil (i-Septeniher ITi. Often taken he;:ea11i i)<i's 

 and stones eh>se to tlie edge of walei"; also at electric liit'ht. 



Tribe III. II VDKOP.Il.Xl. 



Aquatic i^eetles of small size antl of an (»val or heniisi)herieal 

 form, having the thorax at hase always as wide as the base of elytra, 

 and the iiietasternal spine never prolonged hack of the hind eoxtr. 

 The tribe is represented in Indiana by nine genera, separated by 

 Dr. Horn as follows: 



KEY TO INDIANA GENERA OF IIYDKOIUINI. 



«. Last ventral sej;nieut euiarginate : antenna' seveii-Jeinted : elytra with 

 ten stria-; length 2.5-6 mm. \ HI. Berosus. 



(la. Ivast ventral segment entire. 



ft. First and second ventral segments concealed )jy i>lates ; lengtli less 

 than 2.5 nun. IX. Ch.ctartiiria. 



66. Ventral segments not covered. 



c. Antenn;e eight-jointed: c(.lor mostly i)ale; form rounded, convex: 

 length 2.5-:'> mm. X. LACCoiurs. 



(■<: Antenna' nine-jointed: color usually dark. 



(/. Last joint of maxillary italj)! shorter than lliird: length :>.5- 

 7 mm. 

 e. Tai'Si ttve-jointed on all the feet. 



f. Meso sternum with a longitudinal laniin;\ or ]ilate: second 

 joint of maxillary palpi curved, with tlie convexity to the 

 front; elytral imnctures confused. XI. I'hilhydkus. 



ff. Mesosternuin with (.nly a slight median tulierosity: con- 

 vexity of the curved secnnd joint of maxillary paljii lurne<l 

 to the back ; elytral punctures in rows. 



XII. IIki.ocuakes. 

 ee. Tarsi four-jointed on the middle and hind feet. 



ff. Mesosternuni with a feeble ti-ansverse carina: tarsal claws 

 simple; elytra not striate. XII I. Cymbiouyta 



