THE CLICK BKETI.KS. 701 



'Ill-vision of the Klateridte of the United Slates," in 

 Trans. Amer. Philos. Soc., X, 1853, 405-508. 



Horn. "A Monograph of the Species of the Subfamilies Eucne- 

 mina\ Cerophytina? and Perothopinse inhabiting the United 

 States," in- Trans. Amer. Entom. Soc., XIII, 1886, 5-58. 



For convenience the family is first divided into subfamilies, and 

 these, in turn, into tribes and genera. Of the five subfamilies rec- 

 ognized, representatives of three have been taken in Indiana, while 

 those of a fourth perhaps occur. 



KEY TO INDIANA SUBFAMILIES OF ELATEBIOflS. 



a. Iliiul cu.xa 1 dilated into plates which cover in part or entirely the 



thighs; tmehanters of middle and hind legs very small. 

 b. Labrum concealed; antenna 1 somewhat distant from the eyes, their 

 insertion narrowing the front. 



Subfamily I. El <M:MI.\.E, p. 701. 

 bb. Labrnm visible. 



c. Labrum free; antenna' arising near the eyes under the frontal mar- 

 gin. Subfamily II. ELATERIN.^E, p. 713. 

 cc. Labrum transverse, connate with the front; ventral segments five; 

 claws serrate. Subfamily III. PEROTHOPIN.E, p. 772. 

 IHI. Hind c(ix;e not dilated into plates; trochanters of middle and hind legs 

 very long; labrum short, transverse, connate with the clypeus ; tarsal 

 claws serrate. Subfamily IV. CEROPHYTINJE, p. 77.">. 



Subfamily I. EUCNEMINAE. 



Head convex, deflexed, and resting against the sternum in re- 

 pose ; labrum absent or very slightly visible ; antenna 3 inserted upon 

 the front at the inner extremity of transverse grooves ; prosternum 

 movable, but less so than in the Elaterime, without a lobe in front. 

 The majority of the species are rare, and the larvae have a striking 

 resemblance to those of the family Buprestidie, both in form and 

 habits, being abruptly enlarged in front, and usually occurring in 

 wood which has just begun to decay. Representatives of twelve of 

 the 22 genera are known from Indiana, while those of four others 

 perhaps occur. 



KEY TO INDIANA (IKNERA OF Et'CNEM IN.E. 



a. Last joint of maxillary palpi acute; prosternal sutures and side margin 



parallel; bases of antenna' moderately distant. 



b. Tibia 1 broad, compressed: length <i-S mm. I. MELASIS. 



bb. Tibia? slender; length 4-7 mm. II. THAROPS. 



mi. Last joint of maxillary palpi dilated; prosternal sutures and margin 

 converging; bases of antennae close together. 



