THE CLICK BEETLES. 701 



L(('ontc. — '-'Revision of the ElateridiE of the United States," in 

 Trans. Amer. Philos. See. X. 1S53. 405-508. 



Horn. — "A ^lonograph of the Species of the Subfamilies Eucne- 

 minse, Cerophytinas and Perothopinte inhabiting the United 

 States, ' ' in Trans. Amer. Entom. Soe., XIII, 1886. 5-58. 



For convenience Ihe 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 INDI.iXA SCEFA.MILIES OF ELATEEID.E. 



a. Iliiicl cox* dilated into plates which cover in part or entirely the 

 thighs; trochanters of middle and hind legs very small. 

 Ij. Labrum cciiicealed; antennae somewhat distant from the eyes, their 

 Insertion narrowing the front. 



Subfamily I. Euc.xejiin'.e, p. 701. 

 66. Labrum visible. 



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

 gin. Subfamily II. Elateein^, p. 713. 

 n: Labrum transverse, connate with the front; ventral segments five; 

 claws serrate. Subfamily III. Pekothopin^, p. 772. 

 (((/. Hind coxas not dilated into plates; trochanters of middle and hind legs 

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

 claws serrate. Subfamily IV. Cerophytis^, p. 77.3. 



Subfamily I. EUCNEMINAE. 



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

 pose ; labrum absent or very slightly visible ; antennae inserted upon 

 the front at the inner extremity of transverse grooves ; prosternum 

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

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

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

 habits, being abruptly enlarged in front, and iisually 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 GENEKA OF ErcXEMIN.E. 



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



parallel ; bases of anteun.-e moderately distant. 



6. Tibiic liroad, compressed; length (j-S mm. I. Melasis. 



66. Tibise slender ; length 4-7 mm. II. Thabops. 



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



converging; bases of antennsE close together. 



