ELATERIDAE. 1G3 



preceding by so many important characters, that it might almost 

 be considered as a separate sub-family. The antennae are feebly 

 serrate, and very approximate, situated in cavities limited poste- 

 riorly by oblique ridges ; the front is deflexed before the antennae, 

 and then flattened out ; the mandibles are slender and prominent ; 

 the palpi with the last joint securiform. The lobe of the pro- 

 sternum is very short, and protects the mouth partly; it is sepa- 

 rated by a transverse groove, almost as in Anelastes. The plate 

 of the hind coxae is suddenly dilated internally ; the trochanters 

 are broad, and of the usual size ; the joints 1 — 4 of the tarsi 

 gradually diminish in length and breadth; the claws are finely 

 pectinate to the apex. 



Sub-Family III.— ELATERIDAE. 



The antennae in this sub-family are widely separated, inserted 

 in small foveae under the margin of the front, before the eyes. 

 The mouth is usually anterior ; the mandibles are small and re- 

 tracted, except in the last tribe, in which, too, are found the only 

 genera having the labrum connate with the front. The middle 

 coxae are always angulated externally, with a small, but distinct, 

 trochantin, so that the episterna are not cut off from the coxal 

 cavity. In a few genera of the last tribe the anterior and middle 

 coxae are conical. The tibiae are slender in all the genera. 



The tribes appear to me to be naturally arranged as follows : — 



Antennae received in deep prosternal grooves. Agkypnini. 



Antennas not received in prosternal grooves ; 

 Meso- and nietasternurn connate. Chalcolepidiini. 



Mesosternal suture distinct (side pieces of metatkorax narrow in our 

 tribes) ; 

 First joint of antenna very long. Hemirhipini. 



First joint of antennae moderate ; 



Apex of mandibles obtuse or emarginate. ELATERrai. 



Mandibles with the tip slender, prolonged, acute. Plastocerini. 



Tribe I— AGRYPNINI. 



These insects are easily recognized by the antennae received in 

 grooves excavated along the prosternal sutures; the mandibles 

 are emarginate at tip, or toothed ; the front flat or concave ; the 

 mesosternum not, or but slightly, protuberant; the coxal plates 



