ELATERIDAE. 189 



and not margined ; the mandibles are tootlied near the tip; (he 

 prosteriuini is furnished with a long lobe in front; the sutures 

 are double, nearly straight, slightly exeavated in front; the coxal 

 plates are gradually dilated inwards and toothed at the origin of 

 the thighs ; the tarsi are not lobed, but very densely i)ubescent 

 beneath, with the joints 1-4 gradually deereasing in length ; the 

 claws are simple. 



Tribe v.— PLASTOCERINI. 



In this tribe are comprised certain genera which recede from 

 the true Elaters to approach the Cebrionin^ ; thus, the sixth 

 ventral segment is usually slightly visible, and in the female of 

 Eu'tliysanius becomes equal to the other segments. The same 

 sex is further remarkable for the elytra being very short, and 

 the wings wanting; in the female of Aplastus the elytra are also 

 abbreviated, but the wings are present. 



The following characters distinguish this tribe: The mandibles 

 are curved and slender at the tip, and project more than in other 

 Elaterinse; the labrum is more closely connected with the front; 

 the presternum is truncate in front, not at all lobed, and its 

 lateral sutures are straight, slightly oblique, not excavated in 

 front; the mesosternum declivous ; the middle coxte more conical 

 and prominent than usual, nearly contiguous ; the metasternum 

 is very acute in front; the coxal plates are dilated inwards, but 

 not suddenly, and differ slightly in form in the respective genera; 

 they are toothed at the origin of the thighs. The tarsi are simple, 

 and pubescent beneath; the claws are simple; the tibial spurs 

 are more developed than in other tribes. 



Two natural groups are obvious : — 



Front margined ; mandibles very prominent. Aphrici. 



Front depressed ; niandi])les not very prominent. Plastoceki. 



Gron]! I. — Aphrici. 



Aph.ricus califnrnicus, a small specijes having the appearance 

 of a slender Oardiophorus, is the only member of this group 

 known. The mandibles are long and slender, and project so as 

 to leave an open space between them and the front which is mar- 

 gined, and projects over the labrum ; the antenna; are moderately 

 serrate; the presternum is very slightly lobed; the sutures arc 

 single, and not excavated; the nn'ddle coxas are prominent; the 



