LAMPYRIDAE. 185 



Tribe III.— PHEHTGODINI. 



The characters of this tribe are that the head is not covered by 

 the thorax ; it is deeply immersed in the first, but less so in the 

 second sub-tribe ; the mentum is very small ; the antennae are 

 inserted in front of the eyes, under frontal elevations, and are 

 distant at base. The side pieces of the metathorax are wide, and 

 the inner margin is slightly curved as in Lampyrini. The mid- 

 dle coxa3 are contiguous, or very nearly so ; the trochanters are 

 moderate in length. The tarsi are uniformly pubescent beneath, 

 as in Lycini and Lampyrini. The females are not known to 

 me. 



Our two genera represent distinct sub-tribes : — 



Presternum well developed in front of coxse. Ptekotini. 



Presternum very narrow before the coxae. Phengodini. 



Sub-Tribe 1.— Pterotini. 



The singular Californian genus, Pterotus Lee, alone constitutes 

 this sub-tribe. The mandibles are long, slender, and prominent, as 

 in Phengodes ; the antennas are 11-jointed, with the joints 3 — 10 

 furnished internally with a flattened branch, three times as long 

 as the joint itself. The prosternum before the coxae is well de- 

 veloped, a character not seen in any other American genus of this 

 family. The maxillary palpi are cylindrical, as long as the man- 

 dibles, with the joints equal. 



P. obscuripennis, the only species known, is less than half an 

 inch long, reddish yellow, with the head, antennae (except the 

 base) and the elytra blackish. The female is unknown. 



Sub-Tribe 2.— Pliengodilii. 



The prosternum is very narrow in front of the coxos, as in other 

 Lampyrida3 ; the maxillary palpi are long and slender ; the lab- 

 rum is not very distinctly separated from the front ; the head is 

 prominent, and the gular region is not concealed. 



In the genus Phengodes, the third and following joints of the 

 antennae emit two very long, slender, and flexible, pubescent 

 branches from near the base ; the second and third joints are very 

 short. The elytra are one-third the length of the abdomen, and 



