72 Mr. G. C. Champion's Revision of the Mexican 



Melsh.), being taken as the type, and others from Arizona 

 have since been added by Fall and Schaeiier. Its essential 

 characters, c^, are the simply incised lateral margins of 

 the prothorax (the notch sometimes wanting), the un- 

 divided tarsal claws, and the cleft seventh ventral segment. 

 The type, like that of Silis, has stout, serrate antennae 

 and small eyes. Polemius laticornis appears to have been 

 unknown to Gorham, but there are males of it from 

 Texas in the British Museum and others have been sent 

 me by Mr. Fall. The genus as here understood includes 

 various forms described under Discodon and Silis by 

 Gorham; P. basalis, Waterh., from Borneo, must belong 

 elsewhere. A Miocene species from Florissant (P. crassi- 

 cornis) has recently been named by Wickham. 



The Central American species may be grouped by their 

 (^ characters thus * : — 



I. Prothorax with or without a shallow notch 



on each side near the base, semicircular, 

 or with the margins feebly sinuate, more 

 or less truncate in front, leaving a portion 

 of the head exposed from above; an- 

 tennae serrate; tarsi each with one claw 

 broadly lobed at base : species Lampyri- 

 form Species 1-5. 



II. Prothorax with a conspicuous, rarely sub- 



obsolete, notch on each side, the margins 

 usually more or less angulate, lamellate, 

 or subdentate in front of the incision; 

 anterior tarsi and sometimes the others 

 also, with one of the claws lobed or 

 dilated at base : species Lampyriform 

 or Telephoriform. 



a^. Antennae stout, serrate Species 6. 



6^. Antennae more slender, serrate in some 



of the species Species 7-35. 



Species of doubtful position, females only 



known Species 36, 37. 



1. Polemius serricornis. 



Discodon serricorne, Gorh., Biol. Centr.-Am., Coleopt. iii, 

 2, p. 288, pi. 6, fig. 18 (?) (excl. var.). 



* Females only known of species 10 and 17. 



