and Central American Telephorinae. 99 



the elimination of all those included in it by Gorham with 

 one or more of the tarsal claws cleft in male, should perhaps 

 be referred to more than one genus ; but I am unable to 

 find any structural characters upon which to divide them. 

 There is every gradation in the form of the armature of 

 the margins of the prothorax, from long lobes to short 

 teeth, and the species here included under Section II 

 would be equally well placed under Polemius, in which 

 the lateral margins are, at most, simply notched or inter- 

 rupted in the male, i. e. as in Discodon. Ditemnus (type 

 Silis lepida, Lee. = Canfharis hidentata, Say) is nearly 

 related to the European Silis ruficollis, F., and the Mexican 

 S. longidens to the European S. nitidtda, F. The single 

 species referred to Section III, S. chalyheijiennis, Gorh., 

 will doubtless, sooner or later, have to form the type of a 

 separate genus. Silis, as understood here, may be defined 

 thus : prothorax with the lateral margins incised or con- 

 stricted at or towards the base, and sometimes {Ditemnus) 

 deeply incised at about the middle also, the margins more 

 or less lobed, lamellate, or dentate, the lobes often imbricate, 

 the tarsal claws uncleft, and the seventh ventral segment 

 divided down the middle, in ^. The typical forms have 

 small eyes and rather stout serrate antennae, but this 

 definition does not apply to many species placed under 

 Section II. We are indebted to Mr. H. C. Fall for specimens 

 of several of the described N. -American representatives of 

 the genus for comparison. 



The Central American species of Silis may be grouped 

 by their ^ characters thus * : — 



Silis. 



I. Prothoracic margins deeply bi-incised, and 

 also strongly bi- or trilobed. 



a. Lateral lobes long, convergent : species 



elongate, black, Telephoriform . . . Species 1. 



b. Lateral lobes lamelliform, directed back- 



wards or imbricate : species smaller and 



less elongate. 

 a^. Inner anterior tarsal claw with a stout 

 angular lobe at base : species Malachii- 

 form, black Species 2. 



* Females only known of species 18, 34. 



