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



57. Discodon mexicanum. 



Silis mexicana, Pic, Bull. Soc. Ent. Fr. 1909, p. 346. 



Hab. Mexico, {coll. Pic). 



Pic describes this insect as near Silis praemorsa, Gorh. 

 (— ^ of aS. lycoides), differing from it in having the pro- 

 thorax but little incised laterally and the head more 

 broadly black : elongate, rather shining, black ; the head 

 in part, the sides of the prothorax, and the humeral callus 

 flavous ; antennae moderately long, slightly thickened at 

 the base, attenuate at the apex; prothorax transverse, 

 with the sides subarcuate anteriorly, almost straight 

 posteriorly, and feebly emarginate behind ; elytra broader 

 than the prothorax, long, dilated towards the middle, 

 densely, rugulosely punctate. 



The sex is not stated, and as the colour of the elytra is 

 variable, and of no value as a specific character, in these 

 Lj^ciform insects, it is impossible to certainly identify 

 Silis mexicana from the incomplete description : it may 

 be a male of D. {Silis) varians, or of an allied form of which 

 we have various females from Mexico, etc., left doubtfully 

 placed by Gorham under S. varians, lycoides, and nodicollis. 

 Five of these females (from Toxpam, Jalapa, Cordova, 

 San Juan, and San Geronimo) have the apical half or more 

 of the elytra, and the suture thence to the base (in part or 

 entirely), a dorsal vitta on the prothorax, and the head 

 in part, black ; the mandibles long and abruptly bent ; 

 the antennae rather short, stout, greatly dilated from the 

 third joint, tapering towards the apex; the prothorax 

 transverse, subquadrate, uneven, the margins dilated, 

 reflexed, and trisinuate (appearing subangular anteriorly), 

 the hind angles prominent ; the elytra broader than the 

 prothorax, dilated posteriorly, rugose, and distinctly 

 costate. Till these 9 forms can be obtained with their 

 respective males from their special localities it is impossible 

 to locate them correctly. 



58. Discodon serrigerum. (Plate VIII, fig. 58, 

 prothorax, ^.) 



Silis serrigera, Gorh., Biol. Centr.-Am., Coleopt. iii, 2, 



..p. 292(<^$). 

 Silis varians, Gorh., loc, cit. p. 92 (part.). 

 Silis varians, var., Gorh., loc. cit. pi. 6, fig. 1 ($). 



