NO. 1988. STUDIES OF NORTH AMERICAN WEEVILS— PIERCE. 383 



Between the t3T)es of these two genera there is considerable differ- 

 ence in facies, but the writer has been unable to find a single generic 

 character to separate them. The descriptions are almost identical 

 except as to the direction of the first abdominal suture, and the 

 mucronation of the hind tibiae. Neither of these characters can be 

 used as they vary in specimens of the same series of the same species. 

 The genus as here presented is therefore a reconstruction based upon 

 the characters which are presented in the table of genera of this tribe. 

 The nasal plate in this genus is depressed, but poorly defined. 



Table of species of Melamomphus. 



I. Apex of posterior tibiae with a double row of spines forming an inclosed disk. 



1. Anterior tibiae, only, denticulate. 



aK Species elongate. Prothorax strongly granulato-tuberculate, the tubercles 

 punctured; beak very roughly sculptured. 

 6'. Species black; vestiture black; pubescence dense and black; nasal plate 

 triangular, not strongly defined, basally emarginate; humeral angles 



rectangular, broader than base of prothorax (Nevada) niger Horn. 



b^. Species black; vestiture brown; pubescence dense and brown; nasal plate 

 crescent form, not strongly defined; humeral angles entirely obliterated, 



not broader than base of prothorax (California) elongatus Horn. 



0?. Species less elongate, more robust. 

 c'. Prothorax strongly granulato-tuberculate, the tubercles punctured; beak 

 very roughly sculptured, 

 d'. Humeral angles entirely obliterated; species brownish red; nasal plate 



triangular, emarginate (California) sordidus Horn. 



d-. Humeral angles small, wider than prothorax at base; species black, 

 with brownish vestiture; nasal plate crescent shaped (California), 



dedduus Horn, 

 c^. Prothorax not strongly granulato-tuberculate. 



e^ Species black, humeral angles small, but wider than prothorax at base; 

 vestiture silvery, pubescence moderately long; nasal plate semielliptical, 

 basally emarginate; posterior tibiae mucronate at tip (Washington), 



nigrescens, new species. 

 e^. Species reddish-piceous, humeral angles minute; vestiture brownish, 

 cinereous, pubescence moderately long; nasal plate hemispherical, ill- 

 defined, basally emarginate; alternate intervals sometimes clothed with 

 lighter vestiture; hind tibise mucronate in males, mutic in females, first 

 ventral suture straight in males, arcuate in females (Montana, Washing- 

 ton), 



luteus Horn. 



[tessellatus Casey probably belongs here.] 



2. All tilna; denticulate; prothorax with punctured tubercles. 



a'. Humeral angles rectangular; nasal plate subtriangular, poorly defined, strongly 



emarginate (California, Vancouver) mucus Horn. 



a2. Humeral angles obliterated; nasal plate subtriangular, poorly defined , strongly 

 emarginate; alternate intervals sometimes clothed with lighter vestiture 



(Montana, California) alternatus Horn. 



[granulatus Casey probably belongs here.] 



II. Apex of posterior tibiee with a single row of spines; anterior and median tibise 



denticulate; prothorax covered with punctured tubercles; humeri angulate; 



nasal plate crescent shape ciliatus, new species. 



