COLEOPTERA. 37 



Head wide and robust, as broad as or broader than the elytra. 



Legs black... 26. iiitrusus. 



Legs rather pale piceous-brown 27. ei'ytliropus. 



Head small, narrower than the elytra; punctuation much closer. 



Punctures of abdomen extremely closely crowded ; surface opaque. Head 



less than twice as wide as long. Colorado i 28. rugifer. 



Punctures of abdomen less crowded ; interspaces distinctly visible, shin- 

 ing. Head distinctly more than twice as wide as long. White Moun- 

 tains, N. H 29. auastomozans. 



§§§'§ 



The following table is simply intended as an indication of the 

 approximate position of the species, and is only to be depended upon 

 as an aid to the consultation of the descriptions : — 



Elytral suture in length equal to or shorter than the pronotuin. 



Prothorax wider than long, scarcely narrower than the head. Form 



robust, depressed 30. slioslionis. 



Prothorax narrower than long. 



Large species 4.0-4.2 mm. in length, slender. Vancouver Island. 



31. insularis. 

 Species not exceeding 3.1 mm. in length. 



Robust, depressed ; elytral sculpture very coarse. Washington Terri- 

 tory 32. vexatus. 



Much more slender, rather convex or sub-cylindrical ; elytral sculp- 

 ture rather fine and even. Massachusetts. 

 Prothorax widest before the middle. 



Species 2.S-3.0 mm. in length ; head large ; interocular surface 



rather deeply excavated 33. Scliwarzi. 



Species 2.1-2.3 mm. in length ; head small. 



Longitudinal elevation of interocular surface distinct ; sides of 



elytra distinctly divergent posteriorly 34. pauper. 



Longitudinal elevation obscure ; sides of elytra almost exactly 



parallel 35. silbtilis. 



Prothorax widest behind the middle 3b'. indigeilS. 



Elytral suture longer than the pronotuin. 

 Species 3.0 mm. or more in length. 



Longitudinal elevation of interocular surface indistinct or nearly obsolete. 

 Canaliculation of prothorax very short, rather conspicuous, situated 



behind the middle. Oregon 37. simplex. 



Canaliculation very feeble, extending nearly the entire length of 

 the pronotum. District of Columbia, Pennsylvania, Alabama. 



38. vie in us. 

 Canaliculation excessively feeble, being reduced to a simple erosion, 



situated just behind the middle 39. iligratlis. 



Longitudinal elevation of interocular surface distinct. 



Large species, about 4.0 mm. in length 40. neglectllS. 



Smaller species, not exceeding 3.3 mm. in length. 



