86 NORTH AMERICAN 



considered not canaliculated ; on the contrary, however, if there be a 

 faint shadow extending along the middle of the disk, giving a decided 

 suspicion of a feeble impression in that direction, the student should 

 consult the tables given under subdivision j3. 



This minuteness of detail is rendered necessary, for the reason that 

 there is no natural division of species according to this character, and 

 forms gradually blend from one subdivision into the other, although 

 the character is nearly constant in individuals of the same species. 



The following tabular arrangement may be adopted at present : — 



Transverse carinae of abdomen 4-cuspid. 



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

 Large species, 4.0 mm. in length. 



First joint of the posterior tarsi one-third longer than the second. 



66. Virginia?. 

 First joint of the posterior" tarsi three-fourths longer than the second. 



67. texanus. 



Small species, 2.8 mm. in length 68. veil list US. 



Elytral suture longer than the pronotum. 



Abdominal segments as broad as the contiguous elytra ; sides parallel 



and continuous with those of the elytra 6ih Occident;! 1 i>. 



Abdominal segments narrower than the contiguous elytra ; sides more 

 or less convergent posteriorly. 

 Pubescence of abdomen long, fine, sparse, and recumbent, rather 

 conspicuous ; surface of elytra very irregularly and conspicuously 



channeled 70. pacific US. 



Pubescence finer, shorter, not at all prominent. 



Sides of prothorax undulated anteriorly 71. Obstrusus. 



Sides of prothorax more or less strongly and evenly arcuate ante- 

 riorly. 

 Longitudinal elevation of interocular surface distinct, somewhat 

 conspicuous. 

 Larger species, 3.4 mm. in length ; head small. 



Prothorax widest distinctly in advance of the middle. Arizona. 



72. arizonae. 

 Prothorax widest slightly behind the middle. Massachusetts. 



73. integer. 

 Smaller species, 2.8 mm. Head large. Florida. 



74. floridamis. 

 Longitudinal elevation of interocular surface almost obsolete, 



broadly and very feebly convex 75. colon us. 



Transverse carinae of abdomen tricuspid. 



Elytral suture in length equal to or shorter than the pronotum ; head 

 much wider than the elytra. 

 Antennal joints three, four, and five uniformly decreasing in length ; 



legs pale 76. lliailllliops. 



Antennal joints four and five equal in length ; form more robust and 

 more convex ; punctuation much coarser, deeper, and more distinct ; 

 legs almost black 77. gravid us. 



