NORTH AMERICAN COLEOPTERA. 85 



The thorax, always narrower in front, varies in form as shown in 

 the sketches annexed. The basal marginal line is usually very dis- 

 tinct, rarely obliterated. 



The elytra vary in outline with the form of the species, and are 

 always confusedly ^^unctured, from densely to very sparsely, and from 

 coarse to very fine. In a series of moderate size the coarseness of 

 the punctuation is a variable quantity, and species cannot be safely 

 separated thereby. Those species in which there is color ornamen- 

 tation show the usual variation of color characters, but it is remark- 

 able that the extent of variation is so little in those species with the 

 apex more or less I'ed. 



The epipleurfe are horizontal and without fovese for the reception 

 of the knees. There is, however, a partial exception in eaurinus, a 

 species of the third group. 



The prostemum exhibits two modifications which are not so sharply 

 defined as to enable the characters to be used for systematic purposes 

 with certainty. In the species of the first two groups the prosternum 

 is either flat or slightly convex without the ridges, while in the next 

 two groups there is on each side a finely elevated line usually the 

 entirely length of the prosternum, the two convergent in front. 



The metasternum is usually smoother at middle than at the sides. 

 On each side behind the middle coxse there will be observed an ele- 

 vated curved line beginning at the inner edge of the meso-coxal 

 cavity curving backward and outward joining the suture between 

 tlie metasternum and its episternum. In the first two groups this 

 juncture occurs posteriorly to the anterior third of the suture, while 

 in the next two groups the arc is more nearly complete the line joining 

 the suture near the front, very often at the angle. 



The abdomen is said to be composed of five segments, but in the 

 first two groups there are six very distinct segments in both sexes, 

 while in the next two groups the occurrence of the sixth segment is 

 not frequently observed. Fearing that I had only females of the 

 first two groups for examination I directed the attention of Mr. H. 

 C. Fall, of Pomona, Cal., to the species which he might obsei've and 

 from specimens collected in coitu it has been found that the sexes 

 are alike in the number of segments and the male has no apical 

 impression. The suture separating the first two ventral segments 

 varies greatly in distinctness, being at times nearly obliterated at 

 middle and sometimes as distinct at middle as at the sides. Mr. 

 Blackburne (Trans. Royal Soc. South Aust. xv, 1892) restricts the 



TRANS. AM. ENT. SOC. XXII. APRIL. 1895. 



