94 AMERICAN COLEOPTERA. 



enables us to more readily and accurately separate the 

 species than has been possible. It seems to have entirely 

 escaped notice that in certain species of this group the seta 

 near the middle of the side margin of the prothorax is lack- 

 ing. The marginal setae are normally two in number, one 

 in the hind angle, and the other usually a little in advance of 

 the middle. In one species — laevigatum — there are two ad- 

 ditional setae close together at the anterior angle. The seta 

 in the hind angle is probably present in every species of the 

 genus, though I have not attempted to verify this. The 

 submedian seta is almost as universally present. Specimens 

 of course frequently occur with some or all of the setse 

 absent, but the presence of the setigerous punctures in the 

 margin in the vast majority of instances shows that they 

 have been accidentally lost. In three species of the present 

 group, however, the submedian seta is persistently lacking, 

 and the absence of a puncture in the margin shows that this 

 is the normal condition. Whether there are any other native 

 species of the genus which show this peculiarity I can not 

 positively say, but it seems very unlikely, since in the 121 

 species in my collection I find no other exception to the rule. 

 In the European litorale the submedian seta is also lacking, 

 and this enables us at once to separate it from the lacustre of 

 LeConte, which differs furthermore in the form of the men- 

 turn tooth. Lacustre must, therefore, be restored to specific 

 standing. It is indeed doubtful if the true litorale occurs at 

 all in this country. Collectors should carefully examine 

 their material in this group, and if native specimens are 

 found it would be well to publish the fact. Two new species 

 from the west coast appear in the following table and 

 litorale is included for comparison : 



Side margin of thorax without median seta. 



Mentum tooth elongate parallel, rounded or subtruncate at tip; 

 fourth dorsal stria sinuate ; size comparatively small ; form 



narrow and convex in sequale. 



Mentum tooth shorter and broader, sides converging in front, the 

 tip truncate and usually more or less emarginate. 

 Form slender and convex (size of incrquale) , fourth stria not or 

 very feebly sinuate, strial punctures coarse hesperum. 



