44 MEMOIRS ON THE COLEOPTERA 



by about twice their widths. Length 1.9-2.0 mm.; width 1.2 mm. 

 Michigan (Detroit). [L. (Limnichites) olivaceus Csy. nee Lee., 

 Ann. N. Y. Acad., 1890, p. 154] huronicus n. sp. 



The remarkable median modification of the pronotum, either 

 by a short transversely arcuate series of tumid punctures, as in 

 the larger species punctatus and huronicus, or by shorter more feeble 

 subtumid barely traceable and not specially punctured lines in 

 most* of the smaller species of this genus, is a character sometimes 

 traceable in a greatly modified form in the genus Eulimnichus, 

 and was first discovered by Dr. Sharp in examining some Central 

 American species, where it becomes strikingly developed; it is 

 therefore a somewhat general character, though as noted thus far 

 not affecting any other groups than Limnichites, Eulimnichus, 

 Phalacrichus and Limnichalia; it cannot be correlated with any 

 other special modification, either of the pronotum or prosternum, 

 and is probably a vestigial character of some sort. Its presence 

 in only the four genera mentioned does not indicate generic identity 

 of those four groups, for the differences in the front, eyes and an- 

 tennal insertion between Limnichites and Eulimnichus are far more 

 significant than those distinguishing either of these genera from 

 some others, such as Lichminus, not possessing this special pronotal 

 character. 



In my former revision of this group I reinstated olivaceus Lee., 

 on what now prove to be some erroneous or unwarrantable assump- 

 tions, for, on reading the original description of olivaceus, I observe 

 the statement that "the punctures are larger" than in punctatus 

 though this proves to be largely fanciful, while in olivaceus 

 Csy., nee Lee., named huronicus above, the punctures are very 

 much smaller than in punctatus. Again under the original de- 

 scription of obscurus (1. c., 117) appears the statement "less densely 

 and more finely punctured than those above described [olivaceus 

 and punctatus}, the punctures being more distant from each other 

 than their own diameters." It is to be inferred from this that the 

 punctures in olivaceus and punctatus are separated by not more 

 than their own diameters, a condition which is known to be exactly 

 that existing in punctatus, while in huronicus the punctures, which 

 are much smaller and feebler, are separated by between two and 

 three times their diameters. Furthermore there can be no jus- 



