36 MEMOIRS ON THE COLEOPTERA 



as a rule, possesses positive and constant features which are easily 

 grasped when under adequate optical power, and it may as well be 

 stated here that, as in the case of other minute Coleoptera, the 

 binocular microscope with powers of 25 to 45 diameters, as given by 

 1-5 or .75 inch objectives, is virtually essential as the chief working 

 tool in the study of the Phalacridae. The hand lens is almost 

 useless, except in forming a general idea of bodily form or color 

 and other such general characters; a conception of outline is best 

 conveyed by a large lens of very small power. 



The numerous species of Phalacms are uniformly shining black 

 throughout above, and so this character will not be repeated in the 

 descriptions. They generally have a stout convex body, and the 

 apically descending prosternal process and moderate hind tarsi, 

 with the moderately elongate second joint longer than the first, as 

 in Olibrus, but the genus is distinguished primarily from Olibrus 

 by its stouter build, more developed head in many cases, blacker 

 coloration on the whole, different character of elytral punctuation 

 and, especially, by the very large scutellum. The elytra have more 

 or less evident series of feeble punctures, which are always at least 

 to some degree transversely lunate postero-laterad, but have only 

 a single discal stria, which is near the suture and abbreviated basally. 

 Impressed striiform lines are frequently observable in certain species, 

 but I am unable to say whether this is always an adventitious char- 

 acteristic or not, though it is so treated below. The species in my 

 collection are the following: 



Elytra polished and devoid of reticulation throughout 2 



Elytra polished basally, reticulate posteriorly 15 



Elytra with minute reticulation of very fine lines throughout, this ground 

 sculpture never however producing more than a very feeble aluta- 



ceous lustre 1 6 



2 Elytral punctures very small throughout, never more than feebly 



dilated postero-laterad 3 



Elytral punctures small and feeble discally, but becoming broadly lunate 



postero-laterad 1 1 



3 Species of the Atlantic regions 4 



Species confined to the Rocky Mountain system 5 



Species occurring only west of the Sierras in California 7 



4 Form broadly oval, slightly tapering posteriorly, very convex, with a 

 varnish-like polish throughout above, the entire under surface and 

 legs black, the antennae black, with a feeble piceous tinge, the two 

 basal joints obscure testaceous; funicle rather long; third joint fully 

 as long as the next two, which are each fully twice as long as wide; 



