282 MEMOIRS ON THE COLEOPTERA 



of the elytra are much more developed. From comonforti Mars., 

 it differs in the more unequal thoracic lobes, sparser elytral punc- 

 tures and deep black coloration, among other characters. 



Plegaderus pygidialis n. sp.- Oblong, black, polished, the legs rufous; 

 head coarsely, closely punctate; prothorax a third wider than long, the 

 parallel sides evenly rounding apically, the lateral sulcus deep, not very 

 broad, the lateral surface strongly and densely punctate; disk divided 

 at anterior two-fifths by a deep and abruptly defined, feebly sinuate 

 sulcus, the anterior lobe finely, strongly and closely, the posterior sparsely 

 and strongly, and toward base coarsely, punctate; elytra shorter than 

 wide, a fourth longer than the prothorax, subangularly dilated at the 

 sides behind the base, thence moderately and arcuately narrowed pos- 

 teriorly; surface rather coarsely, deeply and evenly punctate, the punc- 

 tures somewhat close but separated by more than their diameters; 

 suture cariniform except in basal fifth, where it becomes abruptly 

 perfectly flat; two short oblique basal striae are distinct; pygidium small, 

 flat, with extremely coarse and polygonally crowded punctures; pro- 

 sternal space between the sulci divided far behind the middle by a very 

 broad and opaque sulcus, the posterior lobe small and narrow, in slope 

 gradually merging anteriorly into the broad sulcus. Length 1.2 mm.; 

 width 0.6 mm. Arizona (Williams), -Wickham. A single example. 



One of our smallest species and very distinct in the polished 

 black surface, coarse punctures, which are well separated on the 

 elytra, and the very densely and coarsely cribrate flat pygidium. 



Sayi Mars., is one of the most isolated of our species in the 

 unequal punctures of the two pronotal lobes, coarse, close elytral 

 punctures and very coarsely, closely cribrate metasternum; it is 

 rare, but has been taken by Mr. Frost at Monmouth, Maine, and 

 I have recently received a specimen through the kindness of Mr. 

 Carnochan. The large flat metasternum in sayi has a coarse deep 

 stria along the median line from the very short, anteriorly sinuate 

 mesosternum, nearly to the abdomen. 



Plegaderus sulcatus n. sp. Ovoidal, convex, polished, black, the 

 under surface and legs rufo-castaneous; head somewhat concave trans- 

 versely, strongly and rather closely punctate; prothorax distinctly nar- 

 rower than the elytra, only a fourth or fifth wider than long, expanded 

 slightly at base, the sides rounding in nearly apical third, the lateral 

 surface densely and deeply punctate and having, along the marginal line, 

 a deep smooth sulcus, which is coarse basally, disappearing anteriorly; 

 inner sulcus deep; disk divided by a deep sinuate sulcus slightly before 

 the middle, the anterior lobe finely and closely, the posterior almost 

 equally finely except basally but very sparsely, punctate; elytra large, 

 convex, but little shorter than wide, fully a third longer than the pro- 

 thorax, distinctly but obtusely inflated behind the base, the sides strongly 



