384 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



over the plearse; surface moderately convex on the anterior lobe, flatter 

 posteriorly, the transverse line distinctly impressed, irregularly punc- 

 tate, terminating before the siibmargin in a distinct fovea, the surface 

 behind the line and near the lateral margins irregularly punctate ; the 

 exterior suture with a series of remote, coarse punctures, and remotely 

 ciliated; anteriorly and posteriorly destitute of punctures, particularly 

 next the hind margin ; humeri a little prominent, a little prolonged for- 

 ward in a ridge, exterior to which the side is high and steep. Legs 

 rufo-piceous ; the anterior tibise moderately expanded 5 the outer edge 

 with about ten rather long, curved spines; the upper surface trans- 

 versely furrowed ; the tip with three or four long, straight spines, 

 and the inner margin near the apes with a long, slender, oblique one ; 

 posterior tibise long, slightly curved, closely set with long black spines ; 

 tibise ocherous or ferruginous. Scutellum a little convex at base, 

 depressed behind the middle, coarsely, remotely punctate from behind 

 the base almost to the tip, the lateral submarginal line deeply impressed, 

 finely punctate. Corium of medium width, the surface irregularly rugu- 

 lose, finely remotely punctate, and with coarser punctures on the inner 

 seams on and near the clavus ; the costal margin with three or four pits 

 carrying bristles ; membrane a little brownish. Venter smooth, irapunc- 

 tate, the posterior edges of the segments each side with very minute 

 teeth; the connexivum uneven, irregularly indented. 



Length 7-8 millimeters. Width at base of pronotura 3^-4^ millimeters. 



Inhabits Massachusetts, Connecticut, iSTew York, Pennsylvania, Mary- 

 land, and the Southern States as far west as the middle of Texas. One 

 specimen from Matamoras, Mex., agrees with the form as seen in the 

 Atlantic region. It is also the JEtlms rohertsoni of Fitch's MSS., from 

 Indifln Territory, as I know from an examination of a specimen in his 

 collection, as also from the determination by Dr. Si^noret, to whom 

 Dr. Fitch sent specimens. 



It is of importance to record that this species varies very much in some 

 of its structural features. In a few specimens, which were normal in other 

 respects, the margin of the clypeus was scalloped each side of the mid- 

 dle, and emarginated in front of the tylus. The second and third joints 

 of the antennae are sometimes equal ; at others, either may be longer than 

 the other. The ostiolar canal and the plate to which it is attached vary 

 in length and width, and are often ragged on the posterior margin. Two 

 specimens have been examined by me, which had the ostiolar piece of 

 one side normal, and on the opposite side long, triangular, and jagged. 

 Usually, there are but three pits and bristles on the costal margin, but 

 occasionally there are four, and in one specimen I noticed five. 



2. P. rngifrons. 



Cydnus rugifrons H.-Schf., Wanz. lus., v, p. 97, fig. 547. 

 Oval, piceous-black. Head a little broadly rounded in front, the ex- 

 terior margin broadly recurved, remotely ciliated ; the surface flat, but 



