294 E. T. CRESSON. 



black, with a rather narrow white or yellowish annulus about the middle; me- 

 tathorax with the elevated lines sharply defined, the cen^;ral area quadrate, 

 rather large; w^ings hyaline, snbiridescent, nervures brown; legs black or 

 brown-black, strongly sericeous at base beneath, tips of the four anterior femo- 

 ra, and their tibire within, luteous, their tarsi brown; abdomen long, narrow, 

 shining, basal segment very slender, not rough at tip. Length 4 — 5J lines. 



Hah. — Massachusetts, (Ridings); Illinois, (Dr. Lewis). Five '^ s^jocimens. 

 This resembles ater, and may be the % of it. 



I. histricus. — %,- Large, dull black: faee white, with a broad black stripe 

 down the middle; narrow anterior orbits, dot at summit of ench eye, spot on 

 mandibles and jDalpi, except base, white; antennte more than half the length 

 of the body, very slender at tips, black, an imperfect yellowish annulus about 

 the middle, the basal joint white beneath ; thorax opaque, densely punc- 

 tured ; a sutural line in front of wing and a short line beneath, white ; scutel- 

 lum flat, white; metathorax rugose, the elevated lines prominent, the central 

 area transverse; wings uniformly dark fuscous, with a strong purple reflection, 

 nervures and stigma black, areolet subtriangular ; legs black, the two anterior 

 pair pale in front; abdomen elongate, depressed, opaque, very densely and fine- 

 ly punctured, less distinctly so at tip, first segment bicarinate, minutely acicu- 

 late; basal fove o of second segment very deep. Length 9 lines. 



Hab. — West Virginia, (Ridings). Allied to vittifrons, but quite distinct. 



I. puUatus may be tlie %, of subci/aneus. 



I. oruatipes. — %■ Shape and size of piiUatus ; black; orbits, face, elypeus, 

 mandibles and palpi yellowish-white; head not narrowed beneath; antennse 

 black, longer than head and thorax, basal joint whitish beneath; mesothorax 

 shining; tegulse, broad sutural line before and short line beneath each anterior 

 wing, scutellura and post-scutellum yellowish-white; metathorax confluently 

 punctured, the elevated lines well defined, the central area sublunate; wings 

 hyaline, nervures black; four anterior coxse white beneath, posterior pair black, 

 with a large white wedge-shaped spot beneath; four anterior legs white, their 

 trochanters, femora and tibiffi black behind; posterior legs black, the femora 

 with a broad white stripe beneath at base, their tibise with a white stripe be- 

 neath; tips of anterior tarsi black ; abdomen elongate, convex, dull black, first 

 segment shining, feebly sculptured. Length 6i lines. 



JIab. — West Virginia, (Ridings). Allied to pullatus, but easily separated by 

 the entirely wliitish face and difi'erently ornamented legs. 



I. sagus. — 9- Robust, deep black, shining; face broad, a narrow white line 

 on the upper half of the posterior orbits; antennae robust, with a rather broad 

 white or yellowish annulus about the middle; mesothorax and scutelium po- 

 lished, with scattered deep punctures, scutelium with a white spot at tip, some- 

 times a white dot before the wings; metathorax confluently punctured, the cen- 

 tral area subrotund; wings hyaline; legs robust, black, the tibife with a broad 

 exterior white stripe, tarsi brownish ; abdomen short, robust, oblong-ovate, 

 shining; first segment slender at base, dilated at tip, which is sjjarsely punc- 

 tured, but not rough ; second segment densely punctured, almost smootli at tip ; 

 remaining segn\ents irapunctured, except the base of the third segment, which 

 is sometimes sparsely punctured. Length 6 lines. 



%. Long, slender, deep black, sometimes shining; face and elypeus white or 

 yellowish-white, a narrow white line on the upper half of the ])osterior orbits; 



