12 AMERICAN HYMENOPTERA. 



1^ .—AntenniE elongate, entirely reddish testaceous, distinctly longer than head 

 and thorax united, joints 4-7 of flagellum slightly prominent beneath: clypeus 

 scarcely produced as in 9 ; middle segment more coarsely sculptured than in 9 

 the petiole of abdomen somewhat longer and slenderer : coloration and venation 

 almost as in 9 ■ Length 9 mm. 



Philadelphia, Pa., August 4 (C. W. Johnson) ; New Hampshire : 

 Mt. Washington (Packard). Three specimens. Easily distinguished 

 by the bright red abdomen and venation. According to Packard 

 the last two segments of abdomen in his specimen were black. 

 5. Group arg-entifrons. 



Pygidium ( 9 ) broad, not much narrowed apically, closely punc- 

 tured, not depressed. Petiole of abdomen varying in length and 

 form in tiie various species. Both recurrent veins received by the 

 second submarginal cell. Cubital vein of hind wings originating 

 distinctly before the apex of the submarginal cell. Tibiae spiuose. 

 Antennae ( S ) elongate or subclavate. 



15. Psen argeiitifroiis Cress. 



Mimem arfjeiififnons Cresson, Proc. Ent. Soc. Pbila. v, 487. 1865. 



9. — Head rather finely and evenly, though not very closely, punctured : face 

 and clypeus densely silvery, the clypeus with a transverse prominence just before 

 anterior margin, the latter strongly sinuous, in the middle having the appearance 

 of being tridentate ; space between hind ocelli about equal to that between them 

 and eyes; flagellum fulvous beneath, first joint about one-quarter longer than 

 second ; in length the antennpe are greater than the head and that portion of the 

 thorax anterior to the middle segment; dorsulum with rather strong, separated 

 punctures, the mesopleurai more subtilely punctured, striated basally and apically ; 

 enclosure of middle segaient large, with no central area, lateral rugae coarse, the 

 apical portion with transverse rugse ; posterior surface of middle segment rugoso- 

 reticulate, depressed medially; the sides at base strongly striated; tarsi testa- 

 ceous; abdomen with apex of first segment, the second entirely and most of third, 

 reddish : petiole rather flat above, depressed at apex, furrowed near the sides but 

 not deeply, in length somewhat longer than hind femur, on the sides with two 

 wide, shallow furrows; second submarginal cell not narrowed one-half above. 

 Length 9-10 mm. 



'J, . — Head closely punctured ; antennge elongate, longer than head and thorax 

 united; middle segment much more coarsely sculptured than in 9' th^ rugae of 

 the enclosure irregular; tibiae and tarsi reddish; petiole more deeply sulcate, and 

 with a tra(-e of a medial furrow above apically. Length 8-9 mm. 



Colorado. The specimens from Illinois, referred to by Packard, 

 probably represented another species, and pei'haps Cressoiiii. 



16. Psen Cressoiiii Pack. 



Mimesa Cressonii Packard, Proc. Ent. Soc. Phil, vi, 405, 9- 1867. 



Mimesa deniicalata Packard, ibid. 406, % , 1867. 

 9. — Head more distinctly punctured than in argentifrons ; face and clypeus 

 sparsely silvery ; clypeus convex, strongly punctured, long, its length equal to 

 decidedly more than half its breadth, fore margin broadly subtruncate ; space 



