March, 1896.] FOX, NORTH AMERICAN SPECIES OF NySSON. 
11 
Pygidial area narrower, rounded at tip, longitudinally rugoso-punctate; lateral 
spots of first dorsal segment confined to apical portion of the segment, 
transverse. aequalas. 
8. Clypeus bituberculate at apex ; punctuation of the head and thorax very coarse, 
almost rugose (medial and hind femora more or less red) ... .compactus. 
Clypeus not tuberculate; punctuation strong, but rather close and not rugose.9 
9. Abdomen not at all red.10 
Abdomen with the two basal segments more or less reddish (punctuation of head 
and thorax very close, appearing granular; punctuation of abdomen subtile). 
rusticus. 
10. Punctuation of head and dorsulum distinctly separated, that of the abdomen 
strong and very distinct .. . lateralis. 
Punctuation of head and dorsulum, particularly the former, very close, that of 
abdomen rather subtile, most distinct on first segment. fidelis. 
11. Scutellum distinctly margined laterally.12 
Scutellum not margined laterally.„.15 
12. Abdomen not at all reddish.13 
Abdomen reddish basally. 14 
13. Basal enclosure of middle-segment with coarse, irregular ridges, thereby mak¬ 
ing the enclosure reticulate; abdominal punctures strong, but not very deep. 
opulentus. 
Basal enclosure of middle-segment with the ridges regular, longitudinal on 
basal two-thirds, then oblique; abdominal punctures deep. mellipes. 
14. Scutellum coarsely rugoso-punctate; wings clear; a yellow line on pronotum 
and scutellum. bellus. 
Scutellum with coarse, longitudinal folds; wings subfuscous; no yellow on pro¬ 
notum or scutellum (punctuation of head and dorsulum unusually coarse). 
basilaris. 
15. Black, with pale markings; a divided tubercle between the ocelli; punctuation 
of head and thorax strong and separated .. albomarginatus. 
Black, with abdomen red ; space between ocelli not tuberculate ; punctuation of 
head and thorax very close and rather fine. bicolor. 
Males. 
Hind tibiae more or less serrated; last dorsal segment 4 dentate.2 
Hind tibiae not serrated; last dorsal bidentate.3 
2. Legs red. texanus. 
Legs black. fuscipes. 
3. Second ventral segment truncate at base, viewed from the side almost forming a 
right angle. spinosus. 
Second ventral segment otherwise formed.4 
4. Submedian cell (anal area) terminating beyond or at the origin of the cubital 
vein.5 
Submedian cell terminating before the origin of the cubital vein. 13 
5. Last dorsal segment ciliated between the teeth .6 
Last dorsal segment not ciliated between the teeth...7 
