38 UNIVERSITY OF COLORADO STUDIES 
white, and the anterior and middle femora strongly tinged with metallic blue; whereas 
Cresson says ‘“‘scopa pale ochraceous” and “legs black.’ It is a little bright steel blue 
species, about 8 mm. long, with more or less complete narrow pure white bands on the 
abdomen. Mandibles 3-dentate; hair of face all white; a pair of little orange tufts 
below anterior margin of clypeus; hair on inner side of tarsi light yellow. 
Osmia densa Cresson 
“‘Osmia densa Cress. MS., n. sp., Georgetown, July 8.” 
g. About 12 mm. long, with the head thrust forward. The specimen is evidently 
from a spider’s web, and curiously, has lost all its ventral scopa, except some black hairs 
(carrying pollen) on extreme sides. Much coarse black hair on face with finer white 
hair intermixed; hair of pleura white, of scutellum ai light, but dark hairs intermixed 
on mesothorax, some quite at hind border; legs not at all metallic; wings yellowish; 
abdomen with strong purple-blue tints, hind margins of segments not at all pallid. 
This is a genuine densa, but not the type; the latter was from Pike’s Peak. 
Halictus albitarsis Cresson 
‘* Halictus albitarsis Cress., type. Dallas.” 
é. About 6 mm. long; with head extended. Wings milky whitish, iridescent, with 
pale amber-colored stigma and nervures, the stigma quite brightly colored; antennz long, 
the flagellum bright ferruginous beneath; tarsi light yellow, with the apical joint more 
or less ferruginous; knees light; head and thorax olive-green, metathorax bluer; head 
rather long; labrum yellow except at sides; area of metathorax with longitudinal plice, its 
apical surface not sharp-edged laterally; abdomen dark rufopiceous. 
The original description was based on twenty-six specimens, and probably included 
more than one species. The color of the antenne and abdomen, as described, do not 
agree well with the specimen examined. 
Halictus rimosiceps Packard 
9. Quito, Ecuador. Nearly 1o mm. long; head and thorax dark olive green, thorax 
above dull and granular; metathorax with fine dark blue tints. Abdomen rufopiceous, 
slightly purplish, the fimbria fuscous. Legs dark, refescent. Wings hyaline, stigma and 
nervures dull reddish. Second submarginal cell approximately square, receiving first 
recurrent nervure just before its end; area of metathorax dull and granular, not at all 
ridged or grooved; hair of face and cheeks white, of vertex and front largely black; hair 
of thorax mixed black and light; eyes normal, little emarginate; abdomen without bands, 
and second segment not in the least vibrissate. Hind spur with two very large blunt 
spines, and a rudiment of a third. 
Augochlora nigroznea Packard 
g. Quito to Napo River, Ecuador. About 9 mm. long, belongs to group Sericei, not 
at all vibrissate, and the hind spur pectinate with a few large teeth. Face bluish-green, 
dullish and granular, with sparse punctures; eyes strongly emarginate; mesothorax dull 
green, blackish in middle; scutellum black; area of metathorax black, concave, with 
very fine longitudinal striation; the metathorax outside area is green, contrasting; pleura 
black; wings dusky, the costal region broadly suffusedly darker; second submarginal 
cell receiving first recurrent nervure near its end; abdomen black, with the hind margins 
