64 Mr. T. D. A. Cockerell on new 
with fairly dense and long white hairs. Tegule shiaing, tes- 
taceous. Wings hyaline, nervures and stigma dark brown; 
third submarginal narrowed not quite one-half towards 
marginal, Abdomen black, shiny, very finely punctate, with 
a very narrow band of white pubescence at the base of second 
and third segments. Hairs on tarsi more or less golden. 
Hab. College Farm, Las Cruces, N.M., April 16, 1895; 
one swept from Sisymbrium canescens (CkIl. 2572). 
‘his species will be readily distinguished by its large size, 
unarmed cheeks, black colour, and two narrow abdominal 
hair-bands. The enclosed portion of the metathorax is trun- 
cate behind, not rounded as in pectoralis. 
(3) Halictus pectoraloides, sp. n. 
9. This species had been confounded with HH. pectoralis, 
Smith, which it much resembles. Mr. Robertson has sent 
me an Illinois specimen of true pectoralis, and the following 
differences are at once apparent :— 
pectoralis. 
Mesothorax rather dull; punc- 
tures comparatively large and close. 
Parapsidal grooves obscure. 
Hair-patches at lateral bases of 
abdominal segments 2 and 3 ob- 
scure. 
pectoraloides. 
Mesothorax very shiny; punc- 
tures comparatively sparse. 
Parapsidal grooves very appa- 
rent. 
White hair-patches at lateral 
bases of abdominal segments 2 and 
3 very distinct. 
Third transverso-cubital — dis- 
tinctly bent. This is sometimes 
not very apparent. 
Sculpture of metathorax finer, 
Third transverso-cubital nervure 
gently curved. 
Sculpture of metathorax coarser. 
Among the New Mexico species pectoraloides is recognized 
by its black (not at all blue or green) colour, the shiny meso- 
thorax, and the patches of white pubescence at sides of abdo- 
minal segments 2 and 3. 
In the Mesilla Valley, N.M., pectoralotdes is very abundant. 
Sweeping Stsymbrium canescens on the College Farm, I got 
but two on April 12th; but on the 16th they were out in full 
force, and I captured eleven. While the pectoralotdes thus 
became more numerous, H. pruinosus, Rob., swept from the 
same flowers, diminished. Sweeping at random from the 
Sisymbrium, 1 got on April 12th ten prucnosus, on the 16th 
but four. Did the pectoralotdes drive them away ? 
Other dates for pectoraloides are:—Las Cruces, Aug. 5, 
1893; Las Cruces, July 18, 1893, 0n Solanum eleagnifolium ; 
College Farm, April 26, 1894, at tlowers of Lrigeron strigosus. 
