66 Mr. T. D. A. Cockerell on new 
An Halictus taken at Las Cruces on August 14, 1893, 
differs from subobscurus in having the marginé of the segments 
very distinctly testaceous, after the manner of lusorius, Cr. 
I doubt whether it is a distinct species ; it is not Jusordus. 
(5) Halictus semiceruleus, sp. n. 
@?. Length about 53 millim. Head bronzy green, thorax 
dark blue, abdomen black. Head rather narrow; face some- 
what longer than wide, strongly punctate; clypeus blackish 
at end, mandibles more or less reddish. Cheeks strongly 
bluish. Flagellum only slightly brownish towards end. 
Mesothorax shiny, with large punctures; median groove deep 
and distinct, parapsidal grooves obscure. Scutellum with 
large, rather sparse punctures, and between the punctures 
microscopically striate. Postscutellum with rather long scat- 
tered hairs. Enclosure of metathorax finely rugulose, sub- 
reticulately wrinkled, bounded by a raised but not carinate 
border, rounded, not truncate, behind. Sides of metathorax 
and pleura with whitish hairs. 
Tegule testaceous. Wings hyaline, nervures and stigma 
pale honey-yellow, subcostal nervure black. Third submar- 
ginal squarish, little narrowed towards marginal; third 
transverso-cubital and second recurrent nervures very faint. 
Legs dark; tarsi (except first joint) reddish. 
Abdomen black, with a greenish reflection ; sides of seg- 
ments 1 and 2 and whole of dorsal segments 3 and 4 thinly 
covered with short whitish hairs. 
Hab. Santa Fé, N.M., June 20, 1894 (CkIl. 987). 
The following table has been prepared to separate the 
species liable to be confused with semicwruleus :— 
Mesothorax blue ; tegule not punctured ; stigma pale 
BOTS YE Sie ja eie's.2 ale oxena eet ee eee en senuceruleus, Ckll. 
Mesothorax green (or blue-green, with tegulee punc- 
tured, in palustris). 
First two abdominal segments constricted at apex ; 
abdomen dark seneous ..........00s0eeeees coactus, Cress. 
Abdomen normal. 
Tegule punctured; metathorax short, broad, 
strongly tromcate: <9. 5 s\eerasm cman eaves ont palustris, Rob. 
Tegulee and metathorax normal. 
Mesothorax dull: dark blue-green .... floridanus, Rob. 
Mesothorax dull: brassy green ...... pilosus, Smith. 
Mesothorax more or less shiny. 
(Robertson says the mesothorax of prauinosus is not shiny ; 
it is so in our New Mexico form, which otherwise agrees 
with the description, and which has been seen by Mr. Robert- 
son.) 
Face and metathorax bluish or blue-green, . pruinosus, Rob. 
Face and metathorax brassy green ...., wo» ephyrus, Smith. 
