I found this interesting Poecilus in central Arizona at night immediately following a 2-3 hour violent rainstorm. It has a black surface with violet reflections and metallic green borders.
This individual keys out to chalcites in Lindroth's monograph by shape of the pronotum. I believe this could be a different species for the following reasons:
1. Habitat. P. chalcites is a primarily eastern species. This specimen was collected on a high elevation cliff top with many cactuses, desert broom, and other typical Arizonan scrub vegetation on otherwise barren soil.
2. Distribution. Bousquet remarks chalcites' occurrence in Arizona is doubtful. Furthermore, most primarily eastern species that reach Arizona only make it to the southeast corner of the state.
3. Color and morphology. This specimen is about 14.0 mm, nearly 1.5 mm larger than my largest example of chalcites. The color is different than any chalcites I've seen. Most convincingly, the sides of the entire thorax are smooth in this specimen, while they are coarsely punctured in all nine examples I have of chalcites from Illinois, Kansas, Kentucky and Nebraska. The abbreviated scutular striae are also shorter than in my specimens of chalcites.

Lindroth does not include Arizonan species mexicanus or texanus in his work. While within Arizona, Bousquet only recognizes those species to occur in southeastern Arizona.
I only collected this one individual and have not spent a great deal of time with it under the scope. I can't remember if I have ever been able to find the species descriptions of mexicanus or texanus either. Help much wanted.