Adult males have an iridescent cobalt to cerulean blue gorget with a narrow buffy gray margin.

They have medium brownish gray underparts with some greenish bronze iridescence on the sides of the breast.

The tail is black with some faint indigo iridescence and white tips on the outer two pairs of feathers.

It is found in Mexico's Sierra Madre Oriental and central plateau as far south as Oaxaca.

L. c. basophils is found in southeastern Arizona and in the northwestern Mexican states of Sonora, Chihuahua, and Durango.

L. c. phasmorus is positively known only from the Chisos Mountains of southern Texas, where it breeds, but its non-breeding range is not known.

In Arizona it is found in the "sky island" mountain ranges, seldom below 1,300 m (4,300 ft) of elevation.

The populations in central and southern Mexico are thought to withdraw to lower elevations in winter but this movement has not been fully defined.

The species fed from vary considerably across the bird's wide north–south and elevational ranges.

In the breeding season (especially early when flowers are scarce) and in winter it also feeds on small arthropods.

In winter it also feeds on sap from wells created by the Red-naped sapsucker (Syraphicus nuchalis).

[7] The male song differs in several respects from that of oscine birds in that it uses sharp atonal forceful trills and clicks, and has an unusually large vocal range of 1.8 to 30 kHz.

[6] The bird also uses ultrasonic vibrations which are not for communication, but possibly serve to flush out and disorient its insect prey.

However, in the northern part of its range it is uncommon and found in only a few narrow canyons, so damage to those areas by fire or human alteration may affect it.