Spiders of the genus mimic ants and ant-like wasps, living alongside and preying upon them.

The spider is most easily distinguished by the green-metallic sheen on its body, which is referred to in the species name.

Mexcala smaragdina is a jumping spider that was first described by the arachnologists Wanda Wesołowska and Glavis B. Edwards in 2012.

[2] The genus was a member of the tribe Heliophaninae alongside Pseudicius and Cosmophasis, which was absorbed into Chrysillini by Wayne Maddison in 2015.

The medium-high carapace is dark brown and covered in short delicate hairs that have an intense green-metallic shine.

[8] It is ovoid and shiny black, clothed in dark hairs that, like those covering the carapace, have a greenish golden shine.

The spider has long thin legs, the front ones generally black and the rearmost brown.

[14] It uses visual displays during courtship and transmits vibratory signals through silk to communicate to other spiders.