Montana Field Guide

C. leachellus is a moderately large Crambid (25 - 27 mm wingspan) with medium brown forewings that have a wide longitudinal silvery white discal stripe which ends before the subterminal line. This stripe lacks a tooth below and is not cut by an oblique line. The forewings have a triangularly produced apex. There is a row of five dark spots in the subterminal line. The hindwing is smoky white. The cilia of both fore and hind wings are silvery metallic. Males are similar to females (Powell and Opler, 2009).

Shropshire and Tallamy (2025) provide a list, with synonymies, of 13,055 described native, exotic, and occasional straying Lepidoptera species of North America, north of Mexico; known but undescribed taxa, taxa with unresolved taxonomy, and excluded species are also included. The main manuscript includes links to supplementary materials, including a reference list for Lepidoptera of North America north of Mexico, and a filterable spreadsheet with information on taxonomy, synonymy, size ranges of species, distribution by state, province, and country with references, and host-plant Family and Genus associations with references.

C. leachellus adults have been collected in Alberta from August to mid September (Powell and Opler, 2009).

C. leachellus prefers grassland areas (Powell and Opler, 2009).

It is presumed that C. leachellus larvae feed on grasses (Powell and Opler, 2009).