Field Guide Descriptions: Covell (1984); Beadle and Leckie (2012) | Online Photographs: MPG, BugGuide, GBIF, BOLD | Technical Description, Adults: Forbes (1923) | Technical Description, Immature Stages: Wagner (2005); Wagner et al. (2011) | |
Adult Markings: Adults are unmistakable: dark umber to lustrous coal black over the basal and medial portions of the wings, with an undulating, contrasting yellow-brown border along the outer margin on both the fore- and hindwings. Other blackish Zales lack this contrasting edge. Scale tufts on the thorax and abdomen and raised scales on the outer border give horrida a highly sculpted, ornamented appearance; despite its somber coloration, it is one of our more gaudy species of moths. |
Adult ID Requirements: Unmistakable and widely known. |
Immatures and Development: Caterpillars are a nondescript grayish to reddish (see photos in Wagner et al., 2011) and are probably best distinguished by their host plants, horrida being the only specialist among the Zales on Viburnums (but some of the host plant generalists, e.g., Z. lunata, might also occasionally be found on Viburnums). |
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants. |