Length: 11.5 - 14.0 mm
In Alchisme grossa, the pronotum is high and angular, with the point of the angle projecting slightly forward. The median ridge is reddish and has dark spots. A prominent lateral horn juts out from each of the humeri.
The eyes are eliptical, and the ocelli are closer to each other than to the compound eyes (Creão-Duarte and Sakakibara, 1997).
Members of this genus are encountered from Mexico south to Argentina and Chile. Alchisme grossa has been reported from Colombia and Ecuador.
Members of this genus are not associated with ants.
Photo location: Tandayapa Valley, Ecuador.