The larva of A. barretti is described for the first time and compared with those of A. harknessi from Mexico and A. joergenseni from Argentina. Based upon larval characters these 3 spp. appear closely related, mainly by features such as: similar colour pattern of antennae, femora and caudal lamellae; mandibular formula; size of ligula; one palpal seta; shape of male and female gonapophyses, and the presence of claviform setae on abdominal stemite 8 and gonapophyses.