The known mature larvae of andrenid genera Spinoliella, Callonychium, and Arhysosage are described and compared with one another and with those of other Calliopsini. On the basis of both larval and adult anatomy, these three genera represent a distinctive clade, the “Spinoliella clade.” The larvae are characterized by conspicuously enlarged and oddly shaped, paired dorsal tubercles on the pro- and mesothorax, while the paired dorsal tubercles of most other body segments are erect, elongate, and slender. All dorsal tubercles bear fine setae. The larvae were collected on field trips to South America over a 35 year period. Associated field notes are reported, treating information on nesting ecology, nest structure and dimensions, provisions, larval behavior, associated cleptoparasites, and mating behavior. Also presented is a preliminary taxonomic key to the genera of Calliopsini based on mature larvae.