English: In species with enclosed pupae, workers consume pupal secretions directly from the cocoon. (1) Gently touching a glass slide to the surface of a Ponera pennsylvanica cocoon after 1 day in social isolation produces a droplet of pupal fluid on the underside of the slide (arrowhead). This illustrates that the pupal fluid readily crosses the silken fabric of the cocoon. (2) A Myrmecocystus mexicanus worker drinking dyed pupal fluid from a cocoon. The arrowhead indicates ingested blue dye visible through the translucent cuticle. The dark black spots at the bottom of the cocoons in (b—g) are the larval meconia, i.e., the metabolic waste products expelled by ant larvae as they enter pupation. The experiments and observations in (b—e, g) were repeated with at least n = 3 cocoons, yielding consistent results. Representative images are shown here.