Identificaciones de cheloderus

These observations show five adult R. limbata, and are an extension of the earlier observations (https://inaturalist-open-data.s3.amazonaws.com/photos/251439703/large.jpg), in which I showed the foam, feeding chambers of this fly that were placed on the stems of Baccharis linearis. Those first 10 observations showed the foam chambers as they existed on the branches of one of these Baccharis bushes, along with pictures of a pupal fly that was in one of the chambers that I dissected.
As mentioned in the Notes section of that observation, I wanted to try to raise the larvae/pupae to metamorphosis as adults. In early January, 2023, I cut off the stems each of eight of these chambers (e.g., picture 11). I stood each of the branches upright in a tray with soil from the ground below the bush. I enclosed the tray inside of a large plastic bag. Occasionally, I sprayed the foam chambers with a fine mist of water, but kept the bag and tray pretty dry. The tray was on an open shelf in my apartment, away from direct sunlight. Six flies emerged from the eight foam chambers over a three-day period (15-17 February 2023). Frías (2008) wrote that this species is bivoltine (two reproductive periods/year) in Chile. If the flies in Argentina are also bivoltine, then these February flies probably represent the completion of the first breeding.
Of interest to me is that pictures of adult Rachiptera are rare compared with pictures of the foam chambers – of 14 Argentina observations only one is of an adult (https://inaturalist-open-data.s3.amazonaws.com/photos/175289665/medium.jpeg), and there is only one observation of an adult among 108 Chilean observations (https://inaturalist-open-data.s3.amazonaws.com/photos/298465734/large.jpeg. Notably, these two pictures show adults that differ greatly. The Chilean animal is yellowish with a transparent border along the posterior edge of the wings, while the (coastal Río Negro Province) animal is dark brown, with mottled coloration. And, the coloration of the wings is complete, without a posterior, transparent edge. The animals in my photographs are fairly similar to the Santiago, Chile specimen – yellowish and a transparent hind wing. This suggests to me that this coastal Río Negro animal is a different species of Rachiptera than the Chilean (and the Bariloche) R. limbata.