Thank you Steve, for spending time on this one, and on some of my others. Looking at what I have in my files, I better stick with genus for those "deltoids" for a while. The size difference between sobrialis and adspergillus actually is quite small and perhaps within the error margin of measurements on fidgety live moths. As to the listed wingspans of pinned moths, they may not be all that reliable either as I have discussed on the Moth Forum.

See comments by J. D. Roberts on one of my own images here. He mentions wing shape. Compare yours and mine to Mark's DNA tested example here. Looking at pinned and BOLD images, this wing shape, though not consistent within adspergillus does not seem to be found in sobrialis. That said, I'll leave a comment on my image for Jason and ask him to check yours.

But maybe I should have placed it at the genus level. I place images to species as tentative IDs if I think think there is clear evidence supporting the ID and eliminates similar species which in this case there is. However the evidence may be bad. I'll try to find more updated descriptions and get more info from experts.

My wing"spread" measurements are from wingtip to wingtip of moths when wings are not horizontally extended. Estimated wing"span" in this case would come out to be about 28mm.
Thanks for your help with these moths!

Smith's 1895 paper on Deltoid Moths here includes species descriptions and a key to Renia in which he mentions that adspergillus, formerly the now lumped species larvalis and restrictalis, and sobrialis are inseparable except by size. According to his measurements, this would be adspergillus. R. sobrialis is a little smaller. I don't know where the size numbers came from for the Vargo images at MPG for adspergillus but I suspect they are incorrect. Smith notes that Grote's measurements were different than his and concludes they were in error. This along with the rest of his explanation lead me to believe that Smith was thourogh.

It therefore appears that all of the identifications in these two species at BugGuide, including my own, are not reliable except for those specimens which were measured, dissected, or DNA tested. I'll dig around and see if there is more current information.