It's either a sleepy orange or a little yellow. They're nearly identical, size being the only difference. I find that sleepy oranges are more common, so that's probably what
it is.

There are three sulphurs that use cassias/sennas here and probably where you are - cloudless sulphurs, sleepy oranges, and little yellows.

Sherry

Here are pictures of a Little Yellow cat & crysalid I brought in last month. The cat was only about 3/4" long before it pupated.
Little Yellow Cat
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Little Yellow Crysalid
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I have also brought in a couple of Cloudless Sulphur cats this past week off of some of the Partridge Pea(Chamaecrista fasciculata) plants I have growing & one was a yellow cat & the other green. I thought I had a different kind when I saw the yellow cat but it is because it had been eating the flowers of the Partridge Pea.
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I currently have several sennas in the same BF bed including Coffee Senna(Senna occidentalis), Candlestick Cassia(Senna alata), & Argentine Senna(Senna corymbosa) as well as the native Partridge Pea(Chamaecrista fasciculata).
I am putting a link to Dallas Lep Society for you...it has pictures of some of the cats & lots of info about our local BFs!(for some reason the link won't work but this is the site)
http://www.dallasbutterflies.com/
Lila

OBTW...I also had a Orange Barred Sulphur on my Candlestick trees in 2010 but the cats didn't look anything like your picture.

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I would think your's is a Sleepy Orange!