Zegra Jungle Empress, also named Tegra for the first issue was a five issue series by Fox in 1948. Despite changing names, it looks like her hair color changed as well. I have been informed by a Fox expert that the first issue of Zegra/Tegra was an altered Rulah story. Apparently they whited out the giraffe pattern on her outfit and added the tiger stripes. In the text to the stories, the name Rulah was whited out and the name Tegra was added. See the last scan for yourself (thanks Dagar).  It appears as if it is typeset print with the name Tegra handwritten in(similar to Kohla). Rulah's pet panther Saber  also appears in this first book.  With further issues Tegra became Zegra and became blonde.