Fundamental differences between the California Sister and the Arizona Sister  

(Adelpha californica vs. Adelpha eulalia)

Over the years, there have been several butterfly enthusiasts who have inquired about the differences between the Arizona Sister and the California Sister.  The purpose of this short article is to discuss as well as to illustrate their most basic, consistent differences. 

As shown on the images below,  the ventral hindwing of the California Sister (Adelpha californica,) has a lavendar background as opposed to the blue background of the ventral hindwing of the Arizona Sister (Adelpha eulalia.)   

Furthermore, if you look at the upper corner (adjacent to thorax) of the ventral hindwing, you'll see clearly that A. californica has two orange bars (one smaller than the other) and that A. eulalia only has one longer orange bar in the discal cell in the basal area.   

Also, if you take a look at the vhw cream-white bands of both taxa, the Arizona Sister clearly shows a continuous slim blue line on the outer edge of the band.  At the same time, if you look at the same area of the California Sister,  you will see that the same vhw lavender line is only intermittent.  These differences, having looked a long series of both taxa, appear to be diagnostic as opposed to being individual variation.

Todd L. Stout

2 bars on A. californica	1 bar on A. eulalia

Click here for a photo life history of Adelpha eulalia.

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