fwd black form E. Tiger Swallowtail

[Frank Mantlik]

I rec'd this e-mail Sunday 8/5 11:25am from Charlie
Barnard of Stratford <chasbarnard at aol.com):
Frank,
There was a female black form of Eastern Tiger
Swallowtail feeding in the garden this morning. It was
next to a more typical yellow Eastern Tiger, but was
really black on top and the tiger pattern could barely
be seen below. Maybe these are fairly common  here,
but it is the first one I can remember seeing.  Or
maybe I have just not been paying attention. Have you
ever seen one around here?

I replied that I don't recall ever having seen this
form.  How common is it in CT?
Frank Mantlik
Stratford