Found what looks to be six Anise Swallowtail larvae on my garden dill...

[Sylphenom1 at aol.com]

I live in Maryland (near Baltimore) and was recently alerted to the fact that
there had been a sharp decrease this season in the number of butterflies in
this area due to the weather. 

I've recently discovered what seem to be six, nice, fat Black Swallowtail
larvae hungrily devouring my dill...which I'm delighted to let them have (they
need it more than I do).  Should I leave them alone, or should I protect them?
I'm afraid, I haven't got much more in the way of dill left for them...and I
don't know where they'll go if they manage to finish it off...it seems that
every couple of days, a new one shows up!

If you've any advice for me on this subject, I would love to hear from you!
Thank you so much for taking the time to review this!  I do appreciate it!

Sincerely,
Johanna Lederman
Sylphenom1 at aol.com