Butterflies

I was recently home over the weekend and noticed quite a few butterflies. Now, I don't really know much about their classification other than I saw what appeared to be quite a few monarchs. This left me pondering, and I realized that there is milkweed in our yard, which is the sole food of monarch larvae. I have not however noticed any butterflies in Philadelphia. This could be because of the different habitat between my yard and Fairmount Park, or perhaps they just need more milkweed planted. I think I will continue observing and maybe planting!!