One of the most common butterflies found around here is the cloudless or common sulfur. This is a medium sized yellow or white butterfly.
There are actually two species found around here that look almost identical from the side. The other one is the orange sulfur. The difference in the two is that the upper surface of the orange sulfur is orange, and the upper surface of the common sulfur is yellow. The orange sulfur is also slightly larger than the common sulfur.
Both are native to the United States, and both have apparently greatly increased ranges by feeding on the non-native alfalfa and clovers. Apparently they hybridize readily now, making butterflies that are already difficult to differentiate even more difficult.
Common and orange sulfurs are among the first butterflies to be seen in the spring and are common all year long. They are typically among the last butterflies to be seen flying in the fall.
I find them a little more difficult to sneak up on to photograph than most butterflies, and I think part of that might be due to the fact that they nectar most often on flowers which aren't particularly big, such as small asters, alfalfa flowers, etc., and which probably don't have a lot of nectar. Therefore, they don't stay on one flower too long, and usually not long enough for me to sneak up on them. I did have some success with puddling sulfurs, however.
The flower this particular butterfly is on is purple cone flower which probably has a lot of nectar and is a very good butterfly flower.
This is one of my early butterfly pictures, and one of my favorites. This picture showed the large green eye and some of the details of the hairs that I had not realized were there. I guess I didn't realize that butterflies had much hair but they are covered with it.