The beads in the center of each wing, beneath the tatting, are clear iridescent beads. I love the way they pick up the color of nearby objects.
Someone asked me about bead sizes. I keep a collection of interesting beads, many of them were once part of necklaces. In fact, I used four different necklaces for seven different sizes of beads for this butterfly. I also used seed beads from a bag of inexpensive glass seed beads of mixed colors that I once picked up at Hobby Lobby. I've used the blue, purple, and pink ones from that assortment. The largest bead is the one in the body of the butterfly. It is 1.5 cm in length. I sewed it in vertically rather than horizontally as it is oblong. If you make the butterfly following Angela's instructions exactly, you will not use as many different sizes and colors of beads.