The Syrmatia Dorilas has a very unique butterfly shape, with unusually long hindwings. It is found in the Amazon rainforest.
The free chart for this butterfly can be printed from: http://crochet.about.com/nbpatt3.htm ... it's a chart that I designed in the year 1997.
In the example above, I crocheted the square entirely in the background color in single crochet (you could do it in afghan stitch instead) and then, with yarn, using a large-eye needle, I cross-stitched the butterfly design on, following the chart (reading the chart as one square on the chart = one single crochet stitch).
When crocheted with worsted weight yarn and a US size G hook, the finished square is about 10 inches wide. You might prefer to use other materials for a smaller or larger square.
The chart is 40 squares wide so, to make a background the same size as the chart, the starting chain is 40 chains for afghan stitch or 41 chains for single crochet.
You could crochet from the chart with color changes or crochet a plain background and then cross-stitch the butterfly on the finished background square.
Butterfly design copyright (c) 1997 by Sandi Marshall, licensed to About.com, Inc. Pattern is free for your own personal (not for profit) use only. Per copyright law, do not redistribute in any form. You are welcome to give the link to others who want the chart.