Ed Yong in Not Exactly Rocket Science:
There’s a group of fossils insects that look really quite a lot like butterflies. They had broad wings with scales and pigmented eyespots. Their mouthparts were long probing straws. They likely fed from plants and pollinated them in return. They’re as butterfly-esque as it’s possible to be.
Except these creatures were flying around between 40 and 85 million years before the first butterflies existed.
They were kalligrammatid lacewings, and they were doing butterflies before butterflies even were a thing. Their resemblance is a coincidence, an extraordinary example of convergent evolution, the process two groups turn up to life’s party accidentally wearing the same outfits.
The kalligrammatids appeared around 165 million years ago, during the Jurassic period, and died out 45 million years later. During their reign, they were among the largest and most conspicuous insects around. Time has since been unkind to them: many became fossilised but most have been badly preserved. Scientists have commented on their similarities to butterflies for more than a century, but no one has been able to thoroughly study their anatomy—that is, until Conrad Labandeira and Dong Ren from Capital Normal University in Beijing got their hands on some beautifully preserved specimens from northeastern China.
More here.