Lacewings

[Kayakasaurus]

http://m.phys.org/news/2016-02-paleobotanists-jurassic-butterflies.html

I wasn't going to post this doodle I did, but then I saw this article which increases the probability of this event occurring . The Article seems to say butterflies evolved twice, I'm just going to call them butterflies, they qualify in my book  .

[SBell]

It's not a matter of butterflies evolving twice--it's more that what we consider 'butterfly morphology' evloved (at least) twice among insects, through convergent evolution, since lacewings and butterflies are not directly related (not quite sure how closely realted they are--not big on insect taxonomy!).

But yes, in principle, a young sauropod might have played with a butterfly-like bug at some point. Just hope its neck didn't do that snake thing!