With butterflies, it doesn't matter much if you set them in their wings-flat resting position, as you can still see all of both pairs of wings, but with other l

With butterflies, it doesn't matter much if you set them in their wings-flat resting position, as you can still see all of both pairs of wings, but with other lepidoptera it definitely does make a difference. With few exceptions, when moths are resting, their hind wings are hidden, but setting them in the traditional way allows both wings to be seen. So I suppose for consistency, butterflies are set the same way that moths (i.e. all other lepidoptera) are. Incidentally, with a bit of practice you can sneak up to resting or feeding butterflies and photograph them close-up (e.g. with a smartphone), provided you don't make sudden movements. So now you can have proof of sighting and a permanent visual record without the need to kill them.