In the European Parliament, parties operate as groups of national parties, see e.g. current europarties. They don't take members and don't operate in countries where they don't have any membership party. They're rather organisational vehicles for parliamentary work than true parties.
Are there any truly EU-level political parties? By truly EU-level, I mean that they operate on EU-level in a way analogous to how traditional parties operate on a national level. For example, aiming to operate everywhere in the EU, allowing membership from anyone in the EU, and encouraging members anywhere in the EU to start local sections (at local, regional, or national sections).
The list linked above only includes parties currently represented in the European Parliament. I know that no party according to my criteria currently has any representation, but are there any that are presently without representation?