EOS Token (ERC-20) holders are reminded to make sure that they have registered their EOS Ethereum address(es) so that they're linked to the Mainnet map prior to June 2, 2018, at 21:59:59 UTC*. Registration allows addresses and associated balances to be identified after the release of the mainnet tokens. This process must be completed in order to have access to your mainnet tokens. Please review the article below on how to register.
https://support.decentral.ca/hc/en-us/articles/360001776114-How-to-register-the-EOS-tokens-held-in-Jaxx
Please keep in mind that your Mainnet tokens will not be stored inside Jaxx. However, Block.One will be providing your EOS mainnet wallet that you will only be able to access with your EOS private key. Also, note that all EOS ERC-20 tokens will be frozen and unmoveable from your Jaxx wallets after June 2nd, 2018.