under virtualbox, you need to "pass the USB devices through" from the host side to the guest side
click on the little USB plug icon at the bottom right of your virtualbox screen and select the "JeVois Inc JeVois-A33 Smart Camera"
If you then type "dmesg" in a terminal, you should see JeVois (see http://jevois.org/doc/USBserialLinux.html
I just tried it, and JeVois indeed apprears in the logs, but like you I cannot access /dev/ttyACM0 either through jevois-usbsd or through "screen", even though I am able to capture video from JeVois just fine using guvcview in the virtualbox. We need to do more research on this as it seems maybe VirtualBox has a bug with passing composite devices to the guest (JeVois is a combo of camera+USB drive+serial)
In the meantime, if you just want to program in python, you do not need virtualbox, so you can connect jevois to, e.g., a native Mac directly as done here: http://jevois.org/tutorials/UserUSBSD.html