We need to connect with IP address to the emulator, so look for the IP address of the running emulator (it's shown in the emulator title bar) and use something like:
adb connect 192.168.56.102:5555
Afterward adb
works normally. You may also find out the IP address of a running emulator by starting "Genymotion Shell" and typing 'devices list'
I also find out that occasionally I have to do the above when the emulator is running for a longer time and somehow ADB disconnects from it.
Greg