Cabbage butterfly and Small white

Cabbage butterfly noun - White butterfly whose larvae (cabbageworms) feed on cabbage.

Small white and cabbage butterfly are semantically related. In some cases you can replace phrase "Small white" with "Cabbage butterfly", this phrases are similar.

Small white noun - Small widely distributed form.

Cabbage butterfly and small white are semantically related. You can use "Cabbage butterfly" instead a noun phrase "Small white".