Charles, you really don't furnish enough information, eg., ages (other than Ethel), birthplaces, possible siblings and so forth. "McCullugh" is a fairly common surname and both William and Ethel are common given names. So one really needs more to go on than what you have furnished. You don't specify what records, other than the 1930 census,that you have sought (marriage, birth, death, other census records, etc.). Maybe some kind soul will do all the searching for you without more data but that's asking a lot on your part.