Industry is one of the most problematic census variables in terms of comparability. Each sample codes industry into the contemporary Census Bureau classification scheme, which changes considerably over time. The Census Bureau also dramatically reorganized its classification scheme in both 1910 and 1940. As a result of this complexity, IPUMS created the IND1950 variable to enhance comparability of industry data across years. However, IND1950 values for the 1880 census are inferred from the respondents’ reported occupation, because industry was not collected directly.
To see more detail of what each IND1950 category contains, you could try comparing the values of IND in 1940 with the IND1950 categories (see IND1950 crosswalk here). While this is unlikely to provide substantially greater detail, some of the original 1940 values were aggregated in the process of creating IND1950. You can also refer to the Occupation and Industry Variables documentation for additional information on the industry variables.
Hope this helps.