I have a question from your tutorial. "The life of lepidopteras," is classed in science: 595.78. When we add a geographical number (such as 774 for Michigan) to denote "the life of lepidopteras in Michigan," I do not know how to add this geographical number.

One basic feature in the Dewey Decimal Classification is the list of standard subdivisions found in Table 1. Notation from this Table may be added to any schedule number unless there are instructions to the contrary. The most frequently used standard subdivision by far is --09, Historical, geographic, persons treatment.

Notation --091 is used for treatment by areas, regions, places in general (that is, treatment not limited by specific continent), and --093-099 is used for treatment by specific continents, countries, localities. All subdivisions in standard subdivision --09 are taken directly from (or are found in) Table 2, including --092, our biography number. Thus to designate Lepidoptera in Michigan, you must first add --09 to the Lepidoptera number, then add the Michigan number to 595.7809 in order to build 595.7809774.

Last revised: 30 December 2003