Floridobolus penneri produces five different burrow architectures, each with multiple possible modifications including the addition of chambers, branches, and spirals.
Open burrows are used as temporary shelters to permanent dwellings. Burrows are generally vertical (75-90 degrees) in orientation, but individual elements may also be horizontal (0-5 degrees) to oblique (15-50 degrees). Shafts and tunnels are circular in cross section (W/H ratio ~1.0) with relatively a consistent circumference along their length. Tunnels are straight to sinuous. Branching is uncommon but does occur in some vertical burrows. Chambers are two to three times larger than the connecting shaft or tunnel. Burrows were kept open while occupied and not backfilled, although fecal pellets were deposited at the ends of some tunnels.
Additional resources are available within the downloadable PDF and Excel files linked at the bottom of the page
Florida Scrub Millipede Burrow Data Spreadsheet (Microsoft Excel – Auto Download)