Bees produce the beeswax used in the construction of their combs from the four pair of wax glands located on the underside of the abdomen. These glands are most highly developed and active in bees 10-18 days old. The wax appears in small, irregular oval flakes or scales that project between the overlapped portions of the last four abdominal segments. Wax can be secreted only at relatively high temperatures and after a large intake of honey or nectar.  - John Skinner, University of Tennessee