Do BL Lac Objects and FR I radiogalaxies inhabit the same galaxy
  environment?
  We investigate the environments of galaxies around BL Lac objects and FR I
radiogalaxies, the alleged parent populations of misaligned sources. We compare
the environment of a sample of 50 BL Lac objects at 0.1<z<0.33 with that of a
sample of 90 FR I galaxies at 0.1<z< 0.15. The galaxy environment is estimated
using the SDSS images in the i-band. We find that the galaxy excess density
within 0.5 Mpc around of FR I radiogalaxies is a factor ~ 2 larger than that
around BL Lacs. This implies a reconsideration of the parent population of BL
Lac objects.
