It's the scarecrow or ghost of the ordinary station-fly.

Could you have imagined the station-fly could have a ghost ?" "No," retorted Mabel, "being so scarecrowy and ghost-like already.
Please, driver, take Captain Bertram's things up to the house.

He heard you speak, Loftie.

These Northbury people are as touchy as if they were somebodies.

Oh, Loftus, you will be disappointed.