We report on four new transiting hot Jupiters discovered by the WASP-South survey .
WASP-178b transits a V = 9.9 , A1V star with T _ { eff } = 9350 \pm 150 K , the second-hottest transit host known .
It has a highly bloated radius of 1.81 \pm 0.09 R _ { Jup } , in line with the known correlation between high irradiation and large size .
With an estimated temperature of 2470 \pm 60 K , the planet is one of the best targets for studying ultra-hot Jupiters that is visible from the Southern hemisphere .
The three host stars WASP-184 , WASP-185 and WASP-192 are all post-main-sequence G0 stars of ages 4–8 Gyr .
The larger stellar radii ( 1.3–1.7 M _ { \odot } ) mean that the transits are relatively shallow ( 0.7–0.9 % ) even though the planets have moderately inflated radii of 1.2–1.3 R _ { Jup } .
WASP-185b has an eccentric orbit ( e = 0.24 ) and a relatively long orbital period of 9.4 d. A star that is 4.6 arcsec from WASP-185 and 4.4 mag fainter might be physically associated .