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Transit surveys employing small telescopes have revealed a population of ultra-hot gas giant planets (T_eff > 2000 K comma R_p > R_Jup) orbiting early-type stars comma worlds unlike anything in our solar system. Many of these planets orbit hot host stars (A-type) with very short periods (P_orb < 5 days) comma experiencing large radiative heating rates. These ultra-hot planets are the most far-ultraviolet (FUV)-irradiated systems known. However comma their extreme-ultraviolet (EUV) irradiation comma which drives mass loss from traditional hot Jupiters comma is likely quite low. We propose an FUV transit spectroscopy experiment to study four planets straddling the ''EUV divide.. to quantify the transition from EUV-driven to FUV-driven escape. We will use these data to measure the dependence of atmospheric ionization and mass loss rate on the relative strengths of the stellar FUV and EUV radiation fields. A-stars emit strong photospheric flux at FUV wavelengths comma providing a backlight against which a myriad of outflowing species can be observed. Our FUV spectroscopic program will measure transit depths in never-before-detected low-ionization comma neutral comma and molecular species believed to be rapidly escaping from the atmosphere of these planets (e.g. comma S I comma Si II comma C I comma N I comma Al II comma and possibly CO and He II). These observations will provide mass loss and atmospheric ionization measurements of planets orbiting A-type stars to test the importance of the FUV-EUV radiation environment and characterize atmospheric escape in its most extreme forms.