Yes, all self ballasted mercury lamps (those that run directly on mains) are blended because there needs to be a filament to act as a ballast. The only exception are the self-ballasted metal halide which have a small electronic ballast built in. However, those are not what you're after...
There is no escaping a ballast : the arc tube will destroy itself in a fraction of a second if there is no ballast. Either the ballast is a filament such as SBMV or a standard ballast separate from the lamp.
I believe most people who collect insects at night prefer a standard clear mercury vapour lamp, which of course requires a separate ballast.
Okay thanks. I'll probably buy some of those then though I'm still looking for other models, my favorite being the fluomeric 750w though those are very rare. Also a lot of insect collectors do use SBMV and not regular ballast.