D. scorpioides and pulchella (not sure about the hybrid with nitidula)are a little later than most. They require more of a southern exposure, thus more light. Gemmae production is also tied into a drop in temps.

So, maybe a fan + a bucket of ice or something to lower the ambient temperatures in the room?

Or just turn off the lamp. That will lower the temps by a bit.

How about ever so slightly opening the window?

My worry is that they're in my ground floor apartment window, which I am not in for 12-13 hours a day. Kinda hesitant to unlock a window for that long.

I also have the D. pulchella x nitidula hybrid, but, it has started making gammae. I have it in an unheated terrarium that gets no natural light, but rather has only two 100W equivalent compact flouresent bulbs. I did increase the photo-period from 12 to 14 hours of light per "day," and it started gammae maybe two months later. Also, my room lacks heat, and so the temps in here can get a tad bit on the cold side, which also could have triggered the production.
How have you cared for them this past year? I wouldnt be surprised if they where treated sub-optimum, they would save the energy and not produce gammae....but then again, my conditions are far from optimum.

Bought them from California Carnivores, left them in their little square plastic pots for quite some time. I had 4 pots in one big saucer. They were slowly dying, not making dew, etc etc.

About 3-4 months ago I lifted them wholesale, the top layer of media and all, out of the pot and placed them gently into a big 7" pot. I put 2 butterworts (1 is dead and gone) and my single D. Scorp. as well as the patch of D. p x n all in there, with hopes to fill it with Gemmae this year... The media at the bottom of those 4" pots was stinking to high heaven, I tossed it out.

At the same time I changed my watering habits to frequent small waterings rather than filling up the 4" tall saucer each time I saw it was mostly empty. They have sprung to life since then, but still no Gemmae.

They are in a windowsill in my apartment, Western Facing I believe. They start getting natural light at approximately 1-2PM every day, until 6-7PM. At approximately 6AM I turn on a small 60W Glow Light in a desk lamp that is about 6 inches over their heads, and turn that off around 7-8PM when I get home.

The plan is to eventually have them on a shelf with CF bulbs over them, but I don't know what type of bulbs to get for that kinda thing yet, and still need to get a shelf system for them. There's a thread on that other forum about wire-based shelves being used for that, with each shelf having a row of plants on it and a light hanging underneath.