Yeah, aphids. They'll do some damage in a hurry. Out here, the ants bring them in. I remember one day, watching a trail of little ants, each of them with an aphid in its jaws. I thought they had nabbed 'em and were taking them back to their nest somewhere. But no. They all crawled up a Rhynco to the top of the spike, and set the things down, right where the buds were appearing. I couldn't believe it. It was like they were taking care of them, putting them right where the best feeding spot was. (I must have been bored that day, looking at ants...)
I hate using insecticide but, finally, it's got to be done. We don't spray as rampantly as some growers because, in my opinion anyway, the orchids seem less --perky?-- after an application. But to apply it properly and make sure you get all the eggs and larvae, you need to spray three times, waiting about 8 - 10 days in between. That way you'll be sure to kill anything on its way out of the egg. We do that about every four-five months or so and have found that it's often enough to keep the insects off of our plants.
Good you did the other plants too. Those bugs probably came in from that home improvement lot you purchased a little while ago...
(Ok, probably not... I'm just just kidding... I read what Brutal said about pests on here somewhere and here you are, saying you've got some a few days after lol! )
Anyways... No big worries; bugs happen. Glad you caught 'em!