This is slightly different from both homing missile bots and a "basic" drone enemy. The idea is you have the mother bot that sends out its broodlings (whatever you'd like to call them) one by one, once every 10 seconds or so, to meet you coming its way. It can sense you from a pretty far distance away so it knows when to start doing this. The broodlings act as missiles in the sense that they hurt you on impact but they don't explode if they hit something else. They also have a limited rate of rotation so if you spot them in time, they're not very difficult to dodge. If this happens, they will keep going slowly turning around and if you got preoccupied, you might have forgotten about them when they surprise you from behind.
Because the mother itself is fairly vulnerable with no other attacks, it stops firing broodlings if you get too close because this would give you clues as to its exact location. For whatever reason, I picture it looking like