Alright, let's do a run down on the Swarmlord.
Role and BaB
You mention it's supposed to take a similar role to the Sorcerer or Wizard with Wildshape and touch attacks to bring it into melee range. And I see it's supposed to be thematically similar to the Druid, so I can see the rational for a medium BaB progression.
But the Paizo team specifically nerfed Wildshape as a combat option and made it quite known that they only saw it for scouting and utility, nothing more. Touch attacks also generally land because most creatures have a much lower touch ac compared to their normal ac.
So, do you really need a medium BaB progression on this guy?
I notice that your usable swarm's CR as you level reflects the spell level a full caster would have at the same time. The issue with that is that as you level, your Swarms are less and less a threat for what you'd be using them against. Take the Tick Swarm for example; CR 17+ creatures wouldn't be threatened by a CR 9 creature. The swarm traits take care of this in some ways but when your enemies start being casters or dragons or powerful outsiders, those traits become like Damage Reduction/Magic.
Isn't this as a whole a little limited and/or superfluous? Why not just make the swarms able to move and act on their own and just have it be a swift action or something similar to direct the swarm as a whole?
I have to ask; why a hellwasp? This class doesn't have any connections to the Hells so it honestly feels tacked on. Why not just make it so the Swarmlord can gain any appropriate vermin as a familiar and have the Hellwasp as one of the options?
What about swarms of Tiny creatures? Otherwise this ability looks fine but you may be getting it too early. The DR is very limited, but those immunities can be useful. It just makes the class really front loaded for level 1 and attractive as a dip. Also, I think you mean sickened, not sickness.
Why poison use? The Swarmlord can create swarms with poison special attacks and the class is centered around offensive usage of swarms. Just something else that feels kind of tacked on since Poison use is generally a stealth/assassin class thing.
Does this apply to magical or supernatural poisons as well?
What exactly is a "large swarm"?
Does this apply to magical or supernatural diseases as well.
The first part of this is really niche and the second part is definitely too little too late. Flat immunity to Mind-affecting effects would be more suitable honestly.
This...is a really weak capstone ability to be honest. It doesn't really entice someone to take all 20 levels in this class.
Oh and I should have said this earlier (with Bel's entry), but I just want to be clear that I don't mean to come off as mean or condescending or picking on the entries I look over. I'm just be thorough in my critiques of the entries so they can be polished and be the best that they can be.
@Ladybug: I'll give your class a run down when you've finished the Crown Worm and Worm-Eaten template.