Having put it off for a couple of posts now, these are my NPC stat lines, formatted as (hit dice), (armor class), (normal attacks), (special abilities):
Note: all insects can use scent and vibrations as substitutes for sight, no change in stats if infected
Swarms: HD 1, AC 9, 2 damage/round autohit to all within swarm (1d2-1 damage if warded off), SP: takes half damage from non-area attacks
Workers: HD 1, AC 6, bite for 1d4 damage
Soldiers: HD 2+2, AC 5, bite for 1d6 damage or 15 ft.-long cone of adhesive spray (save vs. breath or trapped [as Web] for 2d4 rounds)
King/Queen: HD 2, AC 6, bite for 1d4 damage, SP: can command nearby workers/soldiers
Sundew: HD 4, AC 8, constrict for 1d6 digesting+2d6 burning damage + grapple, SP: grappled targets are auto-hit for doubled digesting damage, emits 30 ft.-radius pheromone cloud (save vs. death or be charmed for 1d4 rounds to approach and allow grappling), generally stationary
Faerie: HD 6+2, AC 3, claw for 1d6 damage + toxin (save vs. death or suffer -2 to all d20 rolls for 1 turn, non-cumulative) or toxic kiss (save vs. stone or be paralyzed for 2d6 turns), SP: can turn invisible at will and stay invisible while attacking, can see in darkness, immune to poison and disease, cannot be surprised
Ant, scorpion, and termite swarms are like reality.
Normal workers and soldiers look like 3-4 ft. tall termites. Hive mind like real termites. They're open to food bribes and aren't aggressive unless put on alert or unless invaders threaten their food/safety.
Infected workers and soldiers have mossy clumps clinging to exoskeleton joints. They move like herky-jerky puppets. They're controlled telepathically by the hanging moss in 42a and serve it slavishly. They seek to bring invaders into its service, ideally by exposing them to spores so it can manipulate them through communication but resorting to capture and implanting if necessary.
The hanging moss is an alien thing from the dark depths, an outgrowth of the progenitor moss. It has a cunning intelligence that wants to spread, but it knows nothing of the ways of surface peoples (yet).
The sundew is a rosette (like Drosera capensis) with a 4 ft.-diameter core and 18 ft.-long tentacled leaves that radiate heat. The tentacle mucus is acidic and glows with blacklight (equal to a torch; scorpion chitin glows in blacklight). It's a mindless plant. It can ride air currents from 26 to 17 but needs a day to return afterwards.
The faerie has a chitin-armored humanoid torso atop six scorpion legs, with a narwhal tusk protruding from his lower jaw and solid black eyes. He wants the hive caller and hates termites. He can command the sundew and scorpions. Mostly charming but with a creepiness that comes out in prolonged conversation, he can impregnate humanoids with scorpions. He wears the glove of bodily storage.
As an aside, let me say that coming up with mechanics for "glove/gauntlet of inner/self transformation" proved to be more challenging than I'd expected, but I like what I came up with in the end. The glove of bodily storage looks like a simple black leather glove. The wearer can use it to transport any single thing entirely within their body to an extradimensional space or to retrieve the thing, which reappears in the same part of the wearer's body. Removing the glove causes the stored thing to reappear in the former wearer's hand immediately. Currently, it stores a key to the faerie's realm (taken from his mouth). I can't trace the exact path of thoughts that lead me to this final product, but I have a fondness for these odd items that get an initial "why would you want that?"-reaction, following by immediate brainstorming of why indeed.
I have no exact mechanics for the hive caller yet, but that can wait for the final key.
I had put down dice formulae for keyed encounter quantities in the previous post, but those were rough guidelines for myself; I intend to fill in actual numbers for the final key because I see nothing to be gained by rolling for those in play. In order to gauge the combat potential of the monsters, I like using Delta's idea of equivalent Hit Dice (EHD), since I can make a quick estimate at that and check it against something similar in his monster database to make sure I'm not wildly off. Looking at the total EHD (tEHD) in comparison to the party's total HD isn't perfect, but it's good enough as a quick tool to eyeball if direct combat would be a reasonable approach. I like for the majority of encounters to have a tEHD somewhat below the party's total HD so that the likely attrition for most combats isn't going to end the expedition immediately, a significant minority to be about equal so that preparations/tactics/etc. play a key role, and then a handful of encounters to have notably higher tEHD to encourage non-combat approaches. For this dungeon, I'd translate those guidelines into about 60% encounters under 6 tEHD, about 30% in the range of 6-9 tEHD, and the remainder can be whatever they are.
The stat lines for workers and soldiers are fairly similar to Delta's goblins and gnolls, respectively, coming in at 1 and 2 EHD, respectively, which sounds good for making up the bulk of the encounters. There isn't really a good equivalent in OD&D for swarms (for which I take direction from Moldvay Basic), but the numbers look close enough to what workers can do that I'd expect them to be 1 EHD as well. The king/queen are somewhere in between, but that doesn't matter much because they're only encountered in a room with enough other termites that I'm sure it'll be on the high end of the tEHD ranges. The sundew ended up being similar to a medusa, which caught me off guard with how high its EHD is, probably due to its area of instant death via petrifying appearance; the sundew's pheromone cloud isn't quite as bad since it just disables instead of killing outright, but it's nasty enough (together with the sundew doing 3d6 or 4d6 damage per attack) to probably end up around 10 or 11 EHD. That should be quite difficult to fight directly, but it has clear enough issues with range and mobility that I think skilled players can deal with it in practice. The faerie is even more wonky, so I tried looking at all of the monsters with either invisibility or paralysis for trends; neither seemed to be worth more than +1 EHD without synergy from incredible AC or multiple attacks, respectively, so I'll gauge him as about 7 or 8 EHD, which means fighting him directly can be a viable option (especially if he can be isolated from the sundew).
For a random encounter table, I decided to go with a single table that alters the dice formula depending on the dungeon level; stepped tables are well and good in theory, but I prefer sticking with just a single roll when I can. Thus, I ended up with:
Roll 1d2 for lower level 2, 1d4 on lower level 1, 1d4+1 on ground level, 1d4+2 on upper level 1, 1d2+4 for upper level 2
1 - 2d4+1 infected workers foraging to feed the king/queen
2 - 1d6 10-ft. swarms of termites or ants hunting
3 - 1d6 workers wandering to feed/groom soldiers or tend to fungal gardens
4 - 2d6 workers leaving to forage or returning from foraging
5 - 1d6+1 10-ft. swarms of scorpions hunting
6 - Faerie (invisible)
On a related note, I'm a proponent of James Young's non-binary approach to encounter checks, with AD&D times for light durations:
Roll 1d6 per turn
1 - Random encounter
2-4 - Evidence of creatures (e.g. traces of moss, fresh droppings, dead remains, cleared space that mundane swarms haven't refilled yet, voice in the distance) or environmental effects (e.g. smells on air currents, incidental clash between termite and ant swarms, sounds of weather change, odd reflections of light)
5 - Candles and torches burn out
6 - Candles and torches burn out, lamps and lanterns burn half of fuel
As Paul did with his design series, I'm going to save filling in all of the remaining rooms for the final key instead of going through each one here. What I think could be useful to mention, though, is the general distribution of room types. The expected rates for different room types depends on which system is being followed, but for a 44-room dungeon, rounding to the nearest integer gives:
Per OD&D (Vol 3 pg. 7): 29 empty, 15 monsters, 12 total rooms with treasure
Per B/X (pg. B52): 15 empty, 15 monsters, 14 trap/trick/special, 12 total rooms with treasure
Per AD&D (DMG pg. 171 Table V. F): 29 empty, 11 monsters, 4 trap/trick/special, 9 total rooms with treasure
Personally, I think the AD&D rates are a fair fit for this dungeon; the low treasure makes sense given that it's mostly insects that can't think about much more than survival (and the more intelligent beings are recent arrivals), and monsters should be more common than traps/tricks/special for much the same reason. I'm not going to stick to those numbers firmly (I've almost doubled the AD&D trap/trick/special total already, depending on how I count certain rooms), but it's good to see that having a 1:5 or 1:7 ratio of monsters:empty for the rest of the dungeon, with a 1-in-20 chance for some random treasure, should come out to a reasonable situation. I'll use more random tables for inspiration on dressing up the empty rooms (Tome of Adventure Design book 3 part 2 or OSRIC chapter 4 are useful resources, though they'll need adapting for a termite nest), but I'll definitely want to include some people encased in hardened adhesive spray as an excuse for replacing dead PCs. Not a critical consideration, perhaps, but I think it rarely hurts to have some idea of how to introduce new PCs, especially if the dungeon doesn't really support having captives.
Having set those guides for myself, I'm pretty much set to go ahead with random stocking for what's left (rolling on the random encounter table to pick monsters, if necessary). I'll take care of that, put together the final map and key document, and come back with one last post to call out any notable developments and give my overall thoughts on this whole exercise.