BOZ
Creature Cataloguer
Shade said:I find it odd that the 2E stat block listed 'em as S (4' long), and then the text goes on to say they are 8-feet long. I agree with your decision to make 'em Large.
editing mistake.

Yeah, while I was setting up the stat block, I was even setting them up to be Small… until I read that line in the text and said, “yeah, that does make sense!”
Shade said:Poison: 1d4 Con/1d4 Con?
“10 hp” is a weird damage value. In any edition of D&D, it is uncommon enough to see damage as a non-variable number. Given the size and power of this creature, I’d say your idea should work.
Shade said:For ability scores, here are some comparable bug-like creatures:
Greater kruthik (MH) Str 25, Dex 20, Con 19, Int 4, Wis 13, Cha 10
Ankheg: Str 21, Dex 10, Con 17, Int 1, Wis 13, Cha 6
Chilblain (FB): Str 28, Dex 17, Con 24, Int 5, Wis 14, Cha 19
Knell Beetle (MM3): Str 26, Dex 10, Con 23, Int --, Wis 11, Cha 11
Giant Ant Queen: Str 16, Dex 9, Con 13, Int —, Wis 13, Cha 11
Giant Stag Beetle: Str 23, Dex 10, Con 17, Int —, Wis 10, Cha 9
Giant Praying Mantis: Str 19, Dex 8, Con 15, Int —, Wis 14, Cha 11
Based on that, I'd recommend the following ranges:
Str 23-26, Dex 10-17, Con 17-21, Int 6, Wis 13-14, Cha 10-11
they must not have a very high Wisdom if they can’t tell a mind flayer from another humanoid-shaped creature.

hmm, how about…
Str 24, Dex 15, Con 20, Int 6, Wis 13, Cha 11