Okay, I am musing about tweaking the
Giant Tropical Damselfly to STR 20 (+5), DEX 17 (+3) so it has the same DEX +6 saving throw as its smaller cousins with their DEX +6.
It just seems odd for a beast that must weigh as much as a rhinoceros to be better at aerial dodging and evading than one the size of a man.
The Armor Class can remain at 15. Presumably it has 2 points of natural armour instead of one.
Similarly, I'm tempted to downscale the
Giant Damselfly to STR 11 (+0), CON 10 (+0),
Hit Points 13 (3d8) and
Armor Class 14 and make it Challenge 1/2 (100 XP) with (escape 10) for its grapple.
An average sized Damselfly is a lot less powerful than an average sized Dragonfly, although it's still an efficient aerial predator. I'm imagining the Giant Damselflies mainly hunt on the wing and specialize in Tiny flying prey items (e.g. Bats, birds (including hawks, owls and ravens), flying snakes, stirges and giant mosquitos). That means they don't post much of a danger to humanoids such as adventurers, while Giant Dragonflies will attack hefty prey of Small size or larger even if they're on the ground or too heavy to fly with.
The original 1E AD&D version of this monster describes Giant Dragonflies says they "giant dragonflies are dangerous predators known to hunt humans. Because of their fearless nature and voracious appetites, these huge insects hunt not only all other sorts of similar creatures but prey on any warm-blooded creature as well." The 2E AD&D version has "the giant variety is a dangerous predator that attacks any creature its size or smaller. … When attacking creatures of tiny or small size, a dragonfly scoops its victim into its leg basket and devours it in midair. Once caught in the basket, the creature automatically suffers bite damage each round until completely devoured. When attacking larger creatures, a dragonfly darts in to bite with its mandibles."
So I've interpreted that as capping the Multiattack and Legs attacks of the
Giant Dragonfly to Small size, so it can't grab anything bigger.
For the Giant Damselfly, I've gone for a cap of Small on the Legs but Tiny on the Multiattack that represents the "basket scoop", so it can easily catch Tiny flying creatures but would be reluctant to attack Small flying prey, since it's have to grapple them with its legs on the first turn and bite them on its second turn, which gives them an opportunity to counterattack.
If we extend the above to the Tropical Giant Damselfly, that'd give them a cap of Large on the Legs and Medium on the Multiattack. As mentioned in a previous post, this isn't as dangerous since it has a 10 foot reach with its Legs, so if the prey only has a 5 foot reach with its attacks the insect can grab them with its first attack and it holds them too far away for the prey to counterattack until it draws them in close for a bite attack on its second turn.
Do you have any comments or objections to that?
Boy, that's far wordier than I originally planned!