Going into the plains too early makes deathsquitos terrifying. They're pretty trivial, however, when you get there following the intended biome/equipment/boss progression.

Once you have max-lv silver armour (as you should at that point) they become a minor inconvenience, esp if you're using a shield (also highly recommended).

Deathsquitos only have 10HP, so I always carry a stack of cheap wood arrows just for killing them. 90% of the time I'll snipe them from a good distance, but up close a good parry-smack is even easier thb. The AI is slow and predictable, attacking only at long intervals.