Mosquitoes. Definitely!
I remember when I was a kid during WWII one of the servicemen's annuals had a poem in it about "Mike the Malaria Moskeeta".
The author's name is unknown, but he was from New South Wales, and his regimental number was NX116478.
In tropical regions, there’s “mozzies” in legions but none cause havoc completer than one little devil who’s not on the level, it’s Mike, the Malaria Mo-skeeter.
With no foe or ally is Mike ever pally, his aim is to be a world beater; for Tojo and Aussie’s the same to this mozzie, to Mike, the Malaria Mo-skeeter.
The world’s aviation has yet no creation. Like Mike in his striped single-seater, bad trouble is comin’ when you hear the hummin’ of Mike, the Malaria Mo-skeeter.
He sure is a glutton and he won’t eat mutton—no sir, nor is Mike a beef eater; for Mike likes consumin’ the blood of a human, does Mike, the Malaria Mo-skeeter.
So please heed my warning, at sundown or dawning, altho’ you may dwell in a heater; just keep yourself covered, lest you be discovered by Mike, the Malaria Mo-skeeter.
In time’s smallest fraction you’ll be put out of action if once he injects his saltpetre. The world’s greatest vermin is not Jap or German—it’s Mike, the Malaria Mo-skeeter.