Some kind of fly, gnit, gnat, tick or flea of some kind...the desert kind.
Under it all he went down in the grass of the slope, fighting with all his strength, but powerless as a gnat in a pond.
The one that causes the most irritation is smaller than the average English gnat.
Then he began to contemplate it, much as a philosopher contemplates a gnat's ear in the ample field of his microscope.
He walked round them the first time, but there was no sign of the gnat.
Miserable hypocrites, who swallow so large a camel and strain at so very small a gnat!
But this would be straining at a gnat, and swallowing a camel.
It is very absurd in these worthy defenders of the justice of God to strain at a gnat and swallow a camel.
To these must be added the Druid frigate, the sloop of war, and the gnat.
I have seen him watching him with angry and puzzled gaze as though he would satisfy himself why this gnat of a man worried him!
Old English gnætt "gnat, midge, mosquito," earlier gneat, used of various small, flying insects, from Proto-Germanic *gnattaz (cf. Low German gnatte, German Gnitze); perhaps literally "biting insect" and related to gnaw.
The gnatte is a litil fflye, and hatte culex..he soukeþ blood and haþ in his mouþ a pipe, as hit were a pricke..And is a-countid a-mong volatiles..and greueþ slepinge men wiþ noyse & wiþ bytinge and wakeþ hem of here reste. [John of Trevisa, transl. of Bartholomew de Glanville's "De proprietatibus rerum," 1398]
Any of various small, biting, two-winged flies, such as a biting midge or black fly.