FLEA (פַּרְעֹ֣שׁ), flea all Eng. VSS. The flea is mentioned twice (1 Sam 24:14 [all Eng. VSS]; 26:20 [not RSV]). These are metaphorical passages which confirm the tr., for killing fleas as they hopped actively around was a familiar occupation. Fleas (Pulex and Ctenocephalides species) belong to a small and highly specialized insect family. The adults are bloodsuckers and each species normally concentrates on one host. The larvae are not parasitic but live on rubbish, so that human species thrive where there is dirt. In the dry conditions of Pal. fleas often swarm and may be regarded with indifference by the local folk. Besides causing much discomfort, fleas can transmit several diseases, in particular bubonic plague (see Mouse).
International Standard Bible Encyclopedia (1915)
(par`osh; compare Arabic barghut, "flea," and barghash, "mosquito" (1Sa 24:14; 26:20); kinnim (Ex 8:16), "lice," the , margin "sandflies" or "fleas"; Septuagint skniphes, probably best rendered "gnat"; see Gnat; Lice):
In 1Sa 24 Saul seeks David in the wilderness of En-gedi, and David, after cutting off the skirt of Saul’s robe in the cave, calls out to him, "After whom is the king of Israel come out? after whom dost thou pursue? after a dead dog, after a flea" (24:14). Again in 1Sa 26:20 Saul seeks David in the wilderness of Ziph, and David after taking the spear and cruse from beside Saul while he slept, cries out to him, ".... the king of Israel is come out to seek a flea, as when one doth hunt a partridge in the mountains." The flea is here used as a symbol of David’s insignificance, coupled perhaps, in the second passage, with a thought of the difficulty that Saul had in laying hands on him. In Encyclopedia Biblica Cheyne finds fault with a similar interpretation given in DB on the ground that it is absurd that David should refer to hunting "a single flea," and proposes to change par`osh ’echadh "a flea," to pere’ midhbar, "wild ass of the desert." The writer will only say that no observant resident of Palestine would consider the textual alteration to be called for.
Linnaeus recognized two species of flea, Pulex irritans, the common parasite of man, and Pulex (Sarcopsylla) penetrans, the tropical and sub-tropical jigger flea. More than a hundred species are now listed, and the recent discovery that certain fleas are instrumental in the transmission of the plague has given a new impetus to the study of these tiny pests. A flea that is often commoner in houses than Pulex irritans is the "dog and cat flea," variously known as Pulex serraticeps, Pulex canis, Pulex felis or Ctenocephalus canis.