Fleas are the insects forming the order Siphonaptera. They are wingless, with mouthparts adapted for piercing skin and sucking blood. Fleas are external parasites, living by hematophagy off the blood of mammals (including bats and humans) and birds.

Some flea species include:

• Cat flea (Ctenocephalides felis)
• Dog flea (Ctenocephalides canis)
• Human flea (Pulex irritans)
• Moorhen flea (Dasypsyllus gallinulae)
• Northern rat flea (Nosopsyllus fasciatus)
• Oriental rat flea (Xenopsylla cheopis)

Over 2,000 species have been described worldwide.

Noun

flea (plural fleas)

1. A small, wingless, parasitic insect of the order Siphonaptera, renowned for its bloodsucking habits and jumping abilities.
2. A thing of no significance.

• flea market
• sand flea
• sand fly
• sandfly

Fleas are wingless insects of the order Siphonaptera with mouthparts adapted for piercing skin and sucking blood. Fleas are external parasites, living by hematophagy off the blood of mammals (including bats and humans) and birds.

Sourced

Hoyt's New Cyclopedia Of Practical Quotations (1922)

Quotes reported in Hoyt's New Cyclopedia Of Practical Quotations (1922), p. 277.

• Great fleas have little fleas upon their backs to bite 'em, And little fleas have lesser fleas, and so ad infinitum. And the great fleas themselves, in turn, have greater fleas to go on; While these again have greater still, and greater still, and so on.
  • Augustus De Morgan — A Budget of Paradoxes. P. 377. Compare Swift, below.

• "I cannot raise my worth too high; Of what vast consequence am I!" "Not of the importance you suppose," Replies a Flea upon his nose; "Be humble, learn thyself to scan; Know, pride was never made for man."
  • Gay — The Man and the Flea.

• A blockhead, bit by fleas, put out the light, And chuckling cried, "Now you can't see to bite."
  • In Greek Anthology.

• It was many and many a year ago, In a District styled E. C., That a monster dwelt whom I came to know By the name of Cannibal Flea, And the brute was possessed with no other thought Than to live — and to live on me.
  • Thos. Hood, Jr. — The Cannibal Flea. Parody on Poe's Annabel Lee.

• I do honour the very flea of his dog.
  • Ben Jonson — Every Man in his Humour. Act IV. Sc.4.

• Then mimick'd my voice with satyrical sneer, And sent me away with a Flea in my ear.
  • Mochus — Idyll LX. Eunica. Beaumont and Fletcher — Love's Cure. Act III. Sc. 3.

• Panurge auoyt la pulee en l'oreille.
• Panurge had a flea in his ear.
  • Rabelais — Pantagruel. Ch. XXXI. Simon Forman — Notes to Marriage of Wit and Wisdom.

• So, naturalists observe, a flea Has smaller fleas that on him prey; And these have smaller still to bite 'em, And so proceed ad infinitum. Thus every poet in his kind Is bit by him that comes behind.
  • Swift — Poetry. A Rhapsody. Compare De Morgan, above.