PROC. ENT. SOC. WASH., VOL. 24, XO. 7-8, OCT.-NOV., 1922 199 



"Today I saw the dragon-fly . 

 Come from the wells where he did lie; 

 An inner impulse rent the veil 

 Of his old husk; from head to tail, 

 Came out clear plates of sapphire mail. 

 He dried his wings: like gauze they grew; 

 Thro' crofts and pastures wet with dew 

 A living flash of light he flew. " 



That the mendacious and detestable house-flea, still so com- 

 mon in some European countries, which are supposed to rest 

 on the very crest of advanced civilization, was equally common 

 there from three to five hundred years ago, seems evident from 

 the testimony of Chaucer, Shakespeare, Butler and Swift. As 

 fleas are now known to be vectors of bubonic plague, this is most 

 significant when we consider that the first three of these poets 

 existed before or during the period of the great plague of Lon- 

 don, and Swift was born two years after the most terrible out- 

 break of the disease that ever occurred in Britain. Perhaps the 

 best known poetical passage relative to the flea is that occurring 

 in Jonathan Swift's Rhapsody, but which is often credited to his 

 critic, Dr. Johnson. There are numerous versions of this but 

 the original is: 



"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." 



There can be but little doubt that Swift received the inspira- 

 tion for this idea from the announcement by Anthony Van Leeu- 

 wenhoek, a Dutch contemporary naturalist, that the house flea is 

 parasitized in the pupal stage, and so was able to make use of it 

 in this witty and humorous way. 1 



A less known passage occurs in Butler's Hudibras, where he is 

 telling of the great wisdom of one of his characters and that he 



knew: 

 t 



"How many scores a flea will jump, 



Of his own length, from head to rump. 

 Which Socrates and Chaerephon 

 In vain assayed so long agone; 

 Whether his snout a perfect nose is 

 And not an elephant's proboscis." 



This appertains to Aristophane's comedy of the "Clouds," in 

 which a flea jumps from Socrates's forehead to the head of 



'See Dr. D. F. Harris, Scientific Monthly, Feb. 1921. 



