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NATURAL HISTORY. 



Other species are still more particularly limited to certain animals, such as the Squirrel, the 

 Hedgehog, the Mole, Mice and Rats, and Bats. The common Fowl also has its particular Flea 

 (P. gallince) ; another infests Pigeons, whilst others are found in the nests of small birds and 

 Swallows. The largest British species lives on the Badger (P. melis), and measures an eighth of an 

 inch long ; an American species (P. gigas) is two lines in length, and a still larger species is described 

 as infesting the Australian Porcupine Ant-eater (Echidna hystrix). The common Flea varies a good 

 deal in size in different localities. Very large specimens are said to occur about the bathing 

 accommodations of some watering-places, and the Flea of the old reading-room of the British Museum 

 used to be noted for its magnitude and bloodthirstiness. 



The muscular strength of the Fleas is exceedingly great. They perform the most astonishing 

 leaps, covering at a single bound a space many times the length of their own. bodies, a faculty which 

 enables them to vanish in the most wonderful manner at the approach of the finger of an intending 

 captor. This extraordinary muscular energy has been taken advantage of in a very curious manner, 



x 15 



SARCOPSYLLA TEN'ETRANS. 

 A, Free Female; B, Female distended with Egzs; c, Organs of Mouth : me, Maxillie; p, Palpi ; /, Labiura; in, Mandibles; e, Epipliarynx. 



Fleas having been trained to drag small coaches and other objects to which they were harnessed, and 

 to perform other tricks, when they were exhibited to an admiring public under the title of " Indus- 

 trious Fleas." 



Besides the ordinary Fleas which occur in all parts of the world upon man and different animals, 

 and which agree closely in their habits and mode of life, we have to notice an American species known 

 as the Nigua, Chigoe, or Jigger (Sarcopsylla penetrans), the female of which has certain habits that 

 render her a more unwelcome guest than the fiercest examples of Pulex irritans. It is a minute 

 species, less than a twentieth of an inch in length, and lives chiefly in the open country, especially 

 among sand whence it is sometimes called the " Sand Flea " but always in or in the vicinity of 

 human habitations, either occupied or deserted. It ranges in America from Paraguay in the South 

 up to Virginia in the North, that is to say, for nearly 30 degrees on each side of the equator, but is 

 particularly abundant in the warmer parts of South America and the West Indies. 



In its general habits and transformations, the Chigoe agrees with the rest of the Fleas, and the 

 adult insects feed freely upon the blood of such men and animals as come in their way, until the time 

 oomes for the female to produce her eggs, when an entire change takes place in her habits, and she 

 becomes a true parasite. The impregnated female, in fact, makes her way into the skin of the feet of 

 men and animals, generally selecting the toes immediately beneath the nails or claws, but sometimes 

 in the case of small mammals, such as Field Mice, going higher up the limb. In any case, she pene- 

 trates the skin until only the extremity of her abdomen is left in contact with the outer air, and it is 

 through very curious stigmata in this part of the body that she now respii-es. The ovaries produce a 

 great number of eggs, and these gradually swell up the abdomen till it frequently attains the sizn 



