Fleas 



plague from rats to human beings, and from one person to 

 another. 



A curious and aberrant flea is the so-called "chigoe" or chigger 

 of tropical America (Sarcopsylla penetrans), not to be confused 

 with the so-called chigger of Virginia and southward, which is 

 the larva of a mite. The female of the chigoe, sometimes found 

 in tropical Florida, and frequently brought to our southern sea- 

 ports (New Orleans, Savannah and Charleston), buries the 

 forepart of her body in the flesh of human beings, the abdomen 

 becoming greatly distended and discharging a number of eggs. 

 Another species of the same genus (S. gallinacea), sometimes 

 called the chicken flea, buries itself in the eyelids of domestic 

 fowls in our southern states and in other parts of the world. 



Life- History of the Cat and Dog Flea 



(Pulex serraticeps Gervais.^ 



This insect, commonly known as the cat and dog flea, as 

 stated above, occurs on a number of different animals, and in the 

 northeastern United States at least is the common flea, which 

 proves a pest in houses. The true human flea, so-called 

 (P. irritans), seems to be very rare in the United States, although 

 common enough in Europe, as travelers and those who have 

 read Mark Twain's account of the "chamois" well know. The 

 eggs of the cat and dog flea are deposited between the hairs of 

 the infested animals, but are not fastened to them, so that when 

 the animal moves about or lies down, large numbers of the eggs 

 will be dislodged and drop to the ground or floor, or wherever 

 the animal may be at the time. An easy way t o collect them, 

 therefore, is to lay a strip of cloth for the animal to sleep upon, 

 and afterwards brush the cloth into a receptacle, in which the 

 eggs will be found in numbers. The eggs hatch under favorable 

 circumstances in from two to four days, and the young larvae, 

 very slender and elongate, white in color, and of the structure 

 shown in the accompanying figure, crawl into the floor cracks 

 and feed upon the accumulated dust. They may be reared under 

 observation, in saucers, between layers of blotting paper, with 

 dust and bread crumbs. Specimens studied by Mr. Pergande, at 



193 



