CHIGGER 



419 



Fig. 184. Chigger or burrowing flea, Der- 

 matophilus penetrans, gravid female. X 18. 

 (After Moniez.) 



protruding end of the abdomen. Sometimes the entire female 



is expelled with her eggs l)y the pressure of the inflamed tissue 



which surrounds her. The 



eggs, which fall to the 



ground, soon hatch into 



typical flea larvae (Fig. 185). 



These, if they happen to 



fall on sandy soil under 



conditions suitable for 



their development, grow 



to maturity, pupate in a 



cocoon and emerge as adult 



insects in the course of ten 



days or two weeks. 



The wounds made by the 

 burrowing female in the skin 

 become much inflamed and very painful. Frequently the dis- 

 tended abdomen of a flea is crushed and the eggs released in the 

 wound. In such cases the inflammation is greatly increased un- 

 less the crushed body and eggs are immediately expelled. As 

 soon as the eggs are laid, or even before, the skin surrounding the 

 wound ulcerates and pus is formed. The empty female flea is ex- 

 pelled. The sore which is left 

 is very liable to infection by bac- 

 teria and frequently results in 

 the loss of toes or even whole 

 limbs through blood-poisoning. 

 Quiros has recently pointed out 

 that in Central America, where chigger infection is very common, 

 especially in boys who play barefooted in the streets along which 

 infected hogs are driven to public market, deaths from tetanus 

 and gas gangrene from chigger wounds are very common. 



Although usually only a few chiggers are present at a time, 

 there are cases where hundreds infest a person at once, literally 

 honeycombing the skin and making the feet or other parts of 

 the body so sore that the victim is rendered a complete invalid. 

 This obnoxious flea formerly existed only in the tropical por- 

 tions of America, especially in the West Indies, but it was intro- 

 duced to the West Coast of Africa in 1872, and has since become 

 abundant throughout the tropical parts of that continent and 



Fig. 185. Larva of chigger, Dermatoph 

 ilus penetrans. (After Newstead.) 



