SIPHONAPTERA 883 



line; the genal margin of the head is produced into a triangular 

 process at the ventral oral angle; and ctenidia are lacking. The 

 two following species are the best-known members of this family. 



The sticktight flea, Echidnophaga gallindcea. — This is a very- 

 serious pest of poultry especially in the southern and southwestern 

 portions of the United States. It is a small, dark brown species, which 

 is often found in dense masses attached to its host ; heads of chickens 

 are often covered with dark patches of these fleas. This species is 

 known as the sticktight flea because it seldom hops about, biting here 

 and there, as do most fleas, but settles down on its host, deeply insert- 

 ing its mouth-parts, and remains for days or weeks. While this 

 species is chiefly a pest of poultry, it is often found in dense masses 

 on the ears of dogs and cats. 



The chigoe (chig'o) or jigger, Tunga penetrans. — This is a small 

 flea found in the West Indies, Mexico, Central and South America, 

 and in tropical Africa. It has been reported from Florida but it is 

 not known to be established in the United States. The males and the 

 unimpregnated females live in dry, sandy soil ; they are only about one 

 millimeter in length, and behave in the ordinary manner of fleas, 

 feeding on the blood of man and many other animals, domestic and 

 wild, and even birds. When impregnated, the female burrows into 

 the skin of her host. Soon after this the abdomen becomes distended 

 with eggs and acquires the size of a small pea. This species often 

 causes serious injury to man by burrowing beneath the skin of the 

 foot, causing the formation of a sore, which may become infected 

 with bacteria, and cause the loss of a toe or a leg. 



In the southern United States the names chigoe and jigger are 

 improperly applied to the harvest-mites, which are the immature 

 six-legged forms of various mites that attach themselves like ticks to 

 the skin and become gorged with blood. 



