92 PARASITOLOGY. 



the female is straight; she is ovoviviparous. The 

 caudal extremity of the male is provided with two 

 spiculae of unequal length and two anal papillae. 

 The head is provided with two lateral lips. 



Life History. — Ransom has shown that the larva 

 of horse flies breeding in manure, devour the ova 

 in which parasite it develops to fully mature larva by 

 the time the flies are mature. Horses taking these 

 flies into the stomach become infested. 



Animals Infested. — The horse, the ass and the mule. 



Part hiksted. — The stomach, 



Injury to Host. — The worms maybe found in myr- 

 iads, free in the stomach contents. Occasionally one 

 will be found with its head lodged in the mouth of 

 a duct of a gastric gland. They may produce ulcers 

 and gastritis and interfere with the health of the 

 animal. 



Treatment .—^^x\z\xiQ and gasoline, in doses of two 

 to four drams, followed by physic. 



Spiroptera Strongylina (Strongylos — round) . 



Synonym. — Ardiienna strongylina. 



Distribution. — Found in Europe; very common in the 

 United States. 



Description. — A small white worm, thread-like in cali- 

 bre. The male is about one-half inch in length; the female 

 three-fourths to four-fifths of an inch. The mouth is round, 

 and is not provided with lips or papillae. The worm may 

 be straight or curved in a half-moon shape; it has narrow 

 lateral wings on each side, just posterior to the head. 



Tail of male is tightly coiled, one and one-half times 

 and is provided wi'th two broad unequal mernbraneous 

 alae, six papillae and two spicule. 



Animal Infested, — The hog. 



Part Infested. — The stomach. 



Injury to Host. — The worms are usually found free 



although they have been reported to have formed 



