PARASITOLOGY. 97 



The male is six to seven inches long ; the female 

 eight to ten ; the tail of the female is straight ; she 

 is ovoviviparoiis. Life Cycle. — The mosquito is 

 known to be an intermediate host; in the intestinal 

 tract of this insect the minute embryo finds its way 

 up the Malpighian tubes and there passes through 

 a non-motile stage into the larva. Later the larva 

 becomes motile and migrates through the tissue to the 

 head and enters the proboscis ; thus the dog is inocu- 

 lated with the larval form at the time the mosquito 

 punctures the skin. Animal Infested. — The dog. 

 Parts Infested. — Right side of the heart and the pul- 

 monary artery. 



Injury to Host. — Perhaps the first symptom noticed 

 v^ill be dullness, followed by debility and dropsy ; 

 the dog is seized with convulsions, which become 

 more severe as the worms become more numerous ; 

 vomiting has been noted : the patient usually dies in 

 convulsions. 



Post Mortem Findings. — In some cases hundreds 

 of worms may be found in the right side of the heart 

 and in the pulmonary artery ; in other instances a 

 lesser number. Sometimes the worms are found 

 wound in a mass obstructing the passage of blood 

 and causing an endocarditis and endarteritis. 

 ASCARIDAE. 



The family Ascaridae are commonly called Luin= 

 bricoids because they resemble the earth w^orms in 

 shape and color. They include a group of worms 

 the bodies of which are much larger in calibre than 

 the preceding family. The head parts are provided 

 with three lips, and in most species stand out promi- 

 nently, being marked by a constriction posteriorly. 

 Species of this family infest the intestines of all 



