24 BULLETIN 260, IT. S. DEPARTMENT OF AGRICULTURE. 
country, and is the usual host of Dioctophyme renale, the giant kid- 
ney worm, which is a huge red worm a yard long and as thick as a 
little finger, occurring in the kidney or abdominal cavity of man, the 
cow, the horse, and the hog. This last-named worm has been found 
in this country on a number of occasions. Strongyloides stercorals, 
the parasite of Cochin China diarrhea, can be readily transmitted to 
dogs, and a Strongyloides, apparently this species, is found in dogs 
in China and Japan. 
Mites, fleas, etc. — The dog is affected by a form of mange or scab 
due to a mite known as Sarcoptes scabiei canis. This disease occurs 
in this country and may be transmitted to man, causing more or less 
discomfort. The dog is also known to be attacked by and transmit 
the sarcoptic scab of sheep, a rather rare form of scab due to the mite 
Sarcoptes scabiei ovis. 
In addition to being the adult host of the aberrant spiderlike form, 
Linguatula rhinaria, the larva of which may occur in man, the dog is 
a host for the larval form of two closely related species, Porocephalus 
armillatus and P. moniliformis, which may also pass their larval 
stage in man. 
The dog is not only a host for the cosmopolitan fleas Pulex irritans 
and C tenocephalus canis, but is also a host for the widely distributed 
chigger flea, or chigoe, Dermatophilus penetrans (Sarcopsylla pene- 
trans), of tropical countries and native in the southern portion of 
North America. This flea attacks men, cattle, horses, mules, sheep, 
goats, and hogs, the female becoming embedded in the skin and grow- 
ing to the size of a pea. 
Finally, the dog is an important host of the parasitic larvae of 
certain flies which also habitually attack human beings and live 
stock. One species, Derm.atobia cyaniventris, occurs in South and 
Central America, and another, C ordylobia anthropophaga, occurs in 
Africa. These larvae undergo their development beneath the skin, 
causing boil-like tumors and abscesses. Another species, Paralucilia 
macellaria (Chrysomyia macellaria), is a serious pest in the southern 
United States. Its larvae, commonly called screw worms, attack 
cattle, horses, and other animals, including dogs and human beings. 
These screw worms may undergo their development in the carcasses 
of dead animals as well as in the tissues of live animals. 
CONCLUSION. 
The parasites discussed in this paper do not nearly exhaust the list 
of those present in the dog, but only those known also to affect man 
or live stock. 
In conclusion it may be said that the dog is at present the subject 
of numerous criticisms from three quarters. For over half a century 
