14 
BULLETIN 3 8, PUERTO RICO EXPERIMENT STATION 
duces considerable irritation and inflammation. The infested tis- 
sues become swollen and pits or ulcers are produced. In a badly 
infested foot the skin appears honeycombed. Providing a concrete 
wallow containing 3 to 5 inches of water with a thin layer of 
crude oil will control lice and would probably be effective in con- 
trolling sand fleas. A hog wallow should be provided with a 
roof for shade. The construction and medication of hog wallows 
are fully described in a Farmers' Bulletin of the United States 
Department of Agriculture. 5 
Other external parasites that have been found on the pig are : 
Mosquitoes ; gnats or mimes, Hippelates spp. ; fleas other than sand 
fleas; horse ticks, Demiacentor nitens, in the ear; and leeches or 
sanguijuelas. ' 
5 See footnote 4. 
U. S GOVERNMENT PRINTING OFFICE : 1936 
