Page:Popular Science Monthly Volume 76.djvu/221

Rh ago from Mediterranean Europe and rapidly spread throughout the United States and Canada.

Buffalo gnats and similar species make certain sections of the Mississippi Valley region almost uninhabitable for cattle at times, and dairying in some places is barred because of the abundance of mosquitoes. These are all external attacks which reduce the condition of the creature attacked because of the irritation, pain or actual loss of blood.

There are others that are more truly parasitic, like the bots. Where ever sheep are raised in numbers the herders have their troubles with the species that gets into the nasal passages, causing blind staggers and often death. Cattle are infested by species that lodge under the skin,

forming suppurating sores along the back. These reduce the condition of the animal and materially lessen the value of the skin. Horsemen know to their sorrow the species that fixes on the walls of the stomach, often in such numbers as to kill the animal. To realize the amount of suffering caused to their hosts by these insects and others with similar habits is almost impossible. To estimate the money loss caused to man has been attempted and the figures run to astounding sums.

But the end is not even yet, for these same animals often suffer from diseases similar to those of man and like them transmissible through or carried by insects. Ticks are not insects, but the economic entomologist is often expected to deal with them, hence we may just mention the cattle tick in connection with Texas fever, which has destroyed and still destroys its thousands and causes enormous money losses.

Many of our birds suffer from maladies similar to malaria, caused by a Proteosoma, and even the common and ever vociferous sparrow is not exempt. These species of Proteosoma find their intermediate hosts in certain species of Culex or whatever the present equivalent