Spiders and Their Near Relatives 



or Texas-fever as it was formerly called, from one animal to 

 another. This disease has caused the death of thousands of cattle 

 in this country; and makes it extremely difficult to introduce 

 cattle from the North into the South. This tick is found only 

 in the South and the Federal Government has established a 

 quarantine line across which cattle are not allowed to be shipped 

 or driven without being freed from the ticks. 



The Department of Agriculture at Washington and several 

 of the Southern Experiment Stations have issued publications 

 giving the life history of this tick in great detail and suggestions 

 as to methods of preventing the spread of the disease; these can 

 be obtained on request by any one interested in the subject. In 

 some of these publications this tick is designated as Margaro- 

 pus annulatus (Mar-gar'o-pus an-nu-la'tus). 



The cause of the disease is a protozoan parasite Babesia 

 bovis (Ba-be'si-a bo'vis), which lives in the blood of cattle, destroy- 

 ing the red blood corpuscles and which is transferred from one 

 animal to another by the tick. Even the young of ticks that 

 have infested diseased cattle may transmit the disease. 



Superfamily GAMASOIDEA (Gam-a-soi'de-a) 



The Gamasid Mites 



The Gamasid mites are often observed attached to beetles 

 and other terrestrial insects upon which they spend a part of 

 their life. It was formerly believed that these mites were para- 

 sites of the insects, but it has been found that they are nymphs 

 which secure transportation in this way, a method of distribution 

 of the species. 



A few species are parasitic on birds, bats, and small mammals; 

 some are found in ant-nests; a great many occur among fallen 

 leaves, and some live in decaying substances, either animal or 

 vegetable. Most species prey on small insects or on other mites. 

 Among those found on insects, some are attached by an anal 

 pedicel formed of excretions. 



Among the species that are parasitic on birds there is one 

 Dermanyssus gallince (Der-ma-nys'sus gal-li'nae), which is a 

 serious pest of poultry. The mites of this species hide in cracks 

 and crevices by day, but at night crowd upon the fowls and suck 



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