40 



Methods of control — Establishment of a quarantine line limiting 

 area infested by the tick and prohibiting removal of cattle, except 

 for immediate slaughter, during the period when the tick could live 

 and develop in the North. Cattle going to market during the 

 closed season must be shipped in special cars or boats and, when 

 unloaded for feeding, watering, or sale, are placed in special pens. 

 Cars and boats must be disinfected before other stock can be carried. 

 Cattle may be freed of ticks by hand-picking, greasing, dipping, or 

 spraying. The most important measures are those which, by taking 

 advantage of a minute study of the biology of the tick, render it 

 possible to free infested pastures. Essentially, exclude from the 

 pasture from June until late fall all cattle or horses and mules which 

 might carry ticks. In the meantime, cattle from the infested field 

 are freed from ticks by placing in a tick-free feed lot for three weeks 

 by which time many ticks would drop off, but seed ticks would not 

 have hatched. Then place in a second tick-free lot for twenty days, 

 and finally, for certainty that ticks had all dropped off, place in a 

 third lot. By this time the tick-free cattle should be placed in a 

 forage field until mid-November, by which time all the ticks in the 

 original pasture will have died. By essentially this method large 

 areas of the quarantined region are being freed from ticks and hopes 

 are entertained that the tick may be exterminated. For details see 

 Farmers' Bulletin 378, "Methods of Exterminating the Texas Fever 

 Tick" and various publications of the Bureau of Animal Industry 

 and of the Bureau of Entomology. 



Superfamily GAMASOIDEA 



Abdomen not annulate; "tongue" small, without teeth, venter 

 without furrows, body often with coriaceous shields, posterior margin 

 never crenulate; no eyes. This family includes many species free- 

 living or attached to insects, but one group is parasitic on birds, bats, 

 rodents, etc. One species of very great economic importance is : 



Dermanyssus gallinae, the red chicken mite. Incorrectly called 

 "chicken tick". Most destructive external parasite of fowls. 



Description — "Body ovopyriform, posterior end largest, slightly 

 flattened from above to below; abdomen margined by short, well- 

 separated bristles; color varying from yellowish- white to dark red, 

 according as the insect is fasting or more or less replete; the intestinal 



